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Institute for Materials Science and Engineering

METALLURGY

NAS-NRC

Assessment Panel

February 2-3, 1 989

NISTIR 88-3843

U.S. Department of Commerce

National Institute of Standards

and Technology

Q C

100

. U56

88-3843

1989

r . 9

Technical Activities

1988
NATIONAL INSTITUTE OF STANDARDS &

TECHNOLOGY

Research Information Center

Gaithersburg, MD 20899

Eddy Current Sensor used for

measuring the density of metal

samples in real-time during

hot-isostatic-pressing (HIP).
.UZb

Institute for Materials Science and Engineering

ME1ALUURGY

E.N. Pugh, Chief

J.H. Smith, Deputy

NAS-NRC

Assessment Panel

February 2-3, 1 989

NISTIR 88-3843

U.S. Department of Commerce

National Institute of Standards

and Technology

Technical Activities
9>
METALLURGY DIVISION

CHIEF

E. Neville Pugh

Phone: (301) 975-5960

DEPUTY CHIEF

John H. Smith

Phone: (301) 975-5961

SPECIAL ASSISTANT

Steve C. HardyPhone: (301) 975-6159

GROUP LEADERS

Advanced Sensing

Haydn N. G. Wadley

Phone: (301) 975-6140

Corrosion

Dale E. Hall

Phone: (301) 975-6022

Electrodeposition

David S . Lashmore

Phone: (301) 975-6405

High Temperature Materials Chemistry

John W. Hastie

Phone: (301) 975-5754

Magnetic Materials

Lawrence H„ Bennett

Phone: (301) 975-5966

Mechanical Properties of Metals

John H. Smith

Phone: (301) 975-5961

Metallurgical Processing

J ohn R . Manning

Phone: (301) 975-6157

ii

ABSTRACT

This report summarizes the FY 1988 activities of the Metallurgy

Division of the National Institute of Standards and Technology

(NIST) . These activities center upon the structure-processingproperties relations of metals and alloys and on methods of

measurement; and also include the generation and evaluation of

critical materials data. Efforts comprise studies of metals

processing and process sensors; advanced materials, including metal

matrix composites, intermetallic alloys and superconductors;

corrosion and electrodeposition; mechanical properties; magnetic

materials; and high temperature reactions.

The work described also includes four cooperative programs with

professional societies and industry: the Alloy Phase Diagram

Program (with ASM INTERNATIONAL); the Corrosion Data Program (the

National Association of Corrosion Engineers) ; the Steel Sensor

Program (the American Iron and Steel Institute); and the Temperature

Sensor Program (the Aluminum Association).

The scientific publications, committee participation, and other

professional interactions of the 79 full-time and part-time

permanent members of the Metallurgy Division and its 48 guest

researchers are identified.

iii
» . * . - ,
TABLE OF CONTENTS

PAGE

OVERVIEW 1

METALLURGY DIVISION

ORGANIZATION CHART . ........ 7

RESEARCH STAFF .... 8

TECHNICAL ACTIVITIES

Metallurgical Processing ................. 15

Advanced Sensing ..................... 29

Corrosion . 45

Electrodeposition ..................... 57

Magnetic Materials .................... 67

High Temperature Materials Chemistry ........... 73

Mechanical Properties of Metals .............. 81

OUTPUTS/INTERACTIONS

Recent Publications .................... 89

Industrial and Academic Interactions .... . . 103

Technical/Professional Committee

Leadership Activities ................... 115

APPENDIX

Organizational Chart

National Bureau of Standards ............... Al

Organizational Chart

Institute for Materials Science and Engineering ...... A2

v

OVERVIEW

METALLURGY DIVISION (450)

E. Neville Pugh, Chief

John H. Smith, Deputy Chief

June Toms, Secretary

The basic programs in the Metallurgy Division fall into the traditional NIST

areas of measurement science, materials characterization, and data and SRMs

,

but many have undergone radical changes over the past few years. In response

to a clear mandate to assist in increasing the nation's industrial

competitiveness, emphasis in measurement science continues to move towards

processing, specifically to process sensors and, in some instances, to

process modeling and automated process control. The focus on processing has

also led to a more direct interaction with industry, as evidenced by the

consortium for powder atomization and other joint programs. In materials

characterization, the thrust is towards new, advanced materials, including

metal matrix composites, intermetallic alloys, and nanocrystalline magnetic

materials, as well as high Tc superconductors. The Corrosion Data Program

(with NACE) has replaced the successful Alloy Phase Diagram Program (with ASM

International) as our largest data activity. It will be seen in the

following summary that there is considerable cross cutting between the main

program areas, and that many programs involve strong interactions between the

seven groups which constitute the Division.

The major programs are conveniently grouped into three categories:

Metals Processing and Sensors

Powder processing represents a major current thrust, with programs involving

both powder atomization and consolidation. The former centers on the

Metallurgical Processing Group's high pressure inert gas atomizer, and

involves a cooperative effort with industry in the form of a consortium and

with other centers in NIST. This program is directed towards the measurement

and real-time control of particle size, such control being important for

efficient consolidation and to obtain desired properties, particularly in RSP

applications. In the first year of the consortium, approximately twenty lOKg

batches of Type 304 steel were atomized, both to determine the effects of

parameters such as die pressure, the ratio of the gas and metal flow rates,

and metal superheat, and to study in- situ particle size measurement

techniques. Particle size and distribution was also measured off-line by

sieving. At present, a laser diffraction technique shows promise as an insitu sensor. Modeling of the atomization process requires detailed

information on the way in which the molten stream breaks into fine droplets,

and direct studies of the plume have been initiated using high speed

photograhy and laser holography. These studies are being carried out

cooperatively with fluid mechanics experts from the Center for Chemical

Engineering.

Powder consolidation studies focus on hot isostatic pressing (HIP) . In a program jointly sponsored by DARPA and carried out in the Advanced Sensing

1
and Metallurgical Processing Groups, sensors are being developed to monitor

the consolidation process in real time. These studies are aimed at Ti-Al

intermetallics but preliminary studies have also been carried out on copper.

Considerable progress has been made with an eddy current sensor to measure

shrinkage as densification proceeds; this technique permits dimensional

changes of a few microns to be measured. An ultrasonic sensor to monitor

microstructural changes is in an earlier stage of development. A theoretical

model of the HIP process has been developed by Ashby, University of

Cambridge, who serves as a consultant to the project. The experimental data

have revealed several ways in which the model should be modified to give a

more complete description of the HIP process. In the final stage of the

program, an intelligent control system, currently being developed by the BDM

Corporation, will compare the sensor data to the predictions of the upgraded

theoretical model, and recommend changes in the process schedule. By this

means it should be possible to obtain an end product with the desired

characteristics even in the presence of variations in the starting material.

Other sensors are being studied in the Advanced Sensing Group. The eddy

current technique mentioned in the HIP project is also being used in a

collaborative program with the Aluminum Association to measure the internal

temperature of aluminum during extrusion. A plant demonstration in 1987

demonstrated the practicality of this non-contact method for cylindrical and

square-section products, and it is now being extended to more complex shapes

where through- transmission must be used. Further demonstrations are planned

for later in 1988, one at a plant and one at NIST. Work has also continued

on the ultrasonic time of flight system being developed with the American

Iron and Steel, Institute. Earlier laboratory tests demonstrated the

feasibility of the method for measuring the internal temperature of solid

steel, and it is now being evaluated in field tests. In the laboratory, the

approach is now being extended' to determine the position of the liquid- solid

interface in partially solidified material, knowledge necessary for processes

such as continuous casting and skull melting. To date this work has been

carried out largely on aluminum because of its relatively low melting point,

and the results have been encouraging. Studies on Rene 95 are now in

progress

The High Temperature Materials Chemistry Group is continuing its development

of thermochemical computer models for liquid iron and steel processing. Such

models are particularly timely in view of recent renewed interest by industry

in developing radically new direct reduction steel making processes. The

modeling research is supported by solution thermochemical data obtained using

an unique high pressure, high temperature mass spectrometer facility which

allows measurements to be made at temperatures, pressures and compositions

representative of steel processing conditions.

Characterization of Advanced Materials

Metal matrix composites (MMC) , represent an important emerging technology in

which we have mounted a significant effort, cutting across several groups.

The bulk of the work so far has been carried out on SiC fibers in matrices of

aluminum or its alloys, and has focussed on the fiber-matrix interface, which

controls the performance of the composites. In the Metallurgical Processing

Group, TEM studies are being conducted to determine the interface structures

2
corresponding to conditions simulating molten metal infiltration, and these

are correlated with phase diagram calculations of equilibrium and nonequilibrium phase formation; the results have shown, for example, that the

brittle intermetallics Al 4 C3 and Al 4 SiC4 can form under some conditions, and

that the morphologies of the Al-SiC and Al 4 C3 -SiC interfaces are strongly

influenced by the SiC grain structure. As part of the studies, a technique

has been perfected to grow, from the melt, Al monocrystals containing a

single SiC fiber. These samples have been used by the Advanced Sensing Group

to study the mechanical behavior of the interface for different thermal

histories, using the acoustic emission technique to monitor deformation, and

to examine the perfection of the interface with an ultrasonic "leaky wave"

me thod.

The Electrodeposition Group is continuing its novel approach to composites,

using electrodeposition to coat the fibers with an Al alloy, possibly with an

intermediate layer to optimize the interfacial structure or as a. barrier for

improved performance at elevated temperatures. The coated fibers may then be

consolidated by conventional infiltration techniques, or the matrix may be

built up by electroforming followed by a hot pressing operation. A cell for

alloy deposition on moving fibers has been completed, and the process has

been successfully modeled. Over the past year, effort has focussed on

depositing and characterizing Al-Mn matrixes, the manganese enhancing the

nucleation process, and Al-Ti matrices for intermetallic composites. Results

to date are promising for both systems. In related cooperative work with the

American Cyanamid Company, Co-W layers have been successfully plated onto

graphite fibers to produce effective barrier layers.

Intermetallic alloys represent another major activity in this program area.

It was seen that HIP studies and alloy electrodeposition are being carried

out on Ti-Al alloys, which are potentially important for high temperature

structural applications. A major DARPA supported program on ternary alloys

based on this system is in progress in the Metallurgical Processing Group.

This research is directed towards the examination of processing paths using

precursor metastable phases produced by rapid liquid and solid state

quenching, an approach which offers possibilities of micros tructural

manipulation beyond those available by conventional processing. For example,

rapid solidification of Ni2 TiAl (normally the L2 : structure) has caused the

formation of an ordered BCC (B2) phase, and subsequent heat treatment causes

the formation of L2 1 cuboids in a B2 matrix. A general theory has been

constructed to predict the formation of such unusual microstructures. Solid

state quenching experiments are being conducted in the Ti-Al -Nb system.

Examination of phase equilibria and transformations has led to the

delineation of a large ternary field of ordered BCC which is thought to be

important in establishing the properties of the alloy • system. Decomposition

of the quenched B2 phase is currently being investigated.

Nickel aluminides are being studied in the Corrosion Group. In this program,

materials supplied by Oak Ridge National Laboratories are being characterized

for resistance to aqueous corrosion and environment induced embrittlement.

Work to date has established that the alloys display good resistance to

general and pitting corrosion in neutral and alkaline solutions, but undergo

severe hydrogen embrittlement in acid conditions. Further work is in

3
progress to determine if localized attack can produce acidification in

neutral solutions which might lead to hydrogen absorption.

A new activity has been undertaken by the High Temperature Materials

Chemistry Group on the oxidation mechanisms for refractory intermetallics and

composites. The program is supported by DARPA, and an industrial advisory

panel provides guidance on the research directions. Initial studies involve

determination of the basic thermochemistry of Nb-Al-O, a system of central

importance to the development of refractory structures for hypersonic

vehicles

Advanced magnetic and superconducting materials have been characterized in

the Magnetic Materials Group's newly modernized magnetic materials

laboratory. High Tc superconductors based on either rare earths, bismuth or

thallium, have been measured as bulk materials and as laser-ablated thin

films. Magnetic hysteresis, magnetic viscosity, flux creep, superconducting

onset temperatures, magnetic critical currents, and in iron- substituted

samples, magnetic hyperfine fields have all been investigated. The thin

films were measured using a novel magnetically-modulated-microwave- absorption

(MAMMA) technique. The High Temperature Materials Chemistry Group has

started investigations on the detailed character of the "plume" in the laserablation process. Magnetic measurements on Ni/Cu compositionally-modulated

thin films produced by the Electrodeposition Group with their improved

electroplating procedure exhibited (1) high magnetizations and (2) smaller

temperature dependencies of the magnetization than any reported previously by

any technique. These results demonstrate that electrodepositing nanometer

thick layers of the highest quality is feasible. Thin films of a magnetic

and a nonmagnetic constituent with a nanometer- sized granular morphology have

been produced both by sputtering and by a sol -gel method. These

nanocomposites were characterized by Mossbauer spectroscopy, x-ray

diffraction and, of special importance, field-emission scanning-electron

microscopy (FESEM)

Data and SRM Programs

The Alloy Phase Diagram Program on binary alloys, conducted cooperatively

with ASM International, is drawing to a successful conclusion. Development

and loading of the interactive database containing numerical and graphical

data for nearly 1,600 binary systems was completed in 1988 and the database

transferred to ASM for dissemination. In addition to providing the Editor of

the Bulletin of Alloy Phase Diagrams, the Division's remaining activity in

the binary program is the evaluation of the iron binaries. The main thrust

of our program is now in ternary diagrams, both in evaluation of certain

critical systems and in developing a ternary graphics package, and in

providing support for other in-house programs such as those described above

on MMC and intermetallic alloys.

The Corrosion Data Center, formed in cooperation with NACE in response to a

critical need for a centralized, computerized database, continued to expand

in 1988. CORSUR, a program containing a NACE survey of data for metals and

non-metals, was completed and is being distributed by NACE. A comprehensive

database designed to accommodate data from a variety of sources has been

developed, and data from two key industrial sources are currently being

4
entered for subsequent evaluation. In addition, expert systems are under

development in two areas of materials selection, one for the handling and

storage of concentrated sulfuric acid (with MTI) and the other for subsurface pumps for oil and gas production (with a Guest Scientist from the New

Zealand DSIR)

.

Another major data program is being conducted for the Nuclear Regulatory

Commission in their high level waste management program. Specifically, the

Corrosion Group assists NRC in evaluating DOE's activities in waste disposal,

particularly in areas relating to the localized corrosion of the waste

package container. Technical reviews of DOE's technical reports and other

papers are being entered into a computerized database. An experimental

program is also being conducted, primarily to resolve issues arising from the

reviewing process.

The Division continues to maintain a strong program in Standard Reference

Materials. In the Electrodeposition Group, production of coating thickness

standards increased 10% in the past year, and research continued on the

development of a lead- tin standard for the electronics industry. The

Mechanical Properties of Metals Group continued a project with ASTM to

develop test blocks for use in the calibration of Rockwell hardness machines.

An important finding in 1988 was that variations in indenter geometry

contribute significantly to the variability of certain hardness measurements

previously attributed to the test blocks.

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7
RESEARCH STAFF

Metallurgical Processing

Bendersky, Leonid A.

Biancaniello , Francis

Boettinger, William J

Burton, Benjamin P,

Goriell, Sam R.

deWit, Roland

Fields, Richard J.

Gayle, Frank W.

Handwerker, Carol A.

Group

S .

o Analytical transmission electron

microscopy

o Aluminum alloys; quasicrystals

o Intermetallics for high temperature

application

o Inert gas atomization; metal powder

processing and consolidation

o Special alloy, composites, and

quasicrystal preparation

o Melt- spinning ; rapid solidification

o Relation of alloy microstructures to

processing conditions

o High temperature alloys/intermetallics

o Rapid solidification

o Thermodynamic modeling of alloy phase

diagrams

o Experiments on metal -oxide phase

equilibria

o Order-disorder and phase separation in

alloy systems

o Modeling of solidification processes

o Interface stability

o Convection and alloy segregation

during solidification

o Fracture mechanics

o Dislocation theory

o Stereology

o Mechanical properties

o High temperature materials

o Quantitative metallography

o Aluminum metallurgy; intermetallics

o Transmission electron microscopy

o Structure/property relationships

o Interface studies

o Metal matrix composites

o Diffusion- induced grain boundary

migration
Low, III, Samuel R. o Mechanical properties and testing

o Laboratory computer systems

programming

o Automated test design

Hardy, Stephen C. o Alloy coarsening

o Surface tension measurements

o Interface segregation

Manning , J ohn R

.

o Metals processing

o Diffusion kinetics

o Interface reactions

Ridder, Stephen D. o Inert gas atomization; powder

processing

o Microparticle rapid solidification

o Solidification dynamics

Schaefer, Robert J. 0 Hot isostatic pressing of

intermetal lies

o Solidification processes

0 Electron beam rapid solidification

Advanced Sensing Group

Clough, Roger B. o Acoustic emission

o Mechanical properties

0 Surface modification

Kahn, Arnold H. o Eddy current modeling

0 Electromagnetic theory

o Solid state physics

Johnson, Ward L. o Ultrasonics

o Solid state physics

o Point defects in metals &

semiconductors

Norton, Stephen Jo o Ultrasonic, Mossbauer and NMR imaging

o Inverse modeling

Pitchure , David J

.

o Digital electronics

o Ultrasonic instruments

o High temperature measurements

Simmons, John A. o Dislocation theory

o Acoustic emission

o Inverse modeling

Wadley, Haydn N. G. 0 Dislocations and fracture

o Acoustic emission

o Ultrasonics

9
Corrosion Group

Anderson, David B. o

o

o

o

Bertocci, Ugo o

o

o

Escalante, Edward o

oo

Fraker, Anna C. o

o

oo

Hall, Dale E, oo

Harris, Jonice S. o

o

o

Harrison, Steven A. o

o

o

Interrante, Charles G. o

o

o

o

Ricker, Richard E. o

o

oo

Stoudt, Mark R„ o

o

o

Industrial corrosion testing

Corrosion data evaluation

Corrosion database development

Expert systems for corrosion control

Electrochemical measurements

Computer modeling

Passivity and pitting

Underground corrosion

Corrosion in concrete

Corrosion rate measurements

Titanium alloys

Corrosion processes

Transmission electron microscopy

Surgical implant metals

Electrochemistry

Corrosion of advanced materials

Scanning electron microscopy

Corrosion measurements

Mechanical properties

Computer systems programming

Software engineering

Laboratory automation

Hydrogen embrittlement

Nuclear waste disposal

Environmental testing

Welding metallurgy

Environmental induced fracture (stress

corrosion cracking and corrosion

fatigue)

Hydrogen embrittlement

Aluminum alloys

Advanced materials (composites and

intermetal lies)

Physical metallurgy

Corrosion engineering

Environmentally induced fracture

10
Electrodeposition Group

Beauchamp, Carlos R.

Brown, Henrietta J.

Claggett, Sandra W.

Johnson, Christian E.

Kelley, David R.

Lashmore , David S

.

Mullen, Jasper L„

Stafford, Gery R„

o Computer simulation of

electrodeposition processes on moving

fibers

o Electrochemical measurements of

kinetic parameters

o Coating thickness SRM development

o Simultaneous thickness

electropotential (STEP) SRM

development

o Scanning electron microscopy

o Metallographic specimen preparation

o General electroplating

o Ultra-black coatings

o Electroless deposition process

o Metallic glass alloy deposition

o Microhardness SRM research

o Chromium deposition

o Pulsed alloy deposition

o Microhardness SRM development

o Dye penetrant SRM development

o Precious metal electrodeposition

o Plating on aluminum

o Electrochemical mechanisms of coating

processes

o Pulsed alloy deposition

o Composition modulated alloy deposition

o Properties and structure of

electrodeposited coatings

o Amorphous alloys

o Transmission electron microscopy

o Metal matrix composites

o Development of automated hardness

testing

o Electrochemical measurements for

determining metal corrosion

o Analytical spectroscopy

o Electrochemical transients

o Electrodeposition

o Molten salt electrochemistry

11
Magnetic Materials Group

Bennett, Lawrence, H. o

oo

o

o

Shull, Robert D. o

o

o

oo

Swartzendruber , Lydon J. oo

o

o

High Temperature Materials Chemistry

Bonne 11, David W„ o

oo

o

Hastie, John W. o

o

o

o

Mechanical Properties of Metals

Hicho, George E„ o

o

o

o

Shapiro, Alexander o

o

oo

Magnetic measurements

Magnetic thin films

High Tc superconductors

Topology of local environments

Alloy phase stability

Nanocomposites

Magnetic susceptibility

Mossbauer effect

X-ray and neutron diffraction

Scanning electron microscopy

Magnetic susceptibility

Magnetic methods, NDE

Gamma-ray resonance spectroscopy

Barkhausen effect

High temperature -pressure mass

spectrometry

Computer modeling

Levitation calorimetry

Laser- induced vaporization mass

spectrometry

High temperature chemistry of

inorganic materials

Phase equilibria thermochemistry and

solution models

High temperature-pressure mass

spectrometry

Chemistry of combustion

Mechanical metallurgy

Ferrous metallurgy

Failure analysis

Preparation and certification of

standard reference materials

Analytical electron microscopy

X-ray microanalysis

Image analysis

Transmission electron microscopy

12
Shives , T. Robert

Smith, John H.

o Hardness test methods

o Mechanical properties

o Failure analysis

o Mechanical properties of materials

o Fracture of materials

o Structural integrity analysis

13
•

1
METALLURGICAL PROCESSING John R. Manning

The properties of alloys depend on their processing history. This dependence

arises because processing conditions determine the microstructures and

composition distributions that are developed in an alloy; and these features

in turn determine the alloy properties. The NIST work on metallurgical

processing has as its objective the understanding of these processingmicrostructure -property relations and the development of methods for

measurement, prediction, and control of metallurgical processes.

Work on powder processing, effects of solidification velocities, and nonequilibrium interface processes has continued. In addition, during the past

year, on-going activities related to the mechanical properties of alloys and

their dependence on alloy microstructure were incorporated into the

Metallurgy Division and into this group. The goal of this work is to relate

processing to microstructures to properties. . As a further addition, phase

diagram activities concerned with development of advanced materials such as

metal matrix composites and intermetallics are included as part of the

present report. Process scientists and alloy designers need to know what

alloy phases are possible in order to choose processing paths that will avoid

undesirable phases and produce improved final products.

Collaborations continue with industry, universities and other government

agencies. In cases where NIST has special processing facilities, such as

those on rapid solidification, visiting scientists come to NIST to prepare

special alloys. Studies on metal matrix composites, intermetallics and hot

isostatic pressing are supported by the Office of Naval Research and the

Defense Advanced Research Projects Agency. Studies of directional

solidification and alloy coarsening are being sponsored by the National

Aeronautics and Space Administration. Cooperation continues with the

national steel program for new technology, and an NIST/industry consortium is

developing techniques for intelligent processing during supersonic inert gas

metal atomization using our SIGMA atomization system.

FY 88 Significant Accomplishments

o The Al(matrix) -SiC(f iber) metal matrix composite system was examined

for phase stability in the presence of a liquid aluminum phase.

Transmission electron microscopy measurements were made of intermediate

phases formed at Al-SiC interfaces and interface roughness generated by

diffusion and reaction. Calculations and measurements were made of the

Al-Si-C phase diagram to relate these measurements to equilibrium and

possible non- equilibrium phases.

o High speed holograms (exposure times of 20 ns) and high speed motion

pictures (10,000 frames/s) were used to investigate the operative

disruption mechanisms during inert gas atomization of Sn-Sb and

stainless steel alloys. This is the first application of holography

techniques to metal atomization.

15
o An NIST/Industrial consortium on Metal Powder Atomization was formed to

study particle size control during inert gas atomization. Approximately

twenty 10 Kg batches of 304 stainless steel were atomized to determine the

characteristics of the Supersonic Inert Gas Metal Atomizer (SIGMA) as well

as to test new in-situ particle size measurement techniques.

o The consolidation of metal powders into solid pieces by Hot Isostatic

Pressing (HIP) has been studied for pure copper and for TiAl intermetallic

compounds. The experimental results were compared to theoretical models.

In each case, the models are useful but require further development. For

example, HIP densification of TiAl is rapid at 1000°C but involves

micros tructural changes not included in available theoretical models.

o A theory was formulated to predict the composition, long-range order

parameter, and interfacial undercooling during the rapid solidification of

intermetallic compounds. The theory predicts the solidification velocity

at which an ordered crystalline phase must grow to form disordered

crystal

o A thermodynamic model for u>~phase in Ti- alloys was developed which

permitted the calculation of metastable equilibria with a-Ti phase in

Ti-Nb, Ti-Mo and Ti-V. Ternary phase diagrams were calculated of Nb-Al-0

for the high temperature oxidation program and Ti-Al-Nb for the

intermetallics program.

o A precision elastic and plastic properties data base was established for a

new, weldable high strength steel. The properties were measured in

tension, compression, and shear. The novel steel studied here is

presently making possible a new class of light weight naval vessels and

has significant cost-saving potential in many commercial applications.

o Automated techniques were developed for the quantitative assessment of the

inclusion content of steels. A stereological code was written to convert

the two-dimensional data into three-dimensional information about the

inclusions. This research provides a scientific basis for quantitatively

linking processing to the properties of finished steel products.

o The coarsening of Sn particles in eutectic Pb-Sn liquid was measured

while the samples were being slowly rotated to avoid sedimentation and

agglomeration of particles. For low volume fraction solid samples the

particles coarsen with a temporal law in agreement with that predicted by

theory for the case of constant fluid flow velocity.

o The effect of anisotropic crystal-melt surface tension on the cellular

interface morphologies and the resultant microsegregation patterns which

occur during directional solidification has been calculated. For most

metallic alloys, the calculation, which includes a weakly non-linear

analysis, predicts a solute distribution corresponding to hexagonal nodes

near the onset of cellular growth.

16
o A five-year program to characterize dynamic crack growth and arrest in

pressure vessel steels has been successfully completed. Scientific

achievements include evaluation of brittle crack inertia and

kinetics of plastic zone formation. The data base is being used to

confirm the integrity of pressure vessels in nuclear reactors.

Solid State Processes and Interfaces

J. R. Manning, C. A. Handwerker, S. C. Hardy, J. W. Cahn, J. D. Lee*, and

W. H. Rhee* *

* Guest Scientist - Chonnam National University, Kwangju, Korea

Guest Scientist - Korea Advanced Institute of Science and Technology,

Seoul, Korea

Solid state reactions, especially those at interfaces, are critical in

determining the properties of metal matrix composites, surface modified

alloys, and alloys undergoing coarsening. Topics that are important in the

current NIST work in this area include surface energy effects and the effects

of stresses generated by diffusion at reactive interfaces.

Thermodynamics and Kinetics of Reactions at Non-Equilibrium Interfaces - Interface reactions and interface structures produced by these reactions are

critical in determining the mechanical properties of composite materials.

Resistance of composites to fracture and crack propagation depends strongly

on the degree of bonding, the amount of fiber pull-out, and the structure of

the matrix- fiber interface. The production of interfaces with the "correct"

degree of bonding, a stable interfacial bond, and a morphology that does not

undermine the strength of the reinforcing material will be important in

application of metal-matrix composites as high strength, high stiffness

materials and also will be crucial for high- temperature ceramic -matrix

composites

.

Except under unusual circumstances, the matrix metal and the fiber or

particulate reinforcements will not be in thermodynamic equilibrium when the

two materials are first brought into contact. The system is generally also

far from equilibrium even when the fibers are coated to limit diffusion and

reaction at the matrix- fiber interface. Thus, there is a need to understand

the thermodynamics and kinetics of composite interface reactions, the types

of interface phases and textures that can develop, and ways of controlling

interface properties. To this end, the goal of this work is to provide

guidelines for the prediction and control of interface reactions in the

production and use of composite materials. Three general topics, examined

both theoretically and experimentally, are being investigated: (1)

nucleation and surface energy effects at interfaces, since these will

determine the structure and texture of the fiber-matrix interfaces, (2)

reactions in the Al-SiC system, a model system for practical composites, and

(3) stress effects accompanying diffusion at interfaces, since these stress

effects can strongly influence composite interface morphology and stress

adjacent along the interface.

17
A general theory for the development of nucleation textures has been

developed giving the relationship between the orientations of second phase

particles nucleated at an interface and the surface energies of these phases.

This theory includes anisotropies in all interfacial energies, including the

change in the crystal - subs trate energy with misor ientation . This theory

demonstrates that the orientations of crystals nucleating on a planar

substrate should depend on the equilibrium shape of the crystal and all

anisotropies in the interfacial energies and that minimizing the energy

barrier for nucleation leads to predictions of strong orientation textures

that can change abruptly with small changes in nucleation conditions. This

general theory is applicable both to phases nucleated at solid- liquid

interfaces, such as occur during formation of composites by liquid

infiltration or electrodeposition into a fiber preform, and also, with some

modification, to phases nucleated at solid-solid interfaces.

In addition, transmission electron microscopy (TEM) measurements were made of

interface reactions in Al-SiC, a model composite system, to evaluate the

phases present, the defect population, including dislocations and twins, and

the interface roughness generated by diffusion and reactions. Calculations

and measurements were made of the Al-Si-C phase diagram to relate the TEM

measurements to equilibrium and non-equilibrium phases in this ternary

system. The phase diagram study indicates that the only carbide phase formed

between SiC and Al at temperatures lower than approximately 1000°C is A1a C 3

. The interface roughness and the amount of interpenetration between SiC and

A1a C3 were found to depend strongly on the initial microstructure of the SiC.

Diffusion at an interface generates large coherency stresses and strains when

the lattice parameter is a function of composition. The effects of stresses

generated by diffusion at liquid- solid interfaces have been demonstrated in

experiments in the. Mo -Mi- and the Mo-Ni-Fe systems, in which stresses created

by diffusion perturb originally planar interfaces. In these experiments,

both deposition and dissolution reactions were generated as a result of the

compositionally induced stresses present in the solid phase at Mo(solid)-

Ni( liquid) interfaces. This combination of reactions produces an interfacial

instability and large scale roughening of the interface. Mechanisms for the

initiation of the instability have been developed based on the thermodynamics

of stressed solids and the time evolution of the instability has been

analyzed, from initiation to final flattening of the interface after stress

relaxation occurs in the diffusion zone.

When the stresses caused by diffusion are high in a solid- liquid system, a

grain size refinement of the original solid can occur either by the

initiation of the instability followed by pinch-off of the precipitating

regions or by nucleation of stress -free grains in a matrix stressed by

diffusion followed by wetting of the newly created grain boundaries by

liquid. Recrystallization/grain size refinement has the potential for

producing small particle sizes that are difficult to attain by other methods

as well as the potential for causing catastrophic dissolution of reinforcing

materials in composites, even when the reinforcing material is a single

crystal

18
Ostwald Ripening of Solid-Liquid Mixtures - Alloy coarsening and Ostwald

ripening are driven by the decrease in surface energy that can be achieved

from, for example, the growth of large precipitates at the expense of smaller

precipitates. Studies of the coarsening of Pb-Sn solid- liquid mixtures are

being used as models to study this type of process under conditions where

coarsening occurs rapidly enough for efficient measurement and under wellspecified conditions which can be readily compared with theory.

Coarsening measurements in solid- liquid systems are normally made with high

volume fraction solid samples where the development of a skeletal structure

stabilizes the particles and prevents sedimentation driven by density

differences. During this past year we have been developing a sample rotation

technique which permits measurements in low volume fraction solid samples.

In this technique, a disc- shaped sample is rotated in the vertical plane so

that the particles describe circular orbits as they settle. Although the

coarsening studies are complicated by the development of particle clusters,

the average particle radius seems to increase initially with a temporal

exponent of 1/2 as predicted for Stokes settling. At long coarsening times,

most of the particles are agglomorated into clusters. The buoyancy forces on

these clusters are so large they cannot describe orbits in the liquid but

remain stationary as the liquid rotates past them. Although the fluid flow

in the sample during rotation is not well understood, the average particle

diameter increases with a temporal exponent of 3/8 in this case which is the

result predicted by theory for constant flow velocity.

Powder Processing

S. D. Ridder, F. S. Biancaniello , R. J. Schaefer, R. L. Parke, P. A. Boyer

An NIST/IndustriaL c ons.gr tium -on-powder processing was initiated and has

begun a multi-disciplinary study on automation of inert gas atomization.

Research groups from NIST aided by the financial and scientific assistance of

Crucible Materials, General Electric, and Hoeganaes Corp. have combined to

develop sensors and control systems needed to automate the atomization

process. The NIST research groups include the Intelligent Control Systems

Group of the Factory Automation Systems Division, Fluid Flow and High

Temperature Reacting Flows Groups of the Chemical Process Metrology Division

and the Metallurgical Processing Group of the Metallurgy Division. The

Supersonic Inert Gas Metal Atomizer (SIGMA) in the Metals Processing

Laboratory has been chosen as the development tool for this consortium.

The project was divided into four sub tasks, each to be completed

concurrently. (1) In-situ particle size sensor development using

Fraunhoffer diffraction has progressed to successfully monitor particle size

at the exit region of the SIGMA facility. Current efforts are aimed at

improving the performance of the computer used to transform diffracted light

intensity information into particle size distribution and continuing

modifications to the viewports used to monitor the powder flow. Assistance

on this subtask has been provided by the High Temperature Reacting Flows

Group. (2) Process modelling studies have commenced using a specially

constructed supersonic flow test bench. This facility, designed and operated

jointly by the Metallurgical Processing Group and the Fluid Flow Group,

duplicates the high pressure plumbing used in the SIGMA system and provides

19
access to the supersonic gas jets for precise measurements of temperature and

pressure profiles in the supersonic gas jets. Figure 1 shows the axial gas

velocity and sound velocity distributions calculated from the static

pressure, stagnation pressure, and stagnation temperatures measured on this

test bench. These intrusive sensor studies have been augmented with nonintrusive photographic analysis of gas and gas -liquid flows. Schlieren and

shadowgraph density wave imaging have been used to photograph the shock and

expansion waves in both gas only and gas-water supersonic flow. In addition,

twenty ns exposure holography and 10,000 fps cinematography were used to

capture the actual disruption phenomena during water and metal atomization.

The results of these and future flow studies will be used to improve

atomization efficiency and to determine the best process control strategy.

(3) Running concurrently with the previously mentioned sub -tasks is a

process parameterization study which, when completed, will delineate the

effect of each process variable on the final particle size distribution.

Numerous atomization runs have been completed in a variety of metal alloys

including Sn, Al , Cu, Fe, and Ni-based systems. (4) Researchers from the

Intelligent Control Systems Group have been enlisted to aid in the

construction of the process controller itself. A PC-based system has been

chosen to ensure adaptability to other metal atomizers with minimal expense.

Hot Isostatic Pressing (HIP) is an important method for consolidating metal

powders into solid parts. The powder is enclosed in a gas-tight can and

heated in an argon- filled pressure vessel. In the past, the pressure,

temperature, and time required to attain full densification of the powder

have been determined mostly by expensive empirical tests. Now, studies of

the kinetics of HIP processes being carried out in a joint project with the

Advanced Sensing Group are leading the way toward much more sophisticated

control of HIP operations.

Powder samples encapsulated in cylindrical cans have been subjected to a

range of temperatures and pressures in a HIP system, and sensors developed by

the Advanced Sensing Group have been used to determine their diameter as a

function of time. The results are compared to the predictions of theoretical

models of the powder densification process and are used to refine some of the

parameters of the model or to indicate areas in which the theoretical model

requires further development. The project, jointly sponsored by DARPA and

NIST, is devoting attention specifically to titanium aluminides, which

undergo complex microstructural changes during the consolidation process.

The objective of the project is to obtain full densification of the powders

while maintaining control over the microstructural changes. Experiments to

date have indicated that the metastable phase content of rapidly solidified

titanium aluminides transforms to a more equilibrated phase content at

temperatures below those at which significant densification occurs.

Microstructures and Properties of Steel

R. J. Fields, R. deWit, S. R. Low, III, D. E. Harne , R. C. Reno, R. D.

J iggetts

Quantitative Metallography of Steel Microstructures - The utility of steel

depends on its mechanical behavior, formability, and other performance

20
characteristics such as surface finish and paintability . These properties

are determined by microstructures that result from processing. Quantitative

modelling of processing effects on performance require quantitative

assessments of microstructural characteristics. In this research, attention

was focussed on measuring inclusions and on grain size and shape

distributions. The research has progressed along two paths: (1) development

of standardized preparation and (2-dimensional) measurement techniques for

inclusions and grains, and (2) stereological methods for deducing the 3-

dimensional nature of the microstructure from the 2-dimensional measurements.

The objective of this research is to provide a theoretical and experimental

basis for quantitative stereological analyses of steel microstructures

prepared by standardized metallographic techniques. This work provides a quantitative means of relating processing parameters, microstructures, and

the performance of finished steel products.

Standardized procedures for preparing and measuring inclusions have been

established. A computerized, automated microscope has been programmed to

measure and collect the pertinent data on inclusions from the prepared

samples. Application of new stereological analysis techniques to an

artificial 2 -dimensional inclusion distribution including prolate and oblate

spheroids was successful, and we have applied it to inclusions measured on

planar sections of 304 stainless steel without difficulty. This work is now

being extended to analyze grain size and shape distributions, i.e., spacefilling particles as opposed to dispersed particles like inclusions.

Experimentally, in collaboration with the Fracture and Deformation Division,

studies have been initiated on the effect of thermomechanical processing

(TMP) on austenite grain size and shape distribution.

Wide-Plate Crack-Arrest Testing - Crack arrest refers to the sudden stopping

of a fast fracture. Crack velocities and arrest toughness must be known to

prevent disastrous failure of large structures, such as nuclear pressure

vessels. In work requested by the Nuclear Regulatory Commission, we have

used new strain-gage techniques and a 53 MN (12 x 10 6 lbf) tensile testing

machine to measure these values for some of the largest steel specimens ever

tested. Very large specimens, typically 10 to 15 cm (4 to 6 inches) thick

and a meter square, are required to avoid intractable complications due to

reflected stress waves during the fracture event. Tests of 16 single-edgecrack tensile specimens in a thermal gradient have now been completed. We

have obtained crack arrest data at 115°C above the nil-ductility temperature,

the highest temperature at which arrest has been achieved.

Of the four tests completed in the past fiscal year, two were performed on

as-received A533B steel and two on a steel that had been heat-treated to

simulate radiation embrittlement. Results showed that brittle fracture could

occur at temperatures above the onset of ductile behavior as determined by

traditional impact testing. Furthermore, arrest occurred at extraordinarily

high values of applied stress - intensity factor. Research continues on

identifying the physical or atomistic toughening mechanisms that permit a sharp cleavage crack to support such high crack driving forces. In addition,

the data base resulting from these tests is being compiled in a personal

computer accessible form for convenient dissemination to collaborators and

other interested parties.

21
Mechanical Properties of High-Strength Low Alloy Steel - Two new highstrength low-alloy (HSLA) steels have been developed recently by U.S.

industry. These are both chemical modifications of ASTM A710 steel. One has

a nominal yield strength of 80 ksi and the other 100 ksi. They are both

extremely tough and weldable. We have established a precision data base for

these two alloys to facilitate the comparison of these steels with existing

alloys and to aid in the design of structures and components fabricated from

them. Present and future applications of these alloys include naval vessels,

off-shore structures, railroad tank cars, and other commercial applications

where high strength, toughness, and weldability are required. The properties

determined include the elastic, plastic, and fracture properties measured in

tension, compression, and shear. Precision true s tress - strain curves were

also generated up to the point of instability (i.e., necking, barrelling, or

buckling) in the above three loading modes.

Controlled Solidification

S. R. Corieli, R. J. Schaefer, and J. R. Manning

In this research, the fluid flow, solute segregation, and interface

morphologies which occur during solidification are being studied. In

collaboration with G. B. McFadden, R. F. Boisvert, and L. N. Brush of the

NIST Center of Computing and Applied Mathematics, R. F. Sekerka of CarnegieMellon University, J. I. D. Alexander of the University of Alabama in

Huntsville, A. A. Wheeler of the University of Bristol, and D. T. J. Hurle of

the Royal Signals and Radar Establishment, convection and interface stability

during alloy solidification have been analyzed and modelled. The resulting

predictive models can be used to guide alloy designers in choosing processing

conditions that will provide optimum properties of the solidified materials,

for example, in providing homogeneous material needed for electronic

applications and in predicting the type of alloy segregation expected during

the continuous casting of steel. A theory of dendritic growth developed by

Kurz , Trivedi , and colleagues [Acta Met. 34, 823-830 (1986)] for binary

alloys has been extended to multicomponent alloys, including steel. The

model describes the columnar (directional) growth of dendrites. The radius

of the dendrite tip is obtained from the marginal wavelength for the

stability of a planar interface growing at a given velocity with a specified

temperature gradient in the liquid. The solute field in the vicinity of the

dendrite tip is obtained from the Ivantsov solution for a parabolic dendrite.

The theory predicts the radius of dendrite tip, the concentration of solutes

at the dendrite tip, and the temperature of the dendrite tip as a function of

the processing conditions. A computer program is being written to calculate

these quantities for multicomponent alloys appropriate to the solidification

of steel.

Morphological stability theory predicts the conditions for which a planar

crystal-melt interface is unstable for directional solidification of a binary

alloy at constant velocity. For conditions near the onset of instability, a

three-dimensional weakly nonlinear analysis has been carried out to second

order in the interface deformation taking into account the anisotropy of the

crystal-melt surface tension. The results of this analysis allows the

22
prediction of interface morphologies and solute segregation patterns near the

onset of cellular growth. Growth of a cubic crystal in the [001], [Oil], and

[111] directions has been considered. For a typical metallic alloy with a solute distribution coefficient less than unity, these calculations indicate

that the solute distribution pattern should correspond to hexagonal nodes

rather than hexagonal cells.

During directional solidification of a binary alloy at constant velocity,

buoyancy -driven flow may occur due to solute gradients generated by rejection

of solute at the crystal-melt interface. Numerical calculations of the

solute and fluid flow fields in the melt have been carried out using finite

differences in a two-dimensional, time - dependent model that assumes a planar

crystal-melt interface and allows time - dependent gravitational accelerations

(for example, vibration of the sample). The container walls are rigid and

perfectly insulating to solute. For constant gravitational accelerations, as

the solutal Rayleigh number (dimensionless solute gradient) is varied,

multiple steady- states and time - dependent states may occur. The bifurcation

from the quiescent state may be subcritical or transcritical , depending on

the aspect ratio of the container. The solute distribution in the solidified

material is obtained as a function of processing conditions.

Linear stability analyses are being applied to problems associated with the

morphology of the crystal-melt interface. The effect of a two-dimensional

stagnation flow on double diffusive and morphological instability has been

calculated. The flow stabilizes the system with respect to perturbations

that are perpendicular to the flow; the double diffusive instability is

significantly reduced by the flow. The role of buoyancy on morphological

stability during directional solidification vertically upwards for the case

of rejection of a heavier solute at the crystal-melt interface will be

investigated. Preliminary results indicate that for certain alloys a long

wavelength instability can occur.

Physical Metallurgy and Processing of Advanced Alloys

W. J. Boettinger, L. A. Bendersky, F. S. Biancaniello , B. P. Burton, J. W.

Cahn, U. R. Kattner

The development of new alloys with significant improvements in strength,

density, and operating temperature requires an examination of new processing

methods and new classes of alloys not normally employed in conventional

metallurgical practice. Research is directed toward the examination of

processing paths involving precursor metastable phases to produce stable twophase structures after decomposition. For example, the formation of ductile

second phase particles in interme tallies has the potential of increasing the

toughness of these materials. Since equilibrium phase diagrams suggest only

limited opportunities for precipitation from supersaturated interme tallic

phases by conventional heat treatment, the possibility of extending the range

of solubility of intermetallics by rapid solidification is being examined.

Similarly large volume fractions of small, hard dispersoids can be formed in

aluminum-base alloys by the same approach. Principles required to manipulate

alloy microstructure by these methods are being sought.

23
Intermetallic High Temperature Alloys - Because of their high melting

temperatures and low densities, many intermetallic compounds show promise for

a generation of advanced alloys which may span the gap between ductile

metallic alloys and brittle ceramic materials. Recently the application of

rapid solidification and other new processing techniques (such as plasma

deposition) to intermetallic alloys has stimulated a renewed effort in the

development of high temperature intermetallics for structural application.

In this year's research at NIST, it was established that an extension of the

composition range of intermetallic compounds by rapid solidification was only

possible when the compound was not too strongly ordered; i.e., line compounds

do not respond significantly to rapid solidification. A theory was developed

to predict the composition, interface temperature and long-range order

parameter of intermetallic compounds as a function of solidification rate

using an analysis of the interdiffusion across the liquid solid interface

between a liquid phase and a solid phase composed of two sublattices. With

increasing interface velocity the theory predicts a transition from the

solidification of a phase with equilibrium long-range order parameter and

with equilibrium solute partitioning to the solidification of a disordered

crystalline phase with the same composition as the liquid. The critical

velocities required to effect these transitions depends on the free energy

function of the solid phase and thus are closely related to the strength of

ordering of the solid phase. Some results are shown in Figure 2.

The decomposition of metastable microstructures formed by rapid

solidification have been studied in NiAl-Ni2 TiAl and NiTi-Ni2 TiAl eutectic

alloys. Under ordinary processing conditions these alloys contain nearly

equal volume fractions of a B2 phase based on NiTi or NiAl and a Heusler

(L2 1 ) phase based on Ni2 TiAl. Following rapid solidification by melt

spinning the alloy is metastable single phase Heusler. During heat

treatment, the isotropic APB structure disappears and is replaced by an array

of coherent cuboidal precipitates of the Heusler phase in the B2 matrix.

This structure, which often has excellent mechanical properties, can not be

made in this alloy without the rapid solidification processing. The effect

of the coherency strain due to the 1.6% lattice parameter mismatch between

the B2 and Heusler phases on the formation of the cuboid structure has also

been detailed (L. A. Bendersky, P„ W. Voorhees, W. J. Boettinger, and W. C.

Johnson, ScriptaMet. 22 (1988) 1029-1034).

Titanium aiuminides (Ti3 Al and TiAl) containing Nb additions are currently

being studied in many laboratories for potential high temperature service.

These alloys may be processed conventionally or by rapid solidification

either as a monolithic or a composite matrix material. However, the phase

equilibria in the Ti-Al-Nb system are poorly understood. Microstructural

studies have been conducted using TEM on heat treated alloys. The

compositions surround the composition Ti2 AlNb. All of the alloys contain

large volume fractions of B2 or related phases when cooled at -400 K/min from

1400°C. According to their fine scale of microstructure and crystallographic

features, the related phases are the product of solid state transformation

during cooling. At 1400°C all alloys are in the B2 (or possibly BCC) phase

field. The presence of BCC or B2 phases may have significant impact on the

toughness of these alloys.

24
For Ti-37.5 at% Al-12.5 at% Nb , the large grains of B2 phase stabilized at

1400°C decomposed during cooling to a single phase consisting of small (~1

Hm) domains of a phase with a hexagonal Bravais lattice (a = .42 nm, c = .58

nm) . Four rotational variants, related to the cubic phase by <11 1>C |

| [ 001

]

H orientation relationship, were observed. Each domain itself consists of

three variants of translational antiphase domains. This phase is related to

the w-phase found in the Ti-Nb binary system.

In order to provide a framework for the experimental results on Ti-Al-Nb

alloys and interpolation or extrapolation of data to other temperatures, a

calculation of the Ti-Al-Nb ternary phase diagram was undertaken using the

THERMOCALC DATABANK system. Some results are shown in Figure 3. The

stability ranges of the phases were adjusted to match the experimental data

obtained above and at the University of Wisconsin by J . H. Perepezko and

Y. A. Chang. In the calculations of the binary systems, which are required

before the ternary can be calculated, the liquid and terminal phases were

described as sub-regular solutions. The intermetallic compounds in the Nb-Al

and Ti-Al were described with the Wagner- Schotky model, where compounds are

considered to consist of different sublattices allowing substitutional

solutions on each of these sublattices. The Ti-Nb binary was calculated by

D. L. Moffat and U. R. Kattner (Met. Trans. A (1988)) and includes the

metastable w-phase which seems to appear in an ordered variant in the ternary

system. For the calculation of the ternary Ti-Al-Nb system, all phases must

be allowed to have ternary ranges of homogeneity, which means that WagnerSchottky phases must be modeled as metastable phases for the two other binary

systems. The Gibbs energies of these metastable phases have been adjusted to

obtain a match of the calculated diagram with the experimental data. Results

from this calculation were presented at the CALPHAD XVII Conference.

A limitation of the THERMOCALC approach to calculation of phase diagrams

involving order-disorder transitions is the use of the sublattice model to

represent the ordered phases. The cluster variation method (CVM) , which

includes crystallographic aspects of order, is being extended to ternary BCC

ordered phases which occur in the Ni-Ti-Al and Ti-Al-Nb as well as other

systems. A code has been written for the tetrahedron approximation in the e- G mode. Thus phase relations between A2 , B2 , B32, D03 , and L2 X phases can be

treated. Both short- and long-range interactions may be considered. In most

cases it is sufficient to consider only first- and second-neighbor pairwise

interactions, but there are exceptions. For example, in the pseudobinary

NiAl-NiTi (and therefore the ternary Ni-Al-Ti) it is necessary to invoke

either: (1) first- through third-neighbor pair interactions, or (2) longrange "elastic" contributions, to successfully model the observed subsolidus

phase relations. Another application is the Fe-rich regions of the Fe-Al

( iron-aluminide) and Fe-Si systems which must be treated as ternaries (FetFei-Al and Fet-Fel-Si) in order to model magnetic effects.

Aluminum-base Alloys - Aluminum alloys containing large additions (-10%) of

elements with limited (<3%) equilibrium solubility form one of the new

classes of alloys made possible by rapid solidification. In previous

research on Al-Fe-Si alloys, the possibility of forming microstructures with

fine distribution of dispersoids was demonstrated. This year, the

micros true tural response and the sequence of phase transformations during

thermal annealing was studied by means of transmission electron microscopy

25
and differential scanning calorimetry. First, the amorphous spherulites

formed in the Al matrix by rapid solidification transform (at -380°C) to the

complex a(AlFeSi) cubic phase. This transformation could be promoted by the

similarity in local structure (icosahedral clusters) of both phases. At

higher temperature (~430°C) , the cubic a(AlFeSi) phase transforms by ordering

to a trigonal phase (two modifications, rhombohedral a' and trigonal a", were

found) . Only at higher temperature (~500°C) did phases known to be

equilibrium (monoclinic Al 13 Fe A and hexagonal aH ) replace the lower

temperature phases

Since the lower temperature phases have a distribution and size desirable for

good mechanical properties, an attempt was undertaken to stabilize these

phases by adding a fourth element. Addition of Mn was found to be

successful. The Al-Fe-Mn-Si alloys retain a fine distribution of a(AlFeMnSi)

phase particles even after very high temperature annealing (550°C ~0.9Tm Al)

One of the quaternary alloys, Al-5Fe-5Mn-5Si (wt%) was successfully atomized

using the NIST atomizer. Preliminary study of the powder microstructure

shows the presence of desirable fine distribution of the a(AlFeMnSi) phase.

Work on these alloys will continue.

26
(Dcn

0 12 3 4 5 6 7

Distance From Nozzle/Interjet Diameter

8

Figure 1. The upper plot shows the measured axial distributions of the static and

stagnation pressure as well as Mach number produced by the die used in the

SIGMA atomizer. These measured values were used to compute the velocity

distributions shown in the lower plot. Note that gas velocities in excess

of 400 m/s are achieved.

Figure 2. Prediction of non-equilibrium kinetic theory for the rapid solidification

of an intermetallic compound. (a) Long range order parameter, rj, as a function of dimensionless solidification velocity, V/VD

. Above

V/VD = 10" 1

, only a disordered (r/ = 0) crystal can form. (b) Composition

of the liquid, x^, at the interface as a function of velocity, for a

B

solid composition 0.48 when the congruent point of the intermetallic

compound is 0,50. The dashed curve is an unstable solution of the theory

at low velocity corresponding to rj = 0.

27
1

I

1 .

0

^ 0.6

'^ 0.4

A15 0.2 0.4

MOLE-FRACTION PL

Figure 3. Preliminary calculation of the Ti-Al-Nb ternary system at 1400°C. The

ternary phases are absent.

28
ADVANCED SENSING Haydn N. G. Wadley

The mission of the Advanced Sensing Group is to enhance the measurement

science of noninvasive sensing methods and to apply them to the needs of

materials science and engineering. These needs fall usually into two

classes: methods for in situ observation of materials phenomena and

techniques for sensing during process control.

The Group has aggressively moved into several research news areas this past

year, while still maintaining its ongoing collaborative programs with the

American Iron and Steel Institute and the Aluminum Association (this latter

with partial support from the ONDE) , and the research on interfaces in metal

matrix composites.

Most visible of the new programs is a demonstration of DARPA' s intelligent

processing of materials (IPM) concept for the hot isostatic pressing of

intermetallic composites. This DARPA funded program couples researchers in

Metallurgy Division's Advanced Sensing and Processing Groups with the BDM

Corporation, and the Universities of Cambridge (England) and Lulea (Sweden)

to develop process sensing methods, validated process models and new control

concepts incorporating artificial intelligence methods. Other important new

work on process sensing has teamed the Advance Sensing Group with General

Electric (Aircraft Engines Division) under NRL/DARPA/GE support to explore

microstructure sensing during Rapid Solidification Plasma Deposition (RSPD)

.

The Group has also been active in the new field of high Tc superconductivity

where, with DARPA support, scoping studies of potential sensor methodologies

have been initiated. Finally, the Applied and Computational Mathematics

Program at DARPA has coupled NIST researchers in materials science with

research mathematicians at Georgia Institute of Technology and the University

of California at Los Angeles to model microstructure evolution using

nonlinear methods emerging from the mathematics community.

Meanwhile, the ongoing collaborative programs with the AISI and Aluminum

Association have each made substantial progress and several important

milestones have been reached. The AISI/NIST program on internal temperature

sensing has achieved the first imaging of a liquid- solid interface in a metal

undergoing solidification. The ultrasonic technique used is an extension of

the earlier developed method for measuring the internal temperature field in

solid bodies. In related research, DOE funded researchers from Battelle

Pacific Northwest Laboratory, Magnasonics, and AISI member companies have

recently successfully tested the ultrasonic approach at ARMCO's specialty

steel continuous caster at Baltimore. Thus, all the initial milestones for

demonstrating feasibility have now been achieved. Future work looks toward

the integration of this technique with process modeling of continuous

casting.

The collaborative program with the Aluminum Association is exploring the use

of electromagnetic (eddy current) methods to determine the temperature of

aluminum during extrusion processing. Continued Aluminum Association support

of Research Associate Michael Mester has had a major favorable impact on

progress. An encircling coil technique has been successfully developed and

29
tested in an extrusion mill on bar and hollow sections. A new transmission

technique is under test in the laboratory for use in other more complex

geometries; it is scheduled to be evaluated during October 1988 .

In the metal matrix composites area, we have completed development of an

in situ test method for determining the strength of fibers and fiber/matrix

interfaces in metal matrix composites. The technique utilizes acoustic

emission to locate fiber fractures to ±100/im coupled with careful

micromechanical measurements and a simple shear lag analysis. The technique

is now being used to gain insight into the effect of process variables upon

interface strength in aluminum- silicon carbide composites.

During FY 88 collaborations and interactions with industry, academia, and

other government agencies have increased dramatically. Several cooperative

programs have been started with General Electric and we are interacting with

BDM, Pratt, and Whitney and Martin Marietta. New grants have been started

with Prof. M. F. Ashby of Cambridge University (England), Prof. M. Fox and I.

Hulthage at Carnegie Mellon University, Prof. Shui-Nee Chow at Georgia

Institute of Technology and Prof. R. Chapman at George Mason University. An

industry/academia consortium of researchers interested in hot isostatic

pressing has been formed as part of the intelligent processing program. A

Workshop on Modeling at the Greenbriar, West Virginia was co-organized with

DARPA during September. Haydn Wadley now serves as Secretary and co-chairman

of Program Planning Committee of the recently formed Materials Design and

Manufacturing Division of AIME-TMS.

FY 88 Significant Accomplishments

o An eddy current method for sensing metal temperature during extrusion

processing has been developed. A simple encircling coil technique has

been successfully evaluated in plant trials on simple shapes of circular

or square cross section (solid and hollow) . A two coil transmission

technique has been tested in the laboratory for more complex geometries.

o A sensor for determining density during hot isostatic pressing has been

perfected and used to evaluate densificaiton mechanisms of a2 +7 phase

titanium aluminides . The data has been used to develop a HIP mechanism

map for TiAl.

o An ultrasonic methodology has been developed for mapping the liquidsolid interface in metals undergoing solidification. In aluminum,

precision of +1 mm has been obtained.

o A new test method for in situ determination of fiber and interface

strengths in metal matrix composites has been perfected and used to

explore the role of fiber coatings and liquid metal contact in aluminumsilicon carbide composites.

o An ultrasonic study has been performed in the YBa2 Cu3 07

. x high Tc superconductor at cryogenic temperatures and large effects upon velocity

and attenuation observed. These have been linked to a low temperature

first order phase transition -- possibly magnetic in origin.

30
Design/Redesign of Process Pathways

Haydn N. G. Wadley, Mark Fox*, Ingemar Hulthage*, and Dan Backman**

* Carnegie Mellon University

** General Electric Company

Intelligent processing of materials concepts for many of the process steps

used in powder metallurgy (see Figure 1) are now being explored. Common to

each step is the development of experimentally validated predictive process

models and knowledge bases and techniques (some based on Artificial

Intelligence) for their interrogation. To date, it has been the intent to

use this resource to control a single process step. In this DARPA funded

effort, researchers at NIST, Carnegie Mellon's Robotics Institute, and

General Electric are exploring the possibility of these process step

simulators with emerging artificial intelligence methods for optimal

design/redesign of a process path aimed to achieve a singular "goal state"

combination of properties.

Interface Characterization in Metal-Matrix Composites

E. Drescher-Krasicka* , John A. Simmons, and Haydn N. G. Wadley

* Guest Scientist, Johns Hopkins University, Baltimore, MD

During melt processing of metal matrix composites opportunities arise for the

formation of new phases at the metal-reinforcement interface. We are

exploring the possible use of an ultrasonic method for observing the

interface zone ("interphase"). In earlier work, our experiments identified

the existence of interface waves at the cylindrical interface of a fiber

reinforced composite. The analysis of the detailed structure of radial axial

(leaky) modes in an isotropic clad rod has now been completed and shown to be

in excellent agreement with these earlier experiments. An example of this

agreement is illustrated in the Figure 2 showing the predicted and measured

dispersion curves for a particular leaky mode in the Al/SiC system. We find

the class of non- attenuating guided modes in a clad rod system is restricted

to those materials where the shear modulus of the rod is less than that of

the cladding. In all other systems a mode will leak energy from the rod into

the cladding.

Over a large range of elastic parameters, the radical-axial wave modes in a

clad rod system, which break down into four families (three of which are

leaky or divergent) , can be correlated with the modes of the bare elastic

rod. In addition to these rod-correlated modes, the only other modes that

were found were correlated to the limited number of "tunnel" modes in a

cladding without a rod present.

31
We have found that the cylindrical geometry of the clad rod system produces a

rich and dispersive structure for the leaky mode families and that, depending

on the particular mode and frequency, analysis of the flow of energy reveals

information about both the rod and the cladding.

This analysis was carried out using the detailed energy velocity field which

generalizes the concept of group velocity. It was shown that by following

the Poynting vector fields describing the energy flow, a lacuna can be

expected after the startup of a leaky wave, and that the generator of this

cone -like lacuna, after tracing a curved path near the interface due to the

interference of the two components of the leaky wave, becomes a straight line

inclined at some angle to the rod axis. Because of the interference pattern

near the interface, the edge of the lacuna of a leaky mode will shift from

its expected position estimated from the asymptotic leakage angle of the

mode. This shift, analogous to similar shifts found in optics and in

acoustics, has been shown to be obtainable directly by following the energy

flow pattern. In some leaky waves, the energy pattern actually reverses

itself and flows backwards; if this occurs asymptotically in the cladding,

the leaky waves are backward leaking.

In addition to the complex patterns found in leaky waves, the energy velocity

field displays the interference between plane and/or inhomogeneous waves near

a plane interface. This pattern differs from the averaged energy flow, given

by the group velocity, even in bare rods; and for clad rod systems possessing

guided modes, the energy velocity at large distances from the interface is

equal to the phase velocity of the cladding, not the group velocity of the

mode

If the structure near the interface zone is more complex, i.e. if the elastic

constants vary- with r and with—frequency w , most of the methods developed

herein can, we believe, be extended to describe the leaky modes in that

structure. Among the modes of such a system one can expect to find some

which are sensitive to the elastic structure of the interface zone.

Torsional sensitivity can be included by extending the above analysis to 6 - dependent modes. In such cases the particle trajectories will no longer be

planar ellipses but will follow slightly more complicated three dimensional

paths. Anisotropy in the direction of the rod axis can also be included for

the clad rod system, but more complex anisotropies can only be treated in the

context of the planar interface using the type of formulation described in

this study.

Test Methods for Interface Strength of Metal Matrix Composites

R. B. Clough, A. Manor*, Haydn N. G. Wadley and F. S. Biancaniello

* Guest Scientist, Armament Deveopment Authority, Israel

Acoustic emission and micromechanical techniques are being used to study the

microdynamics of interfacial failure and fiber fracture in single

crystal/single fiber Al/SiC metal matrix composites. These are Bridgmangrown in the form of dumbbell -shaped tensile specimens. Two different growth

rates and SiC fibers (provided by AVCO-Textron) with either carbon-rich or

32
untreated surfaces are used to study the effects of processing path and fiber

surface treatment on fiber and interfaciai strengths. To do so, it is

necessary to know the fiber segment lengths. Using conical piezoelectric

sensors mounted at each end, the specimens are calibrated for emission source

position using a pulsed Nd-YAG laser. Fiber and interfaciai fractures are

then located during tensile tests to within ± 100 /im, /z(l-10% of the fiber

segment lengths) and subsequently verified by metallographic sectioning.

Higher accuracies of ± 30 ^m are obtainable by better noise-suppression

techniques

.

A micromechanical analysis has been developed, taking into account the

mechanics of the test machine, to calculate the fiber strengths from the

magnitudes of the load drops which occur on fiber fracture. A statistical

model of fracture, combining a Weibull model that includes the tensile stress

distribution from a shear lag analysis, has also been developed and used to

characterize the fracture process. The results show that both fiber and

interfaciai strength always decrease with exposure time in the melt. The

carbonizing surface treatment inhibits degradation of fiber strength by the

melt through the rapid formation of a protective diffusion barrier of A1 a C3. This barrier, at the same time, reduces the interfaciai strength. The

combination of high fiber and low interface strengths is generally thought to

increase resistance to transverse cracking by first blunting the advancing

crack tip with a shear microfracture at the fiber interface and then by

increasing pull-out toughness by frictional sliding of the interface as the

transverse crack passes through. Interfaciai shear fractures were observed

at the ends of fiber segments, which make these types of specimens also ideal

for further testing of interfaciai microfracture theories.

Eddy Current Sensing - Temperature Measurement of Aluminum Extrusion

Processing

A. H. Kahn, M. L. Hester*, and Haydn N. G. Wadley

* Research Associate, The Aluminum Association

The joint project with the Aluminum Association for the development of eddy

current sensing of electrical conductivity for the measurement of temperature

has progressed with the design and construction of a through transmission

sensor suitable for plant testing. In the previous year (1986-1987), a

cylindrical two-coil surround system suitable for examining rods and tubes

was designed, constructed, and tested successfully. The present design

effort has been directed toward making the system applicable to the

measurement of temperature in more complex extended shapes such as

flatstrips, I-beams, and V-channels. These shapes all present cross-sections

with appreciable regions which are flat and thin. These are heat tested by

using transmit and receive coils placed on opposite sides o the flat region

of the extrusion.

The electronic equipment is the same as that used for the surround coil

system described in the previous annual report (NBSIR- 87 - 3615 ; 59). The new

coil system, fitted into a canister and ready to be installed in an extrusion

33
press, is shown in Figure 3. In this particular application two extruded

I-beam shapes will pass horizontally through the two channels; the sensor

will detect the temperature of the product in the upper channel only. The

transient coil is located in the upper part of the channel; the receive coil

is recessed in the horizontal web. Electrical leads and water cooling tubes

are visible. The plant test will be carried out in the fourth quarters of

1988.

Modeling the Evolution of Intermetallic Microstructure

J. W. Cahn, John A. Simmons, Haydn N. G. Wadley, Shui-Nee Chow*, J. K. Hale*

and S . Osher**

* Center for Dynamical Systems, Georgia Institute of Technology

** Department of Mathematics , UCLA

This new NIST/DARPA project addresses the application of emerging methods

from the mathematical theory of dynamical systems to predict the evolution of

microstructure in advanced intermetallic alloys. The goals of this program

include

o Solution of previously intractable materials science problems using

new. mathematical algorithms from computational algebraic topology,

nonlinear partial differential equations and chaos theory.

o Development of new mathematical formalisms incorporating global

stress and stochastic f luctuation- type variables to extend current

reaction diffusion equations for multicomponent alloy systems.

o Development of image analysis techniques to characterize

microstructure evolution.

o Design and implementation of experiments to critically evaluate

theoretical models and their predictions.

The kinetics of the evolution of phases and their microstructural morphology

occurring during solidification and subsequent annealing of metallic alloys

are only qualitatively understood for multicomponent alloy systems. The

first approximation to modeling this evolution will be carried out using the

free energy function and generalized forms of the Cahn-Hilliard equation, but

more advanced methods for determining the system propagator, such as path

probability and transient time correlation methods will also be studied.

Binary alloy systems containing titanium and aluminum, will be targeted and

extension to ternaries containing nickel (or niobium) will also be

investigated.

The crystallography of these ternary structures can be visualized in terms of

four sublattices- -each sublattice consisting of alternate sites on each of

the two interpenetrating cubic sublattices making a bcc structure. Each of

these four sublattices contains one- fourth of the atomic sites of the bcc

structure. The simplest (Bragg-Williams) long range order model for this

34
system, leading to the reaction diffusion equation describing order

ingredients, is then given by specifying the fraction of each of these

sublattices occupied, respectively, by nickel, titanium and aluminum atoms- -a

total of twelve parameters, c i ^

, the concentration of the i ' th species on the

j ' th lattice. The free energy is then a functional of these twelve field and

the temperature field. Knowing the (conserved) concentrations of nickel,

titanium and aluminum atoms, together with the fraction of atoms on each of

the fixed sublattices gives a total of 4+3 - 1=6 constraining relations

leaving 6 (non-conserved) order quantities to describe the system. The

reaction-diffusion equations governing this system can be derived in a similar fashion to the Cahn-Hilliard equation for systems with one ordering

parameter and are of the form:

Bc lj /dt = Dijkl Ack +fu (c)

where f(c) describes the cross-linking (or reaction) of species between

sublattices and Di j ki is an interdiffusion coefficient. This approximation

can be improved by adding vacancies as another species and making the

interdiffusion coefficients dependent on the concentrations. Still more

accurate models are obtained by considering short range clusters of atoms,

but the propagators for these variables have not yet been converted to

reaction diffusion form.

The Cahn-Hilliard equations will be converted to ordinary differential

equations using the method of inertial manifolds and the topological

dependence of the solution forms on the initial conditions will be studied by

Professors Chow and Hale. Computer models for describing microstructural

evolution will then be developed in cooperation with NIST and compared with

experiments carried out at NIST. ("Rapid Solidification and Ordering of B2

and L2\ Phases in the NiAl-NiTi Systems," W. J. Boettinger, L. A. Bendersky,

F. S. Biancaniello , J. W. Cahn, Proceedings of RQ6 , Montreal, August. 1987 to

appear in Mat. Sci. and Eng., 1988). Analysis of microstructures obtained

will be developed in collaboration with Professor Osher.

High T c Superconductors

W. Lc Johnson, E. Drescher-Krasicka* and Haydn N. G. Wadley

* Guest Scientist, Johns Hopkins University, Baltimore, MD

Two studies of high Tc superconductors are underway in the group. A study of

low- temperature ultrasonic elastic properties has been performed on the highTc superconductor YBa2 Cu3 07

_ x , with the aim of contributing fundamental data

on electron/lattice coupling. Changes in ultrasonic velocity normally

observed at the onset of conventional superconductivity are not apparent in

this material due to much larger anomalous changes between 40K and 220K

which, we discover, depend systematically on thermal history. These large

velocity effects, and an associated attenuation peak, are found to be

consistent with a first-order phase transition, perhaps magnetic in origin,

occurring below Tc

. Another DARPA project has been initiated to determine

the feasibility of using ultrasonic and eddy current measurements as in situ

sensors during processing of the high-Tc superconductor Bi-Sr-Ca-Cu-O. The

35
sensors are to be incorporated during heating and compaction of the ceramic

powder in a hot- isostatic pressing (HIP) chamber. The eddy current sensor is

currently being used in the HIP chamber and has the capability of monitoring

electrical conductivity, volume changing phase transitions and powder

densification with a resolution of one part in 10 A

. Initial tests of the

ultrasonic sensor indicate that reliable measurements of velocity can be made

up to 650° and be possibly up to 1000°C, enabling determination of phase

content and grain size/texture during sintering with or without the

assistance of pressure.

RSPD of Titanium Aluminides

W. L. Johnson, E. Drescher-Krasicka* , A. H. Kahn, and Haydn N. G. Wadley

* Guest Scientist, Johns Hopkins University, Baltimore, MD

This recently initiated DARPA/NRL funded project teams NIST with General

Electric (Aircraft Engines Division) and Drexel University to explore

innovative control concepts for the Rapid Solidification Plasma Deposition of

Intermetallic Composites. Work at NIST is directed at exploring potential

methods for characterizing microstructure during the spray process. Both

ultrasonic and eddy current methods are being investigated. Phase content,

grain size and film thickness are the primary parameters of interest. An

ultrasonic study has been initiated on a series of binary Ti-Al alloys with

the purpose of determining velocity as a function of temperature in the a,

a2 , ft and 7 phases

Sensing and Process Modelling of Hot Isostatic Pressing

A. H. Kahn, R. J. Schaefer, R. Clough, W. L. Johnson, E. Drescher-Krasicka*,

M. F. Ashby**, Y. Geffen***, M. L. Mester****, and Haydn N. G. Wadley

* Guest Scientist, Johns Hopkins University, Baltimore, MD

** University of Cambridge, England

*** Nuclear Research Center, Israel **** Research Associate, The Aluminum Association, Inc.

Traditional control concepts for hot isostatic pressing are based upon

sensing and maintaining temperature and pressure on a predetermined path,

Figure 4. Trial and error is used to identify the "best" path. Recent

advances in modeling the HIPing process at the University of Cambridge are

being coupled with research on novel sensors for measuring density,

temperature gradients, microstructure coarsening and microcracking to explore

the feasibility of implementing an Intelligent Processing of Materials

control concept, Figure 4. The DARPA funded program teams NIST researchers

with the BDM Corporation, the University of Cambridge (England), and possibly

Lulea University (Sweden) to test the IPM concept on the consolidation of

intermetallic composites. A consortium of HIP utilizing organizations has

been formed and helps guide the research and hasten industrial exploitation

of emerging technologies.

36
The eddy current sensor used for measuring the electrical conductivity and

temperature of aluminum extrusions also has the capability of being used for

determining dimensions (and thus, density) during HIPing. This provides a basis for direct control of density itself rather than temperature and

pressure which are not always capable of uniquely defining density. Research

on titanium- aluminum alloy powders has necessitated construction of a new

coil system capable of surviving at temperatures and pressures above 1000°C.

The new coil system is wound on machined tubes of boron nitride; the wires

are of platinum and platinum- rhodium alloys. Figure 5 shows the boron

nitride based coils placed in the HIP furnace. The test sample consists of a

copper or titanium tube with copper or titanium alloy powders sealed within,

Figure 6. The system permits an in situ measurement of the cross-sectional

area of the test sample during the processing.

Using data acquired with the above system we have computed the density as a function of time during a series of HIP runs. The histories of a typical

densification runs on a copper powder sample is shown in Figure 7. The

temperature and pressure schedules are displayed with the densities. The

dependencies of rate of densification on temperature are clearly

demonstrated. Detectability of subtler effects such as thermal expansion and

contraction at the beginning and end of the process is possible when one

examines the diameters corresponding to the measured cross-sectional areas.

This densification measurement is being used to explore the validity of HIP

process models (University of Cambridge), Figure 8, and shape change models

(Lulea University) . The validated models are then being used in

collaboration with BDM Corp. for numerical simulation of the densif ication

process in order to determine the optimal change to a process path to achieve

the "goal state".

Other sensors for measuring microstructure coarsening (grain size)

,

temperature gradients (which control deleterious densification gradient

phenomena and residual stress) and residual stress induced microcracking are

being explored together with the development of appropriate models relating

these quantities to temperature, pressure and time.

Steel Sensors

F. A. Mauer, D. Pitchure, S. J. Norton, Y. Grinberg*, and

Haydn N. G. Wadley

* Guest Scientist, Atomic Energy Commission, Israel

This ongoing program is directed at satisfying steel industry needs for

internal temperature sensing during the continuous casting and subsequent

thermomechanical processing of steel. Previous work at NIST on solidified

material has demonstrated the viability of an ultrasonic approach. Workers

from Battelle's Pacific Northwest Laboratory and AISI members have

subsequently demonstrated the viability of making these measurements in a steel mill using EMAT technology. NIST research during the past year has

37
focused on extending the ultrasonic approach to solidifying bodies where

knowledge of internal temperature and the solid shell thickness during

continuous casting could allow faster casting rates and reduced incidence of

breakouts

A fully automated ultrasonic temperature sensor developed at NIST in

collaboration with scientists from the AISI was described in the annual

report for 1987 and results from a test on a six inch square block of AISI

304 stainless steel were reported. In any application of this device to

monitoring the continuous strand casting process the strand may still have a

liquid center when it passes through the sensor. For this reason attention

has been directed toward use of the NIST's ten-channel ultrasonic sensor for

detecting and measuring this liquid core. Controlling the solid shell

thickness while increasing the casting speed promises substantial improvement

in the productivity of steel processing.

Initially, for laboratory tests, aluminum rather than steel has been used to

simulate a steel strand in order to avoid the extreme temperatures associated

with molten steel. A plate one inch think is used to simulate a section of a

6x6 inch strand in the apparatus shown in Figure 9. There is a two inch hole

through the plate so that both the upper and lower chambers can be filled

with molten aluminum when the stopper rod is raised. Suitable choice of the

initial temperature of the plate and of the molten aluminum results in a

portion of the material remaining liquid. By adjusting the power to the

resistance heaters in the chamber walls, it is possible to control melting

and solidification of the core for as many cycles as desired.

Measurements are carried out using laser pulses to generate ultrasonic waves

on one side of the plate and an array of five piezoelectric sensors to

receive them on the opposite side. The remaining two sides of the plate are

similarly equipped so that time-of- flight data can be obtained on as many as

fifty intersecting paths through the midplane of the plate in an identical

fashion to the approach used for solid bodies in earlier work. (See Figure

10 for one set of ten ray paths used for some tests)

Because the heat flow, is greater on the two surfaces where the detecting

transducers are located, the liquid-solid interface is elliptical. In order

to reduce the number of measurements required and to simplify the analysis,

we use a least squares technique to define an elliptically- shaped boundary

with unknown center, major and minor axes. At least four measurements are

needed to obtain the four parameters that define the ellipse. Using ten

measurements, the best elliptical approximately to the boundary has been

derived by fitting an ellipse to the time-of-flight measurements in a leastsquares sense. The results for three different center temperatures are

plotted in Figure 10 which shows the ten ultrasonic paths as well as the

estimated outline of the liquid core. The results have been confirmed by

embedded thermocouples and sectioning the block to determine the maximum

extent of the liquid and by probing the interface with a ceramic rod during

the experiment.

38
INTELLIGENT PROCESSING OF MATERIALS

PROCESS STEP LINKAGE

Figure 1. Schematic diagram showing the linkage of process steps to

produce a component with powder metallurgy.

VELOCITY MEASUREMENTS OF MODE A2 SiC-AI

Experiment

Theory —

V = 18 653 m/sec f = 3 MHz

.Figure 2. Comparison of theory and experiment for the A2 mode in specimen

composed of a SiC rod in an aluminum matrix Al/SiC. The experimental

apparatus was a prototype for an Interface Scanning Acoustic Microscope (IASM).

39

Attenuation

in

dB/(mm

x

MHz)
Figure 3. Transmit-receive coil system installed in canister, ready to be

placed in an extrusion press for the measurement of temperature of aluminum products.

Control Strategies for Hot Isostatic Pressing

Conventional IPM

Control algorithm

maintains process on

predetermined T,P cycle.

Density and microstructure

are under open loop

control.

Sensing

p,VT,|us sensor data is coupled with process

models to assess state of

process. Control algorithm

is adjusted during the

process to reach optimized

goal state.

Figure 4. Conventional and Intelligent Processing of Materials strategies

for control of hot isostatic pressing.

Zn
Figure 5. View of the boron nitride coil forms placed in the pressure

furnace. The powders to be sintered are sealed in a metal tube and placed in

the center of the coil system.

Figure 6. A schematic diagram of the HIP density sensor and a sample used for

testing.

41
COPPER HIP CYCLE (BOB13)

Figure 7 . Relative density vs. time during HIP cycle #13. The temperature and

pressure schedules are shown above the density data. Every tenth point is

indicated with a marker.

Pressure (MPa)

1.0 10 100 1000

Normalized Pressure, P/Oy

Figure 8. A preliminary HIP map for equi-atomic TiAl determined using the

Ashby approach. The reference stress for power law creep (aref) has been adjusted to give a map that best matches experimental data.

42
Tubular

Figure 9. Apparatus for measuring ultrasonic time-of-f light through an

alumunum plate with molten core.

CENTER TEMPERATURE

68 1 OEC C

CENTER TEMPERATURE

676 DEC C

CENTER TEMPERATURE

665 OEG C

Figure 10. Computer reconstructions of the solid-liquid boundary at three

distinct center temperatures.

43
-
CORROSION Dale E. Hall

Corrosion is a principal cause of shortened service life of metallic

structures, and contributes to many catastrophic failures involving loss of

life and property. The cost of corrosion to the U.S. economy is estimated to

be close to $200 billion per year. The key factors in reducing these losses

are better utilization of existing knowledge, better understanding of

localized corrosion mechanisms which can lead to premature failures, and new

research directed toward technologically significant materials and

applications. The programs of the Corrosion Group address these areas.

In FY 88, programs were carried out in four main areas: (1) corrosion of

advanced materials; (2) fundamental studies of localized corrosion

mechanisms, stress corrosion cracking, and measurement methods; (3) corrosion

data compilation, dissemination, and evaluation; and (4) corrosion problems

in disposal of high level nuclear waste.

Research on the aqueous corrosion and stress corrosion cracking of advanced

materials this year included a new program on the corrosion of ductile nickel

aluminide and derivative alloys. These materials are being pursued for a number of low- and high- temperature applications, and are currently the focus

of a technology transfer effort by Oak Ridge National Laboratory. Our

corrosion research results have been shared with Oak Ridge and their

industrial partners in a technology transfer workshop attended by potential

producers, fabricators, and users of the alloys.

Progress was made in understanding the mechanisms of stress corrosion and

localized corrosion, by combining experimental results with modeling studies.

Studies of the mechanism of transgranular stress corrosion cracking in pure

copper point toward the importance of localized dissolution as a common

mechanism for stress corrosion cracking. Our understanding of pitting

corrosion was advanced with the development of a stochastic model that

qualitatively reproduces experimental current fluctuations associated with

the formation of pits.

The Corrosion Data Program, a joint activity between the National Association

of Corrosion Engineers and NIST, serves as a central source of reliable,

evaluated corrosion data. The first commercially available software from the

program has been enthusiastically received by users, and work is continuing

on both an evaluated corrosion data base and the development of expert

systems for use in materials selection and corrosion control.

Our assistance to the Nuclear Regulatory Commission includes both evaluation

of published information and assessment of the technical issues involved in

nuclear waste disposal. In addition, laboratory measurements have been made

to increase our understanding of the influence of the environmental

conditions in the repository, to determine the performance of candidate

materials, and to develop more sensitive methods for detecting cracks in

waste canister materials.

45
FY 88 Significant Accomplishments

o The NACE-NIST Corrosion Data Center initiated an industry- funded program

to develop knowledge-base expert systems which incorporate symbolic

representation of expert's experiences and logic in selection of materials

and corrosion control methods for storage and handling of hazardous

chemicals and downhole equipment for new oil and gas resource production.

These systems are expected to become increasingly important information

sources for corrosion scientists and engineers when dealing with critical

materials applications.

o The aqueous corrosion behavior of ductile nickel aluminide was found to be

controlled by nickel in a variety of environments. Stress corrosion

cracking behavior of the nickel aluminide and a chromium- containing

derivative alloy was shown to be consistent with a mechanism involving

embrittlement due to hydrogen absorption.

o An experimental study of stress corrosion cracking of copper indicated

that the formation of small pits in the oxide film, rather than fracture

of an intact oxide film, was responsible for crack propagation.

Comparison of the copper results with those of other face-centered

materials suggests a common mechanism of transgranular stress corrosion

cracking involving localized dissolution.

o An analysis of the fluctuation of electrical parameters, i.e. noise,

accompanying localized corrosion has shown that frequency spectra of the

noise can be used to determine the repassivation rate of metal surfaces.

Computer simulations were used to show that the technique can provide

useful results even wherr-large- numbers of difficult- to-resolve

fluctuations are produced.

o Corrosion Group expertise in test methods for evaluating localized

corrosion phenomena is being used to provide critical data for

interpretation and evaluation of DOE-sponsored studies on corrosion of

nuclear waste packaging materials. Key issues studied in the experimental

program include the effects of projected repository conditions on

corrosion behavior of carbon steel, pitting and stress corrosion cracking

(SCC) of other corrosion resistant materials, and detection of SCC

propagation.

Corrosion of Advanced Materials

D. E. Hall, R. E. Ricker, U; Bertocci, J. L. Fink

Corrosion of Intermetallic Compounds - Nickel aluminide is a new engineering

material with a broad range of both high- and low- temperature potential

applications, including jet engine parts, metal matrix composites, dies, and

drill bits. The Corrosion Group work on nickel aluminide alloys is aimed at

providing useful corrosion data and an understanding of the mechanisms

underlying aqueous corrosion and stress corrosion cracking (SCC) behavior of

the alloys.

46
Materials studied include the basic ductile alloy, IC-50, which contains a small amount of boron to provide ductility, and a chromium-containing

version, IC-218, with superior high temperature oxidation resistance. Both

cold-worked and annealed samples of each alloy were studied. The alloy

specimens were supplied by Oak Ridge National Laboratory. For comparison,

experiments were also performed on the parent metals, pure nickel and

aluminum. The test environments were selected to provide a variety of

corrosion behaviors: one parent metal (Ni) stable (0.5M NaOH) ; both parent

metals passive without pitting (0.5M Na2 S04 ) ; both passive with pitting (0.5M

NaCl) ; and, both parent metals unstable with the possibility of hydrogen

effects (0.5M H2 S04 ). Slow strain rate experiments were conducted in the

electrolytes and in air as reference, using a strain rate of 10" 6 /sec.

The open circuit potential behavior of the IC-50 alloy was dominated by

nickel in all electrolytes (Figure 1). Alloy and nickel potentials were not

greatly affected by pH changes. Cyclic voltammetry, used to study the

polarization behavior, indicated that the electrochemistry of nickel

aluminide and nickel were essentially similar in all the electrolytes

studied. Nickel dissolution was evident in acidic electrolyte. In neutral

chloride, the current corresponding to pitting of Al was absent from the

alloy voltammogram , and the alloy began to pit at about the same potential as

nickel. In alkaline electrolyte (Figure 2), the peaks corresponding to the

oxidation and reduction of nickel surface species were observed on both Ni

and the alloy. The aqueous corrosion results indicate that, under a wide

range of conditions, the known corrosion behavior of nickel is useful for

predicting the behavior of nickel aluminide.

Slow strain rate experiments showed that both cold-worked and annealed IC-50

alloy experienced no stress corrosion cracking in the neutral and alkaline

electrolytes. Loss of ultimate tensile strength was pronounced in acidic

electrolyte, particularly with the annealed alloy. IC-218 alloy behaved

similarly to IC-50. -Fractography showed clearly that both the annealed and

cold-worked alloy fractured transgranularly in a ductile manner in air.

Similarly, failure was ductile in all electrolytes except acids, where

failure was brittle and intergranular for both the annealed and cold-worked

alloy.

The SCC behavior in acid indicated that a mechanism involving hydrogen

embrittlement occurs at open circuit. In support for this mechanism, a plot

of free corrosion potentials for the alloy in the environments studied showed

that hydrogen generation is thermodynamically possible in acid but not in the

other electrolytes.

Stress Corrosion Cracking of Aluminum- Lithium Alloys - Aluminum- Lithium

alloys, combining higher strength and modulus of elasticity with lower

density, are being evaluated for critical aerospace applications.

Maintaining good fracture toughness and corrosion resistance in required

product forms is a prerequisite for acceptance. Corrosion Group studies, in

cooperation with Alcoa, are evaluating the role of grain boundary

microstructure on stress corrosion cracking resistance of these alloys.

High purity Al-Li binary and Al-Li-Cu ternary alloys were given different

heat treatments that resulted in different grain boundary structures but give

47
the same yield strengths (matrix precipitate size distribution) . In contrast

to normal aging heat treatments which result in different grain boundary

structures and different yield strengths, this technique allows the

evaluation of the influence of grain boundary microstructure on the stress

corrosion susceptibility of these alloys without the confusion that results

from simultaneously altering the yield strength. The results indicate that

the grain boundary precipitates strongly influence the susceptibility of

these alloys to stress corrosion cracking and that it may be possible to

achieve maximum resistance to stress corrosion cracking at peak strength by

adjusting heat treatment to control grain boundary microstructure.

Surgical Implant Metals

A. C. Fraker and J. S. Harris

The metals which are used in the human body as surgical implants for

orthopedic, dental, heart pacemaker and other purposes include 316L stainless

steel, a Co-Cr-Mo alloy, a Co-Ni-Cr alloy, a Ti-6Al-4V alloy and unalloyed

titanium. The corrosion behavior and mechanical properties of the device are

dependent on metallurgical aspects of the design and production. Corrosion

behavior is important since metal ion release into the body should be avoided

or kept at a low level. The device should not fail due to corrosion or to a combination of corrosion and mechanical property deterioration.

Repassivation Studies - Repassivation kinetics of surgical implant metal in

simulated body fluids influence metal ion release into the body and also

mechanical strength, which may involve surface film repair. Electrochemical

data have been collected for determining repassivation rates and surface film

stability. This involved exposing a clean metal surface to simulated body

fluid at a preselected potential and measuring the current decay versus time

at temperatures of 22°C, 37°C and 50°C.

Surface Films on Titanium and Ti-6Al-4V - Information on surface preparation

was provided to various dental implant manufacturers. The success of dental

implants had increased dramatically in recent years and now some dental

surgeons report 85 to 95 percent of implants last for periods of 5 to 10

years. The materials used for most dental implants are titanium and Ti-6Al4V. Dental surgeons receive the titanium implants in various conditions,

including passivated, acid washed, grit blasted, porous coated, sterilized by

various methods, etc. The chemical and metallurgical condition of the

surface will vary with all of these treatments. The nature of the metal

surface will influence reactions and forces of the tissue/substrate interface

which determine whether the bone growth and firm attachment occur.

Electrochemical procedures for determining surface condition were described

and demonstrated to the Artech Corporation, Falls Church, VA. This involved

mounting the implant and measuring the open circuit electrode potential of

the implant in a simulated body fluid. Such measurements can demonstrate

whether the implant has been passivated, cleaned with an alkaline solution or

exposed to other treatments. Oxide films on titanium materials progress

through a series of Ti/0 ratios to the highest oxide, Ti02

. The Ti oxide,

and thus the electrode potential is dependent on chemical surface treatment,

temperature, the environment, etc. Measured rest potentials in body fluids

indicate that the Ti surface is an intermediate oxidation state. Determining

48
the optimum surface condition may be an important factor for increasing the

dental implant success rate.

The effects of different heat treatments and small differences in composition

on the mechanical properties of Ti-6Al-4V alloy were studied by comparison of

the British and the U. S. extra low interstitial (ELI) grades of Ti-6Al-4V.

Transmission electron microscopic structural analyses were conducted at NIST

and were correlated with mechanical property measurements made by Catherine

Asgian at Zimmer, USA of Warsaw, Indiana. These results indicated some

similarities and some differences in the materials but showed there was no

advantage in changing the American Society for Testing and Materials (ASTM) F

136 Specification for Ti-6Al-4V to include a higher oxygen content.

Corrosion Mechanisms and Measurement Methods

T. Cassagne, E. Pugh, R. Ricker, M. Stoudt, and J. Fink

Mechanisms of Stress Corrosion Cracking - Investigations of the mechanisms of

transgranular stress corrosion cracking (T-SCC) of pure copper and brass have

been carried out with emphasis on the film- induced cleavage model. According

to this model, crack propagation occurs by discontinuous cleavage, each

brittle event being initiated in a thin film formed at the crack tip by

interaction with the environment. Dealloyed layers and oxide films have been

suggested as a possible starting points for the cleavage event, but in the

case of Cu, which is known to undergo T-SCC, selective dissolution as well, as

hydrogen embrittlement can be eliminated as possible causes. Thus the study

focuses on the role of oxide films, which, in the first part of this work,

were shown to be a prerequisite for the occurrence of T-SCC.

Experimentally, T-SCC of copper has been studied by conducting slow strain

rate tests on single crystal specimens in aqueous sodium nitrite and sodium

acetate. The tests were conducted at different pH values, electrode

potentials and strain rates. Oxide formation was investigated by means of

potentiostatic and potentiodynamic techniques on (110) single crystal faces,

the reported fracture plane, in conjunction with ellipsometry and electron

microscopy

The oxide growth process was investigated in two solutions which induce T-SCC

in copper, namely 0.1 M sodium acetate, pH 5.5 and 1 M sodium nitrite, pH 9

Initially a thin cuprous oxide film (10 A or less) was found to form in both

solutions. Subsequently, this film breaks down at multiple sites by pitting,

and this is followed by the formation of a thick porous cuprous oxide

(several hundred A) by dissolution and precipitation.

In terms of the model, the thin oxide was expected to be the film nucleating

cleavage. However, the results indicate that the formation of very small

pits in the oxide film is responsible for crack propagation and not fracture

of an intact oxide film as was originally suggested. Comparison of the

behavior of copper with that of other face-centered-cubic materials suggests

that a common mechanism of T-SCC involving localized dissolution is

operative

Experiments have been initiated to see if SCC of brass can be observed in

chloride solutions. Because of aqueous complex formation, a significant part

49
of the electrochemical behavior is similar to that in ammonia solutions,

where SCC is known to occur. Extensive dezincification is observed in the

presence of oxidants, much less in solutions in equilibrium with respect to

copper. Slow, constant strain rate fracture tests have so far failed to show

T-SCC, however. Further studies at higher strain rates are planned.

Corrosion Measurement Methods - Fluctuations in the electrical parameters of

electrodes undergoing localized corrosion contain information useful in

understanding the nature of the corrosion process. Examples are the rapid

current spikes often detected during the induction period preceding the

formation of stable pits, such as those shown in Fig. 3a. The analysis of

such fluctuations has been carried out by considering them as a form of shot

noise. They have been analyzed both in the frequency- and in the timedomain. From the frequency spectra, such as those shown in Fig. 3b, the rate

of repassivation can be obtained from the position of the "knee" in the

spectrum. Comparison of the spectra of pure Fe and Fe-Cr alloys shows that

repassivation in chromium steels is about one order of magnitude faster than

in iron, as would be expected because of the greater corrosion resistance of

the Cr-containing alloys.

Computer simulations have shown that the treatment is valid even when,

because of the high number of spikes, they cannot be easily distinguished;

this is the case in the simulation run illustrated in Fig. 4a. The frequency

spectrum (Fig. 4b) is similar to those derived from the experimental data,

and from it both the process intensity and its decay rate can be obtained.

Corrosion Data Center

D. B. Anderson, C. D. Flanigan, P. Karras*, C. P. Sturrock** , and K. A.

Lichti

* NACE Research Associate

** MTI-NACE Research Associate

*** Research Associate sponsored by the New Zealand Department of

Scientific and Industrial Research and NACE

The Corrosion Data Center is a joint program between NIST and the National

Association of Corrosion Engineers. The Center serves as a focal point for

the development of personal computer programs to facilitate widespread

distribution of evaluated corrosion performance and control data for

engineering materials exposed to a wide range of industrial environments

.

Activities in 1988 centered on:

(1) Completion of the Cor- SurTM corrosion data survey software, which

provides isocorrosion charts for a variety of metallic and

nonmetallic materials in over 1000 chemical environments. These

programs have received strong industry acceptance, with over 600

copies sold to date.

(2) Leadership role in development of consensus corrosion data format

standards through ASTM and NACE.

(3) Development of a prototype corrosion database structure and data

entry from a large industrial corrosion data source. Arrangements

have been completed to access additional data sources for inclusion

50
in this comprehensive program, which is designed to accommodate

corrosion data from multiple sources in a standardized format.

(4) Initiation of two new industry sponsored projects which introduce the

concepts of knowledge-base information processing to capture

interpretive concepts of proven expertise. These expert system

programs are expected to be milestones in our goal of developing

innovative methods for distribution of corrosion information to a broad user audience.

The initial industry contract with the Materials Technology Institute

of the Chemical and Process Industries (MTI) has helped establish the Data

Center as a focal point for addressing the complex issues in gathering and

disseminating evaluated corrosion data with an industry consensus on the

relevance and applicability of the data. Additional contracts are currently

under negotiation.

Corrosion Issues in Nuclear Waste Containment

C. G. Interrante, D. Anderson, U. Bertocci, E. Escalante, A. Fraker, D. Hall,

J. Harris, S. Harrison, W. Liggett, E. Plante, E. N, Pugh, R. Ricker, J.

Ruspi, M. Stoudt

Nuclear Waste Packaging Materials - In a program titled "Evaluation and

Compilation of DOE Waste Package Test Data," initiated in FY85, NIST

supports the High Level Waste (HLW) Management Program of the Nuclear

Regulatory Commission (NRC) by evaluating the Department of Energy's

activities on high level waste disposal. The waste packages, radioactive

waste from nuclear power plants and other sources, are being designed for

storage in a permanent repository. Potential problems threatening waste

package integrity including pitting, stress corrosion cracking, and hydrogen

embrittlement, are the focus of the Metallurgy Division's efforts. Another

area of concern, leaching of borosilicate glass, is investigated with the

assistance of consultants and NIST personnel outside the division. The

program is supported by statistical and modeling specialists from the Center

for Computing and Applied Mathematics, as well as by consultants from outside

NIST. The HLW Data Center established at NIST includes over 986 papers and

technical reports. A computerized data base provides access to these

materials. The data base also includes the full texts of all technical

reviews of published work.

The technical assistance rendered to the NRC includes formal reviews of the

research and development efforts of the DOE Waste Package Program. Over 38

reviews were completed in FY88. Technical review of other related documents

(from NRC, DOE and their contractors), interaction with the international

technical community, and general review of all relevant present and planned

activities of the DOE are also important elements of the program. Subjects

considered in the review of published studies include expected modes of

degradation, evaluation of various other failure modes, test methods, design

of experiments, theoretical and modeling efforts, and laboratory testing. An

important objective is to identify additional data and types of tests needed

to demonstrate that the DOE waste package designs will meet NRC's performance

obj ectives

51
The materials research program provides data to aid in the interpretation and

evaluation of data submitted by the Department of Energy (DOE) to the NRC for

licensing the repository, materials and procedures for nuclear waste

disposal. During this past year, DOE selected Yucca Mountain, Nevada as the

first planned site for underground storage of nuclear waste. This site

consists of tuff (crystallized volcanic rock) which has approximately twelve

percent porosity. The rock contains very little water (2 to 3 mm flow/year)

and oxygen is present. The selection of this site from among three candidate

sites will sharpen the focus of future research. This year laboratory

studies were carried out in four areas: (1) Effects of Transport and

Resistivity on Corrosion of Waste Package Materials, (2) Pitting Corrosion of

Steel Used for Nuclear Waste Storage, (3) Corrosion Behavior of Zircaloy

Nuclear Fuel Cladding, and (4) Evaluation of Methods for Detection of Stress

Corrosion Crack Propagation in Fracture Mechanics

Effects of Transport and Resistivity on Corrosion - Studies sponsored by DOE

indicate that if the metals considered for nuclear waste containers corrode

uniformly, their lifetimes will be thousands of years. If nonuniform

corrosion such as pitting occurs, however, the lifetime of the containers

will be reduced to a few hundred years, not enough time for the nuclear waste

to lose its nuclear toxicity. This study is considering the effect of

transport and resistivity properties of the environment on the form of

corrosion that occurs on steel.

Small steel coupons were immersed in a matrix of environmental conditions in

which transport and resistivity were controlled. Electrochemical

measurements, which include corrosion rate measurements and measurements of

oxygen transport through med.ia_ simulating underground conditions, indicated

that in a wet sand environment where transport of oxygen is relatively low,

corrosion rate is also low, and in a sand-free solution with high oxygen

transport, corrosion rate is high compared to the sand environment. In

addition, a high conductivity environment results in a higher rate of

corrosion for steel compared to lower conductivity environments. The results

indicate that oxygen transport and electrical conductivity in the repository

environment may have significant effects on corrosion of waste containers,

and are important properties to consider in characterizing the repository

environment

.

Pitting Corrosion of Steel Used for Nuclear Waste Storage - Steels, such as

AISI 1040, and ASTM A-27, grade 60-30, and others in the low to intermediate

carbon range have been considered for use as nuclear waste canister materials

or as borehole liners. Stainless steels, such as 304 and 316, also have been

considered for use as canister materials. This project deals with localized

corrosion behavior of steel with emphasis on A27 steel. Electrochemical

measurements were made to determine susceptibility to pitting in a high pH

(9.75) electrolyte containing various ions which could be present in

repository environments. Cyclic polarization measurements of A27 steel at

22°C and 95°C, as described in ASTM G61, showed that the pitting potential

was slightly positive to the corrosion potential and that pitting probably

would occur on a large scale. Microstructural analysis showed the presence

of shallow pits and preferentially corroded pearlitic regions. Corrosion

52
rates for A27 under these test conditions were 6 rails per year (mpy) at 22°C

and 12 mpy at 95 °C.

Corrosion Behavior of Zircalov Nuclear Fuel Cladding - Approximately ninety

percent of the nuclear waste to be stored will be in the form of nuclear fuel

with a Zircaloy cladding. This project deals with studies of surface

oxidation, passivity, and susceptibility to localized corrosion such as

pitting or stress corrosion cracking (SCC) of the material. Zircaloy

materials were obtained from Teledyne Wah Chang and cladding was obtained

from the General Electric Co. and Babcock and Wilcox. An extensive

literature review was conducted on the corrosion of Zircaloy, and an analysis

of the published data was prepared and submitted to the NRC . Electrochemical

tests in high pH aqueous media at 95°C indicate potential pitting problems,

and further studies are being conducted.

Evaluation of Methods for Detection of Stress Corrosion Crack Propagation in

Fracture Mechanics Specimens - The purpose of this project is to detect crack

extension or crack initiation activity, resulting from stress at flaws or

material discontinuities, which occur after long times of up to 4.5 years.

This project is directed toward early detection and toward developing

procedures for accelerated testing. An acoustic emmission technique is used

for these measurements. The success of this technique would result in the

capability to measure crack growth at a sensitivity which has not been

possible previously and would improve predictions of stress corrosion

cracking suceptibility and failure. Instrumentation and software were

developed for these tests. Tests were conducted on 2.25 Cr - 1 Mo steel in

deaerated acetic acid solution saturated with hydrogen sulfide. Some aspects

of the test apparatus are being changed to keep the environment oxygen free.

After the test method is developed, other environments and materials will be

studied.

53
Figure 1. The open circuit (free corrosion) potentials of cold worked and

annealed nickel aiuminide are dominated by nickel in acidic,

neutral, and alkaline electrolytes.

CME

o

<

E

3?

w

c

02 Q

c

02

i_3

o

10 o -1.0 -2.0

Potential, VSCE

Figure 2. In oxygen- containing 0 . 5M NaCl electrolyte, an anodic current

associated with pitting begins to flow at about OV/SCE on both

Ni and Ni 3 Al. The alloy does not show current corresponding to

pitting of Al

.

54
AMPLITUDE.

A B

Figure 3. Current fluctuations recorded before pit initiation on various

materials. A) Part of time record, taken on pure Fe in borate

buffer + NaCl. B) Power spectra.

>

£XPCN. 4096 PTS. 64 AVER. TAU- 16.0. RATE- C. 05 a/p t. P- C. 25. 4 SMOOTH. Loq (SPO) 1 i ra —1.20

{

i 1 — 1 :

1

TIME, s

EXPON. 4096 PTS. 34 AVER. TAU- 16.0. RATE” 0.05 «/pt. P- 0.25. 4 SMOOTH. Log (SPO) 1 1 «—1.20

A B

Figure 4. Computer

A) Part

ensemble

mode 1

s imulation

of the time

averaging

of random transients. Exponential decay,

record. B) PSD of the transients after

Dashed curve is spectrum calculated from

55

am
-
ELECTRODEPOSITION David S . Lashmore

The Electrodeposition Group is responsible for measurements and standards

associated with electrodeposited metals and alloys. The objectives of the

group are: (1) the determination of the critical mechanistic, materials, and

process variables controlling the structure/property relationships of

electrodeposited coatings and the development of approaches that will result

in entirely new materials; (2) the provision of standards such as coatings

thickness standards, dye penetran crack standards, and tin- lead alloy

standards; (3) the development of new standards requiring electrodeposition

for their fabrication or utilizing the unique properties of electrodeposited

alloys; (4) the provision of government expertise to industry, through

research associates and standards organizations, and to the government

agencies, through appropriate contracts and consulting arrangements.

Following are some of the many areas in which coatings are important to the

commerce of the United States: (1) Strategic Materials - it has been shown

that appropriate alloy coatings can provide a 30% savings of imported raw

chromium. Research on new alloys in progress indicated that for many

applications, coatings can replace bulk stainless steels. (2) Corrosionelectrodeposited coatings play an important role in corrosion protection. It

has been estimated that the cost of corrosion to the U.S. economy is in

excess of 200 billion dollars per year. (3) Wear - The cost of wear to the

U. S. economy has been estimated at about 50 billion dollars per year.

Electrodeposited coatings play an important role in improving wear properties

and surface coatings can be optimized for particular wear situations. (4)

Electrodeposition Industry - specifically plays an essential role in the

United States economy. For example, almost 900K tons of electrogalvanized

sheet and strip are produced annually with an estimated impact of about $150M

per year projected by 1990, approximately 550K tons of metal coated wire and

wire products are produced per year, tin plate accounts for 8800 tons with a dollar impact of $120M, and foil production accounts for about $200M per

year. (5) Magnetic Materials - Most hard disk drives are produced utilizing

electrodeposition technology which thus has an important impact on the United

States computer industry. (6) Processes - including decorative coatings,

electroforming (compact discs), and electronic application (contacts, PC

boards etc.) are so important that without electrodeposited coatings much of

our current industry would not be able to function in its present form. (7)

Advanced Alloys - new approaches using electrochemical deposition have

resulted in new materials whose properties can be tailored on a near atomic

scale. Basic work is now going on in electroformed intermetallics , advanced

composites, and new magnetic materials.

FY 88 Significant Accomplishments

o Production of Coating Thickness Standards was increased by 15% over

previous years to 7,000 standards. This was accomplished in part by

converting to a microcomputer controlled measuring system.

o Developed three new coating thickness standards as requested by the

American Welding Institute. These coating thickness standards provide

standardization values for designating the delta ferrite content of
austenitic stainless steel weld metal formed when the weld metal

solidifies

.

o Abrasive wear rate was reduced by 50% by incorporating B 4 C (tetra boron

carbide) into a chromium matrix, compared with hard chromium. An

alternate system showing promising results is a particulate composite

alloy using a nickel matrix in which SiC is incorporated. Preliminary

tests show a reduction in wear of 44% compared with hard chrome. (note

that hexavalent chromium is highly toxic)

o Problems of interfacial diffusion in metal matrix composites are being

addressed by electrodeposition of diffusion barriers in a joint program

between the National Institute of Standards and Technology (NIST) and

American Cyanamid Corporation. Barriers for carbon/nickel

interdiffusion have been electrochemically produced on graphite fibers.

Alloys of cobalt with tungsten have shown significant benefit in

suppressing interdiffusion.

o The mathematical model of alloy deposition onto moving filaments

considering potential distribution in solution and within the working

electrode, has been expanded to include the concentration polarization.

A bench top cell has been completed and successfully operated.

o Recent developments in the Electrodeposition Group on modulating the

microstructure of chromium are expected to lead to significant advances

in wear performance for many applications. Microlayered chromium has

been found to have apparent anisotropic deformation which depends on

layer spacing. Microhardness of microlayered chromium was found to be

1500-1800 KHN/25gf at layer spacings of 1 to 3 nm.

o The composition and structure of aluminum alloys electrodeposited from

chloroaluminate electrolytes can be rigorously controlled by melt

composition, temperature (120-500 °C)

,

and electrode potential. In the

Al-Mn system, the direct deposition of amorphous, metastable

(icosahedral and decagonal), and crystalline (Al 6 Mn + unknown) phases

has been demonstrated. This is the first evidence for the direct

electrodeposition of aluminum intermetallic compounds.

o Al-Ti alloys containing up to 40 wt % Ti have been electrodeposited from

chloroaluminate electrolytes at 150 °C. Heat treatment converts the

deposit to a mixture of Al and Al3 Ti as predicted by the equilibrium

phase diagram. The direct deposition of AlTi and Ti 3 Al should be

possible from this electrolyte at elevated temperatures. Forming

intermetallic compounds by electrodeposition may overcome fabrication

and machining problems inherent to the material and which presently

limit other processing techniques.

o Tin/Lead SRMs certified for specific assigned mass per unit area and

specific composition are being developed for sale by the Office of

Standard Reference Materials. This alloy (60Sn-40Pb) is in wide use by

the electronics industry and the production of SnPb SRM's has been

requested by the American Society of Testing and Materials.

58
o Significant improvements in production techniques for electrochemically

producing artificial superiattices have been made. The new technology

allows compensation for random disturbances in the electrolyte and has

yielded samples significantly better than those produced by other

processing technologies. Magnetic studies of these new atomically

controlled superiattices have yielded new data on the temperature

dependence of the saturation magnetization, have proven the absence of a magnetic dead layer at the interface, and are expected to provide other

new insight into metal physics.

Metal Matrix Composites

C. R. Beauchamp, S. A. Claggett, C. E. Johnson, D. R. Kelley, D. S. Lashmore

J. L. Mullen, P. N. Sharpless, G. R. Stafford, and N. S. Wheeler

Electroforming Metal Matrix Composite Precursors - A two year investigation

of interface behavior in metal-matrix composites has been initiated in cooperation with the American Cyanamid Corporation and in collaboration with

members of the Metallurgy Division and the Center for Analytical Chemistry.

A literature study revealed that much of the research on metal -matrix

composite interfaces has been done by the Soviets, and many of the Russian

papers have been translated (K. W. Pratt). The focus of this year's research

has been the stabilization of the interface between nickel and graphite so

that deterioration of the mechanical properties of graphite might be reduced

or eliminated at elevated temperatures. The problem is the interdiffusion of

nickel and carbon at high temperatures (i.e., greater than 600 °C)which

results in a brittleness and decrease in diameter of the fiber. The research

effort has focused on the electrodeposition of an alloy containing a carbideforming element directly on the graphite fiber prior to the outer nickel

layer. Of the alloys considered, Co-W has been successfully electrodeposited

from aqueous solution onto graphite fibers of polyacrylonitrile (PAN) base.

Scanning Electron Microscopy (SEM) (A. J. Shapiro) has indicated that for the

Co-W coated fibers in a nickel matrix: 1) no change in shape or measurable

decrease in the size of the fibers occurs as a result of annealing at 800 °C

for 24 hours, and 2) nickel diffused through the Co-W layer but had not

penetrated the fiber (see figure 1). This dramatic improvement in the

tolerance of the graphite fibers for nickel is apparently due to a very thin

layer of an unidentified species or combination of species. A Transmission

Electron Microscopy/Electron Diffraction (TEM/ED) study has just been

initiated to characterize the interface, preliminary X-ray diffraction

studies of annealed Co-W coated fibers have shown Co 3 W3 C and Co 6 W6 C to be

present. A comparison will be made between the phases found by TEM/ED and

those predicted by the quaternary phase diagram for C-Co-Ni-W. Mechanical

property studies by fiber punch-out and tensile testing are also underway.

Mathematical Modeling - The efforts in this past year have been concentrated

on the completion of the mathematical modeling of the deposition process onto

moving wire. Previous assumptions with respect to the linear dependence of

the resistivity of the alloy have been eliminated and the correct dependence

based on experimental data has been included in the form of a fitted

polynomial over published values for this property. In addition, the finite

difference algorithm used to solve the partial differential equations has

been upgraded to include a treatment of unequal intervals during the

59
determination of the grid spacing. This allows a greater resolution on

regions of higher gradients for the parameter under consideration and a

greater stability during the convergence of the method. The two most

important parameters while solving the coupled differential equations are the

concentration of the active species and the potential distribution in

solution. Considerable effort has been given to the choosing of the proper

transformation function while solving for these parameters. Unfortunately

the same transformation for the radial distance is not suitable for the whole

treatment because the potential distributions behave logarithmically in the

neighborhood of the electrode surface while the concentration profile behaves

logarithmic at the surface, but decays to the negative power of one third at

the jet exit. The best transformations found for the potential and

concentration profiles are represented in figure 2.

Deposition of the Aluminum Alloys - the Matrix - Aluminum alloys can be

electrodeposited from molten salt electrolytes containing A1C13 , NaCl and the

chloride salt of the solute metal at temperatures as low as 110 °C. For

example, the addition of small quantities of MnCl2 to the chloroaluminate

melt results in the deposition of a wide variety of binary aluminum -manganese

alloys. The electrodeposition of these alloys from molten salt electrolytes

offers many advantages over conventional solidification techniques. Not only

can one rigorously control the alloy composition (through melt composition

and electrode potential) , but the span of operating temperatures possible

(120-500 °C) allows for the deposition of a variety of structures. By

altering the temperature of the electrolyte during deposition, one can

electrodeposit homogeneous films of amorphous, metastable, and equilibrium

phases. The ability to electrodeposit thick, uniform films of the

icosahedral and decagonal phases for instance, may lead to the first

mechanical property measurements of these very important materials.

Similarly, Al-Ti alloys can be electrodeposited from chloroaluminate

electrolyte containing Ti+2

. The deposition potential of titanium is very

close to that of aluminum; consequently, a broad range of alloy compositions

is possible as long as the concentration of Ti+2 is sufficient to support the

partial current required for titanium deposition. Presently, the

electrolytes contain about 40 mM Ti+2

. Electrodeposition from this

electrolyte at 150 °C and at moderate current densities (1-20 mA/cm2

) results

in alloys containing 10 -20 wt.% Ti which convert to a mixture of Al and

Al3 Ti upon heat treating at 600 °C. At very low current densities (100

/iA/cm2

) , the titanium current efficiency increases significantly and we have

observed structural evidence (x-ray diffraction) for the direct

electrodeposition of AlTi. Forming intermetallic compounds by

electrodeposition, particularly the titanium-aluminides , may help overcome

fabrication and machining problems inherent to the material and presently

limiting other processing techniques.

Direct Adhesion Testing of Cobalt-Tungsten Alloys on Fibers - Techniques were

developed to measure adhesion of coatings to fibers as small as 7/zm. The

technique incorporates a dynamic microhardness instrument (U. S. Patent

4,699,000) using a custom made diamond indentor. These methods revealed that

alloys of Co-W adhere significantly better to silicon carbide than copper or

nickel. Tests are currently underway on graphite and on other coating

60
alloys

Composition Modulated Deposits for Application as Neutron Mirrors

D. S. Lashmore , C. E. Johnson, and U. Bertocci

Research on electrodeposited composition modulated coatings for possible

application as neutron mirrors resulted in the development of an electrolyte

to produce nickel -manganese and nickel-tin microlayered deposits.

Galvanostatic pulse plating techniques were developed to deposit discreet

alternating layers of nickel/nickel -manganese and nickel/nickel- tin from the

single electrolyte. A scanning electron micrograph of a representative

nickel/nickel-manganese layered deposit is shown in figure 3 with the

associated energy dispersive x-ray analysis of the composition of the coating

cross-section.

Wear Resistant Coatings for the Printing Industry

C. E. Johnson, D. R. Kelley, J. L. Mullen, and D. S. Lashmore

A one year study of the wear of electrodeposited coatings on wiper blades

used on water-wipe currency printing presses at the Bureau of Engraving and

Printing was completed. The purpose of the study was twofold, to extend the

life of the wiper blades beyond that obtained with unplated steel blades and

to compare the results of laboratory accelerated wear testing with in- situ

wear testing of coated blades on the printing presses. Four types of

chromium coatings (BEP hard chromium, milky non-cracked chromium, direct

current deposited duplex, and pulse plated duplex) were deposited on W-l

wiper blades and evaluated for wear performance. The coatings were obtained

by direct current (DC) plating, galvanostatic pulse plating, and by varying

operating parameter, such as temperature and current density. The laboratory

and in- situ wear tests results'" of the four types of chromium coatings are

compared in figure 4. It was found that coating W-l blades with 100 fim of

BEP hard chromium, the life of the blades could be extended 10-15 times the

life of the uncoated blades. The laboratory accelerated wear tests of the

pulse plated duplex chromium coatings show a 50% improvement in wear

performance over the BEP hard chromium; whereas, the in-situ wear tests show

a 30% improvement. The trends indicated by the in-situ testing provided a

good check of the laboratory testing.

Three wiper blades (W-l, W-2, and W-3) are incorporated in each water-wipe

press. The wear environment of the three blades range from wet abrasive to

dry abrasive. The wet abrasive environment has been investigated with the

coatings on W-l blades. W-3 blades are subjected to the dry abrasive

environment. In-situ wear results of hard chromium coated W-3 blades

indicated that the life was extended 4-6 times over the unplated blades, but

this was only one-half the life extension noted for W-l blades. This result

is indicative of the severity of the dry abrasive environment. Another type

of coating, particulate composites, were investigated for wear performance in

the laboratory to address the severity of the dry abrasive environment of the

W-3 blades. The composites were either a nickel or chromium matrix with

silicon carbide or boron carbide particles. A summary of the wear rates of

the composites are compared to the steel and hard chromium coated blade

sections in figure 5. Composites of 5 /im boron carbide particles in either

61
the nickel or chromium matrix wore up to 2.5 times better than the hard

chromium.

An extension of the work on pulse plated duplex chromium deposits has led to

an investigation into the deposition of structure modulated (SM) chromium

coatings. Modulated deposits were prepared with layer spacings from 1-500

run. X-ray diffraction of these deposits have indicated that different

structures (BCC, HCP, and FCC) can be obtained but maintaining these as

stable structures has not been achieved except for the normal BCC structure.

The layers that have been induced, figure 6, appear to be caused by texturing

(preferred orientation) of which control has been achieved by controlling the

pulsing parameters, current density, and electrolyte temperature.

Microhardness testing of these deposits resulted in hardness values of 1500-

1800 knoop hardness numbers when measured at loads of 0.098 newtons (10 gf)

and 0.245 newtons (25 gf ) . These hardness values compare to 1000 knoop

numbers for hard chromium.

Standard Reference Materials

H. J. Brown, H. G. Brown, D. R. Kelley, D. S. Lashmore , and P. N." Sharpless

This year, the Electrodeposition SRM production staff certified over 7,000

coating thickness standards, a 15% increase over FY87. Included in this

years production, were three new coating thickness standards which were

requested by the American Welding Institute and were completed six months

ahead of schedule

.

The increase in production can be attributed to the conversion of the S-100

computer system to the new micro computers, and modified programs.

Research on the Standard Reference Material, Sn-Pb is rapidly concluding and

production is slated to begin by November 1, of this year. These standards

will be certified for composition and thickness (specific mass per unit

area)

.

Work is in progress on a new standard reference material, Ni-P. This

standard will be certified for thickness (specific mass per unit area and

phosphorous content. A second x-ray florescence unit has been purchased

which will be dedicated solely to detecting light elements, and will be used

to certify the Ni-P standard for thickness and phosphorous content.

Planning has begun to redesign the award winning, Scanning Electron

Microscope Certification Standard. It is proposed to change from the present

Ni-Au layered structure to possibly a Ni-Gu or Ni-Ag system. The

Electrodeposition Group will contract to develop this new plating system

only. Certification of the standard will be done elsewhere at NIST.

Electrochemical Deposition of Artificial Superlattices

D. S. Lashmore, R. R. Oberle, S. A. Claggett

Significant progress has been made in the deposition and characterization of

Copper-Nickel composition modulated alloys under sponsorship of the IBM

Corporation. A refinement of a potentiostatic deposition system has been

made that makes use of a high speed coulometer and a mini computer as a

62
feedback and control mechanism. This system allows for control of deposition

potential while monitoring the charge used in the plating process.

Application of this system to copper-nickel allows for the characterization

of the structure and perfection of superlattices as a function of these

plating parameters. X-ray diffraction data in figure 7 shows the development

of X-ray satellites as a function of the nickel reduction potential. Alloys

produced with the new feedback and control system have demonstrated enhanced

saturation magnetization; Ms , from room temperature to 4 °K. The value of Ms

for the electrochemically produced alloys is higher than measured for any CuNi superlattice produced by the competing technologies of sputtering or

molecular beam epitaxy. This data has also demonstrated that contrary to

current theory there is no magnetic dead layer at the copper-nickel

interfaces. Finally, a new magnetic aftereffect has been observed that

continues for some tens of seconds.

63
Figure 2. Transformation functions of potential (a) and concentration (b)

profiles used to improve the finite difference model convergence.

Figure 1. Comparison of the behavior of uncoated graphite fibers (a) with

Co-W coated fibers (b) in a nickel matrix heated to 800 degrees centigrade.

64
JU3Q ?-92 15.B4

Figure 3. An SEM micrograph and an EDAX trace of a sectioned Ni-Mn

compositionally modulated alloy coating under development for neutron

mirrors

Laboratory AcooUratod Woar Toats

BEPCr

Milky Cr

DC Duplex Cr

PP Duplex Cr

0 10 SO 30

Woar Rato , g.'eyete (tlmos E-OS}

Ml Situ Wear Teste

Figure 4. Laboratory and Insitu

wear test comparison for experimental

high performance wear resistant

chromium electrodeposits.

Figure 5. Comparison between

electrochemically produced

particulate composites with

hardened steel and chromium

coated steel controls.

65
Figure 6. Structure modulated chromium alloys. The layers are the result of

texturing (preferred orientation) of the chromium BCC structure controlled by

the plating parameters.

Figure 7. An X-ray

diffraction pattern of

electrochemically produced

Cu-Ni superlattices showing

how the perfection

(satellite intensity)

increases with nickel

potential

.

66
MAGNETIC MATERIALS Lawrence H. Bennett

The Magnetic Materials Group is concerned with the measurement of the

magnetic properties of advanced magnetic and superconducting materials . The

objectives are (1) to relate the metallurgical, magnetic and electronic

structure to the magnetic and superconducting properties of materials, (2) to

develop new and improved magnetic measurement methods, (3) to develop

magnetic reference standards, (4) to apply magnetic phenomena to the

nondestructive evaluation of materials and structures, and (5) to provide

expertise to industry, universities and other government agencies.

Magnetic materials are important to the commerce of the United States. For

example, the sales of soft magnetic materials (primarily for information and

data storage) amounts to more than 25 billion dollars per year. The sales of

hard magnetic materials (primarily for motors) are more than one billion

dollars per year and have been recently increasing due to the discovery of

supermagnetic rare-earth alloys. Magnetic methods of nondestructive

evaluation are used for quality control practically everywhere steel is used.

The new high- temperature superconductors have important potential

applications, both near-term and future.

FY 88 SIGNIFICANT ACCOMPLISHMENTS

o Transient effects in the magnetic hysteresis loops of the high Tc superconductor YBa2 Cu3 07

_ x were measured at a variety of temperatures. A

dynamic magnetic viscosity ("flux flow"), with a decay time of ~10s, as

well as Anderson-Kim flux creep at larger times, were both observed in the

same sample.

o The local topology of the atoms in the high Tc superconductors was

investigated using a modified Wigner- Seitz construction and shown to

exhibit three-dimensional chemical bonding. The La-Cu-0 type (~40K) and

the Y-Ba-Cu-0 type (=90K) superconductors both were found to display the

same bonding characteristics.

o Thin films of the high Tc superconductor, Bi-Sr-Ca-Cu-O, were deposited by

laser ablation onto a Zr02 substrate. By using the magnetically

modulated-microwave- absorption (MAMMA) technique, we have been able to

show how the film quality is affected by the substrate temperature and the

post anneal. These quality differences are obscured in dc resistivity

measurements

o Mossbauer spectra, as a function of oxygen concentration, of the high Tc superconductor RBa2 Cu3 07

_ x

[ R=Y , Pr , Er] were obtained for samples having

3% Fe substituted for Cu. The results established that the iron acted as

an excellent probe for the anti- ferromagnetism associated with the oxygendeficient samples.

o Magnetic measurements on Ni/Cu compositionally-modulated thin films

produced by the Electrodeposition Group with their improved electroplating

procedure exhibited (1) higher magnetizations and (2) smaller temperature

dependences of the magnetization than any reported previously by any

technique. These results demonstrate that electrodepositing nanometer

thick layers of the highest quality is feasible.
o An experimental system for detailed analysis of the magnetic Barkhausen

noise in commercial steels has been designed and constructed. This

system, which measures the (1) noise pulse amplitude distribution profile,

(2) power spectral density, (3) pulse number spectrum and (4) total noise

power, will provide a scientific basis for the use of Barkhausen noise as

a nondestructive evaluation tool.

o A series of Ag+Fe3 04 thin films prepared by R.F. diode sputtering of a

compositionally split target to intentionally create a composition

gradient in the series of deposits revealed a grain size transition at ~30

wt. % Ag to a nanometer size granular morphology. These nanocomposites

were characterized by Mosabauer spectroscopy, x-ray diffraction and, of

especial importance, field-emission scanning-electron microscopy (FESEM)

.

Compositionallv-Modulated-Allov Thin Films

L. H. Bennett and L. J. Swartzendruber

The Electrodeposition Group has established that it is possible to produce

compositionally-modulated alloys (CMA) with individual layers in the

nanometer range by electrochemical deposition using with an improved

electroplating procedure. A series of magnetic measurements on Ni/Cu

compositionally-modulated thin films produced with this improved

electrodeposition was carried out. The hysteresis loop measured with the

field perpendicular to the plane of the foil showed a coercive force less

than the parallel loop. These foils also exhibited (1) higher magnetizations

and (2) smaller temperature dependences of the magnetization than any

reported previously by any technique. The temperature dependences of the

magnetization tracked the x-ray satellite intensities, as a function of Ni

overpotential (figure 1). These results demonstrate that electrodepositing

nanometer thick layers of the highest quality is feasible and that the

magnetic measurements constitute a meaningful characterization tool for them.

High-Temoerature Superconductors

L. J. Swartzendruber, L. H. Bennett, and R. D. Shull

Among the most technologically significant properties of the new high-Tc superconductors are magnetic flux pinning and the associated critical

currents including their dynamic characteristics. Transient effects in the

magnetic hysteresis loops of the high Tc superconductor YBa2 Cu3 07

_ x were

measured at a variety of temperatures. A dynamic magnetic viscosity ("flux

flow”), with a decay time of ~10s, as well as Anderson-Kim flux creep at

larger times, were both observed in the same sample for the first time. A

major question always is to what extent are these properties intrinsic to the

material and to what extent are they due to the grain boundaries and other

microstructural characteristics. Since high quality single crystals can only

be produced in very small sizes, very sensitive magnetic measurements are

required. As illustrated in figure 2, this capability is now present in the

Metallurgy Division. This figure indicates transient effects in the pinched

central region of the loop. An important new flux "depinning" phenomenon has

also been observed in high- field hysteresis loops in several samples.

The local topology of the atoms in the high Tc superconductors was

68
investigated using a modified Wigner-Seitz construction and shown to exhibit

three-dimensional chemical bonding. The La-Cu-0 type (~40K) and Y-Ba-Cu-0

type (~90K) superconductors both were found to display the same bonding

characteristics. An example of the bonding in two extremes is shown in

figure 3.

Continuing a cooperative program with the Johns Hopkins University Applied

Physics Laboratory, thin films of the high Tc superconductor, Bi-Sr-Ca-Cu-0

were deposited by laser ablation onto a Zr02 substrate. By using the

magnetically-modulated-microwave-absorption (MAMMA) technique, we have been

able to show how the film quality is affected by the substrate temperature

and the post anneal. These quality differences are obscured in dc

resistivity measurements.

Mossbauer spectra, as a function of oxygen concentration, of the high Tc superconductor RBa2 Cu3 07 _ x [R=Y, Pr, Er] were obtained for samples having 3%

Fe substituted for Cu (e.g., see figure 4). The results established that the

iron acted as an excellent probe for the anti -ferromagnetism associated with

the oxygen- deficient samples. In general, the occurrence of a high Tc was

associated with the disappearance of the antiferromagnetism.

Nanocomnosite Materials

R. D. Shull, L. J. Swartz endruber , and L. H. Bennett

Composite materials (immiscible metals and oxides with a size scale of the

order of nanometers) have been shown to possess unusual composition-dependent

electronic and magnetic properties. These materials provide a unique

laboratory for the atomic engineering of specific material properties.

Thin films of immiscible Ag and Fe 3 0A were prepared with varying compositions

by cosputtering (R.F. diode) the two constituents from a compositionallysplit target. A transition to a morphology of nanometer-sized regions of the

two constituents was observed at a composition of -30 wt. % Ag (see figure

5) . This micrograph is the first view of the surface of a nanocomposite

material by means of a field emission scanning electron microscope (FESEM)

[This microscope possesses the very high magnification of the transmission

electron microscope (TEM) , but does not require the special specimen

preparation techniques.] Coincident with the development of nanometer- sized

grains, the magnetic behavior of the thin films also changed. Ferrimagnetism

was observed by Mossbauer spectroscopy for smaller Ag contents, while

superparamagnetic behavior was exhibited by those thin films containing > 30

wt.% Ag. Nanocomposites of Ag+Fe3 0A were also prepared by cosputtering from

mechanically mixed powder targets. However, in this latter case the critical

composition required for the development of superparamagnetic behavior was

only 5 wt. % Ag. The difference in critical compositions in the latter case

is ascribed to the much greater interaction between the species in the

sputtering plasma. These nanocomposite materials have potential for vertical

recording and in magneto-optical information storage.

Another way to prepare nanocomposites, the sol-gel technique, is under

investigation in cooperation with Dr. J. Ritter of the Ceramics Division.

Preliminary x-ray diffraction and Mossbauer data appear encouraging.

69
Magnetic NDE

L. J. Swartzendruber and H. Ettedgui*

*Guest Scientist, Nuclear Reasearch Center - Negev, Israel

Magnetic particle inspection, magnetic flux leakage testing, and magnetic

permeability measurement, are nondestructive evaluation techniques widely

used in industry, the first two for defect detection, and latter for property

determinations such as ferrite content in stainless steel welds. A number of

methods (Barkhausen noise, magnetoacoustic emission, magnetomechanical

damping, and ac magnetometry) have been used on a limited scale but require

further development to increase their reliability and make them more widely

applicable. Finally, some magnetic property measurements (e.g. saturation

magnetization, coercivity, and initial permeability) contain a wealth of

information concerning material properties that has barely begun to be

exploited. Current effort on these techniques in the Metallurgy Division

include magnetic particle inspection standards and Barkhausen noise analysis.

A large number of workers have shown that measured properties of the

Barkhausen noise can be related to material properties such as hardness

,

grain size, internal stress, and defect density. When usable, the Barkhausen

methods is very attractive because high production rates are possible.

However, the relationship between the observed noise and a material property

is always heuristic and is generally poorly understood from a fundamental

point of view which could lead to erroneous conclusions. There are many ways

to characterize Barkhausen noise, including (1) the noise pulse amplitude

distribution profile, (2) the power spectral density, (3) the pulse number

spectrum, and (4) the total noise power. Currently available equipment uses

one or another of these methods to produce a "Barkhausen number" which

changes when a material property changes , but the same method does not appear

to be used by any two pieces of equipment. Our purpose has been to develop

an experimental arrangement which will have the flexibility to calculate

these "numbers" from the characteristics of the observed noise as well as to

allow a detailed analysis of the noise from a fundamental point of view.

This will be accomplished primarily by software analysis of digitized noise

signals. An example of a Barkhausen noise spectrum and a power density

spectrum of this noise obtained using digital techniques is shown in figure

6. A theoretical model of an elementary Barkhausen jump is being examined,

using numerical computer procedures, for evidence of deterministic chaos.

Effort during the coming year will focus on further development of our

Barkhausen system and associated software and on obtaining and analyzing

Barkhausen noise from selected steels with a variety of microstructures. The

goal is to develop materials with very well characterized noise properties

that can be used as standards to compare the output from different types of

noise analyzers.

During the current fiscal year a second version of the military standard for

magnetic particle inspection (MXL-STD- 1949) was prepared and coordinated

(work supported by the U.S. Array Materials Technology Laboratory). Valuable

comments were obtained from over fifty companies. We also are participating

in conversion of this standard to an ASTM document.

70
Magnetization,

emu

- 1.8 Fig . 1. 0.9 -

Saturation magnetization, M(T)

normalized to the saturation

magnetization at T=0, versus

temperature for three different

Ni/Cu multilayer films. All

three were produced by electro

deposition with identical

electrochemical parameters to

produce 440 layers of ~30ANi/

~30ACu, except for changing the

Ni overpotential, as shown.

- 1.6

0.8 -

0.7 -

0.6 -

(0 = - 1.4 Ni

0.5 40 80 120 160 200

Temperature, K

240 280

x 10-5 BYCO Crystal CG3. D. Kaiser

xtal vol. ** 10-^cc dim ~ 340 x 340 x70 m

10 / 20/00

Applied Field, Oe

Fig. 2.

Low- field hysteresis loop in a highquality YBa2 Cu3 07

. x single crystal

weighing about 60 /ig, measured in the

Metallurgy Division's new SQUID

magnetometer

(o) (b)

k C

k c a

Fig. 3. The Wigner- Seitz polyhedron around the Cu(l) atom in the high Tc YBa2 Cu3 07 , calculated using (a) metallic and (b) ionic radii.

71
Fig. 4.

Comparison of the Mossbauer

spectra from two samples of

RBa2 (Cu0 . g7 Fe 003 ) 3 O7

_ x for two

different rare earths (R=Pr and

R=Er) with x~l . The outer two

lines observed for R=Pr (but not

for R=Er) are due to the presence

of a magnetic hyperfine field and

arise from iron atoms substituted

on Cu plane sites. These results

are consistent with the view that

a superconductor is not formed

for R=Pr because the Cu atoms on

the planes in this system form an

antiferromagnetic structure.

RBa 2^ Cu0.97 Fe 0.03^3°7-x

Velocity, mm/

s

Fig. 6.

Power spectrum of Barkhausen

Noise from 20mg sample of Fe foil

measured at room temperature.

The power density spectrum was

obtained from the digitized noise

(as shown in the inset) by taking

the autocorrelation of the fast

fourier transform.

Fig. 5.

Field Emission Scanning Electron

Microscope (FESEM) high magnification

picture (250,000X) of the surface of a

Ag+Fe3 04 nanocomposite containing ~30

wt.% Ag showing the nanometer- sized

regions of silver (light) and iron

oxide (dark) in the thin- film deposit.

For this high magnification picture no

special specimen preparation was

required.

Power spectrum

72

Field,
HIGH TEMPERATURE MATERIALS CHEMISTRY John W. Hastie

The research program in high temperature materials chemistry emphasizes the

thermodynamic, chemical-kinetic, interfacial microstructure, and molecularlevel behavior of inorganic materials in high temperature process and service

environments. Specific current objectives are (1) to support the U.S. Steel

Industry through development of a thermodynamic database and solution model

for prediction of slag, refractory, and inorganic steel inclusion

thermochemistry; (2) to develop and apply (eg., to refractory ceramics and

composites) a new molecular- specific methodology for obtaining thermal and

chemical stability data at ultra-high temperatures (2000 - 5000°C) for the

design of hypersonic transport vehicles and various defense applications;

recent surveys by NMAB and Industry have indicated a critical need for

thermochemical and other materials property data at these temperatures; (3)

to develop process models and basic data for the preparation of

superconducting films using laser or other vapor deposition techniques; (4)

to enhance the utility of superalloy and carbon/carbon composites in high

temperature oxidation environments through mechanistic studies of oxidation;

(5) to obtain phase equilibria, kinetic, and mechanistic data for the

development of stored chemical energy propulsion systems; and (6) to provide

technical support to the NIST-ACerS Ceramic Phase Diagram Data Program

through critical evaluation and modeling of phase diagrams and the

development of computer graphics for computer storage and manipulation of

phase diagrams.

FY 88 Significant Accomplishments

o A thermodynamic model and accompanying database have been developed

for the prediction of detailed composition and phase properties of

multicomponent-multiphase oxide systems. The model has been shown to

be applicable to typical iron-making slags and refractories used in

steel processing. The model database currently contains over 125

phase components and has been successful in predicting high

temperature thermodynamic activities and phase compositions in

mixtures containing up to eight component oxides. Several industries

are beginning to substitute this model for the overly simplistic

chemical models currently used in transport- type processing computer

codes

o The laser- induced vaporization mass spectrometric technique (developed

in-house) has been applied to vapor plumes produced from superconducting YBa2 Cu3 Ox targets. Time resolved mass and optical

emission spectra were obtained for many neutral and ionic species in

the laser generated plume, including bimetallic species. Work is

underway to correlate the plume species with the composition and

superconducting characteristics of thin films prepared by laser

ablation of superconducting targets. Ultrafast signal averaging

(100 MHz) and optical multichannel spectroscopic capabilities have

been added to the laser- induced vaporization facility. These new

techniques permit both mass and optical spectrometric techniques to be

73

. u. » . .. m bb
applied to the study of non- equilibrium processes occurring on the

laser-impact time scale.

o A new mass spectrometric and complementary thermochemical

investigation of the ternary Nb-Al-0 system has been initiated

as part of a cooperative DARPA program with CEBELCOR (M. Pourbaix,

Belgium) and the University of Florida to develop oxidation models of

advanced intermetallics . Activity data on Nb-Al interme tallies and

their oxidation products are being obtained under this study. Also a

preliminary THERMOCALC model of the Nb-Al -0 system has been developed

to guide the experimental work.

o Mass spectrometric investigations of the reactions of high energy

oxidants (F2 and C103 F) with Li-Mg-Al alloys, aluminum, and alumina

have been undertaken in support of the development of new stored

chemical energy propulsion devices by U.S. Industry and DOD. Evidence

for kinetic inhibition of the reactions by formation of oxide or

fluoride protective layers has been found. These effects will have

to be taken into account in development models of successful devices.

o A PC-based computer program for the retrieval and manipulation of

phase diagrams has been developed and released for beta- testing by

industrial and other agency sponsors of the joint NIST-ACerS Phase

Diagrams for Ceramists Data Program. The graphics database and the

program to access it are the result of a long standing collaborative

program between the High Temperature Materials Chemistry Group and the

American Ceramic Society.

Steel Slag - Refractory Thermochemistry

J. W. Hastie, E. R. Plante, D. W. Bonnell, W. S. Horton1

1 Guest Scientist

Modeling and complementary experimental work has continued on the development

of a generic predictive model of iron and steel-making slag and refractory

thermochemistry. The computer model is already in use by several steel and

other industrial laboratories and consortia. In addition to its present

utility for existing steel-making technology, the model is designed to be

applicable to new direct reduction steel making technologies being planned or

under development.

Recent measurements have been made to determine the alkali oxide activity in

a blast furnace slag sample supplied by Inland Steel Co. These data were

obtained using the Knudsen effusion modulated-beam mass spectrometric system.

In addition, as a check on the blast furnace slag measurements, baseline

experiments were conducted using reference basic (high CaO) glasses with

known amounts of alkali. The data are the first measurements on basic slags

and will be used to verify and extend the model calculations. The results

included the K(g) , Na(g) , and 02 (g) partial pressures as a function of

temperature and condensed phase composition.

74
The computer model is quite general and has had excellent success in modeling

a variety of highly complex slags. In application to basic steel-making

slags, we have encountered discrepancies in experimental versus model

results, which are due to uncertainties in the available thermochemical data.

In particular, available Gibbs energies of formation data for the calcium

aluminosilicate liquids in the database (i.e. CaAl2 Si2 08( 1) {anorthite},

CaAl2 Si A 0 12 {calcium leucite), and Ca2 Al2 Si07 (1) { gehelenite } ) are currently

being refined. In addition, although thermodynamic data for mixed alkali

silicates {KNaSi03 (l) and KNaSi2 05 (l)} are unavailable, mixed alkalis are

known to be significant vapor species above mixed alkali systems which

implies the existence of a configurational stability (predominately entropic

at high temperature) for mixed alkalis. Trial species functions have been

introduced into the database and are being tested.

With the expansion of the database to over 150 components covering 18

elements, it has become necessary to develop methods for handling the

database via computer-aided data preparation tools, and permit broader ranges

of temperatures. This has resulted in a new development effort which

includes modifying the equilibrium code SOLGASMIX to permit automated

database use and refitting the entire current database to expand the range of

validity of the thermodynamic functions.

Thermodynamic and Kinetic Stability of Refractory Materials at Ultra-High

Temperatures

D. W. Bonnell, P. K. Schenck, J. W. Hastie

The coupling of laser heating with mass spec trome trie analysis has the

potential for providing quantitative thermochemical and other data for

refractory materials at temperature and pressure extremes heretofore

inaccessible to standard techniques. In addition, degradation of materials

by high powered lasers is important in, for example, the design of laser

fusion processes, laser welding, laser processing of ceramics (most recently,

superconducting and diamond films) , laser etching of semiconductor

components, laser annealing of surface alloys, and in the durability of

refractories in defense and space applications.

We have shown that a Nd/YAG laser system focused to power densities in the

region of 10 8 W/cm2

, is a convenient energy source for producing controlled

vapor plumes with generally negligible post-vaporization perturbation of the

neutral species identities and concentrations. The NIST -LIVMS technique

utilizes time-resolved mass analysis to provide time-of- flight species

specific information on temperature, ionic and neutral precursors, and time

history of the laser heating process. Figure 1 shows the time-of - flight

signals for some of the carbon species emitted from a graphite target. These

multimode signals exhibit both the complexity of the time -of - flight signals

and the need for ultrafast data acquisition and signal averaging. To meet

this need a 100 MHz signal averager has been added to the LIVMS . Earlier

studies of the BN and graphite systems have been extended to include carbide

targets. SiC targets were vaporized and studied by the LIVMS technique.

75

. h L ib JlM' liMn i U\ li iLuJj
Evidence for polymeric (SiC) 2 evolution was found in addition to the expected

decomposition vaporization.

Mechanistic Determination of Superconducting Thin Film Deposition

P. K. Schenck, D. W. Bonnell, J. W. Hastie

A joint project with the Magnetic Materials group was initiated this year to

apply the LIVMS technique to high temperature superconducting targets. Thin

films deposited by laser vaporization from bulk high temperature

superconducting material have shown evidence of high temperature

superconductivity. Time resolved mass spectra were obtained for many neutral

and ionic species in the laser generated plume from YBa2 Cu3 Ox targets,

including bimetallic species CuBa and YCu. Observation of molecular 02 in

the plume is consistent with the oxygen deficiency of laser deposited films

reported by other researchers. This deficiency requires that the films be

annealed at high temperature in 02 to restore the proper stoichiometry for

high temperature superconductivity. A high speed optical multichannel

analyzer was added to the LIVMS facility to allow optical spectroscopic

techniques to be applied to the study of the laser generated plumes. Figure

2 shows the optical emission spectra from the YBa2 Cu3 Ox plume during the

initial vaporization and after 5000 laser shots. The spectra indicate that

the relative amounts of Y and Ba in the plume are lower after several

thousand laser shots. This result suggests that the ablation surface must be

kept fresh to maintain the superconductor Y-Ba-Cu stoichiometry in the plume.

Work is underway to further correlate plume species with the composition and

characteristics of thin films of ceramic superconductors.

Processing and Protection of High Temperature Structural Materials

J. W. Hastie, D. W. Bonnell , .EL^ R . Plante, U. Kattner1

1 Guest Scientist, Metallurgical Processing Group

This activity represents a new group thrust initiated late in FY 88 under a

DARPA sponsored program joint with the University of Florida. An industrial

panel advises the program.

The purpose of this effort is to combine existing thermochemical data with

new experimental determinations and modeling formalisms to develop databanked information and models which provide for improved design and

evaluation of refractory superalloy and composite systems. Niobium alloys

and particularly the Nb-Al-0 system are being investigated initially. Data

are to be obtained on the mechanisms of oxidation, species transport rates,

thermochemical stabilities, activities, vapor phase interactions,

solubilities, and diffusivities for the development of reliable models of

coating/substrate/gas interactions. In the beginning stages, most of the

work has concentrated on the review of sparsely available literature data and

on the development of a heuristic ternary phase diagram to use as an

experimental guide both for NIST and for the University of Florida groups.

In the Nb-Al-0 system intermediate condensed-phase compounds exist: the

binary compounds Nb3 Al, Nb2 Al, NbAl3 , NbO, Nb02 and Nb2 05 and, along the

76
quasibinary Al2 03 -Nb2 0 5 section, four ternary compounds 49Nb2 05 «Al 2 03 , 25Nb2 05 *A12 03 , 9Nb2 05 «Al2 03 and Nb 2 05 «Al2 03 , with the latter two having

significant ranges of homogeneity. For the phase diagram calculation of this

system, the thermodynamic quantities for some phases are unknown or not

enough data are available to determine them, simplifications and assumptions

have been made in the current calculation.

Stored Chemical Energy Systems

E. R. Plante, D. W. Bonnell, L. P. Cook1

1 Ceramics Division

Mass spectrometric determinations of the reaction products of potential

oxidants [C103 F(g) or F2 (g) ] with reactive metals or alloys (Li, Mg, Al) have

been made as part of an ongoing propulsion program sponsored by ONR. The

reaction of C103 F with Li-Al or Li-Al-Mg alloys was observed to form gaseous

Li and Al mixed halides, which need to be included in thermochemical models

of the combustion process. Under laboratory steady state conditions, the Cl2 and 02 gas pressures, from C103 F decomposition, were found to be much greater

than for F2 indicating preferential fluorination of the alloys. However,

there is no evidence for reaction of oxygen with the alloy under low pressure

(10' 5 atm) laboratory experimental conditions. Under higher pressure

conditions (0.3 atm) reaction with oxygen takes place erratically as

evidenced by large fluctuations in the oxygen pressure. Aluminum oxide

reacts with F2 (g) to form A1F3 (g) and 02 (g) , while the addition of Al metal

produces mainly AlF(g) . Some evidence of kinetic inhibition of the reactions

by formation of oxide or fluoride protective layers was observed. Future

work is being directed toward studying the reactions of liquid organic

perfluoro compounds such as perfluoro tetrahydrofuran which has been shown to

react with Al to form AlF(g) and C0(g) . The use of organic fluorides extends

the advantages of safety and high density to the propulsion system.

Phase Diagram Graphics, Evaluation, and Modeling

P. K. Schenck, J. W. Hastie, J. R. Dennis 1

1 ACerS Research Associate

New computer software has been developed to handle complex binary and ternary

diagrams using stand alone desk top computers in support of the Phase

Diagrams for Ceramists Data Program. The publication- ready diagrams for the

recently completed Vol. 6 of "Phase Diagrams for Ceramists" were generated

with this system. Software was also developed to provide PC-access to the

ceramics phase diagram graphics database. PC-users will have the ability to

retrieve data from the screen display in a choice of user units (e.g., °C,

°F, or K)Mixture compositions in binary phase fields can be determined

interactively by use of the lever rule and the results displayed on the PCmonitor screen. The PC-based program and the graphics database for Vol. 6

have been distributed for beta testing to the technical representatives of

the more than twenty industrial sponsors of the joint NIST/ACerS phase

equilibria program. Figure 4 shows the title screen from the distributed PC

software and a typical phase diagram as displayed on the PC monitor screen.

77
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MECHANICAL PROPERTIES OF METALS John H. Smith

The Mechanical Properties of Metals Group was formed during FY 88 by

combining personnel transferred into the Metallurgy Division from the

Fracture and Deformation Division with personnel in the Metallurgy Division

responsible for the microscopic characterization of metals. The mission of

the group is to: (1) characterize the mechanical and physical properties of

metals and metal based materials (2) develop improved test methods for

characterizing the mechanical properties of metals (3) evaluate the

structural integrity and durability of metallic structures and components and

(4) characterize the microstructure and composition of metals and alloys.

The activities of this group are consist of (1) research on the mechanical

properties of metals (2) research on test and calibration methods (3)

structural characterization of materials (4) investigative metallurgy

(failure analysis) and (5) technology transfer. The research on the

mechanical properties of metals consists primarily of special tests to

evaluate the properties of newly developed materials and on tests to evaluate

the structural integrity of metallic components and structures. Most of this

work is supported by other government agencies and involves close

collaboration with industry associations such as the American Association for

Railroads and the Compressed Gas Association and with several individual

companies. The research on test methods and calibration methods is largely

supported by NIST funds and is directed at improved methods for

characterizing the properties of both conventional materials and of new

advanced materials. The structural characterization of materials involves

the development of new techniques and the use of optical and electron

microscopy, image analysis and X-ray analysis to evaluate the microstructure

and composition of metal and alloys. This activity is carried out in

collaboration with and in support of the most of the research being carried

out in metals processing and advanced material in the Division and in IMSE.

The investigative metallurgy (failure analysis) projects are all carried out

at the request of and with funding from other agencies and outside

organizations. These activities lead to a better understanding of how our

metallic structures and components perform in service and frequently lead to

improvement in design codes and materials standards. This group's most

significant activity in technology transfer has been providing the direction

and operation of the Mechanical Failure Prevention Group (MFPG) . For over 25

years, the MFPG has very successfully organized an annual or semiannual

conference and published a proceeding on the analysis, detection, and

prevention of failures in a wide variety of mechanical components.

FY 88 Significant Accomplishments

o An extensive investigation was completed to determine the cause of the

structural collapse of a large oil tank owned by the Ashland Oil Company.

Actions were identified to reduce the probability of similar occurrences

in other large, above ground tanks.

o A major investigation was completed for the Federal Railway Administration

to determine the mechanical properties and fracture properties of steels

used in railroad tank cars. The results of this investigation will permit

accurate determination of critical flaw sizes in tank cars to be

determined.

81
o An investigation of the effects of heat treatment on the mechanical

properties and fracture toughness of HSLA steels or use in naval vessels

was completed.

o A series of investigations to determine the causes of failure of

components in electric power generation was completed.

o The existence of a new form of sustained load cracking in aluminum

pressure vessels was confirmed and procedures were developed to inspect

these vessels.

o The 42nd meeting of the Mechanical Failures Prevention Group (MFPG)

entitled "Technology Innovation -Key to International Competitiveness" was

organized and held. The proceedings of the 41st meeting of the MFPG

entitled "Detection, Diagnosis and Prognosis of Rotating Machinery to

Improve Reliability, Maintainability, and Readiness through Application of

New and Innovative Techniques" was published. The 43d meeting of the MFPG

entitled "Advanced Technology in Failure Prevention" was held in San

Diego Cal.

o A new procedure was developed to use infrared thermography to study crack

initiation and propagation during tensile and fatigue loading in aluminum

and steel.

o A new method for using the electron microprobe for the quantitative

analysis for determining sodium in zinc was developed.

o A study of the formation of high temperature thin film superconductors on

silicon wafers was completed.

o An electron microscope study of the properties of thin film silver- iron

oxide granular metals was completed.

Mechanical Properties Research

G. E. Hicho, J. H. Smith, and T. R. Shives

The mechanical properties of metal research emphasizes the evaluation of

newly developed materials and the evaluation of structural integrity of

metallic components and structures. Increasingly the emphasis is on the

evaluation of advanced metallic materials. Nearly all of this research is

funded by other government agencies and generally involves close

collaboration with the producers and or users of the materials.

Characterization of Railroad Tank Cars Steels - Extensive research has been

conducted to evaluate the mechanical properties, fracture resistance and

crack arrest properties of presently used and new steels for the construction

of railroad tank cars used to transport hazardous materials. Presently used,

as -rolled steels are subject to fracture under some operating conditions when

the tank cars are involved in accidents. However, newly developed

microalloyed steels and new heat treatments of present steels, such as

82
normalizing and stress relieving reduce the possibility of fracture. The

effect of composition, temperature, and strain rate on the mechanical

properties and fracture resistance of the steels have been determined. The

dynamic mechanical properties of AAR M128 and ASTM A212B steels were

determined using Charpy impact tests and dynamic tear tests. The transition

temperature, crack initiation energy, crack propagation energy v and total

fracture energy were determined. For these steels, which are used in

currently existing tank cars, the ductile to brittle transition temperature

was found to be in the range of temperature at which the tank cars are often

used. A review and evaluation was made of new steels for tank cars and of

the feasibility for tank car applications of new microalloyed and controlled

steels based on a comparison of the fracture properties of the new steels

with presently used steels. The fracture toughness of ASTM A- 212 and AAR TC128B in the normalized condition was evaluated as function of temperature to

permit a determination of the critical crack size in railroad tank cars to be

estimated. Additional research was initiated to determine the crack arrest

properties of normalized TC-128B, controlled rolled A808 steel, and

microallyed A710 steel.

Evaluation of HSLA-80 Steels - The effect of heat treatment on the mechanical

properties of newly developed HSLA-80 steel was determined under a program

sponsored by the Navy to determine the feasibility of using these steels for

ship construction. HSLA-80 is a precipitation hardening ferritic steel

containing about 1.2 percent copper for strengthening and niobium for grain

size control.

Safety Design Criteria for High Strength Steel Cylinders - Research is

carried out under sponsorship of the Department of Transportation Office of

Hazardous Materials to establish a sound, technical basis for safety

standards governing the safe design, manufacture, and use of seamless

pressure vessels (cylinders) for the storage and transportation of compressed

gases. Present research is aimed at developing a design criteria for the

construction of high strength steel cylinders to prevent failure by fracture

or by stress corrosion. Collaborative test programs with Taylor Wharton

Inc., Norris Cylinder Inc., and T.I. Chesterfield Ltd. are being conducted to

establish a fracture criteria that accurately predicts the fracture behavior

of thin walled, ductile steel cylinders. Results of this investigation have

led to a preliminary design specification for higher strength steel

cylinders

Sustained Load Cracking in Aluminum Cylinders - A unique form of sustained

load, intergranular has been found in the neck and thread area of type 3AL

aluminum cylinders made from type 6351 alloy. Collaborative investigations

are being carried out with Luxfer USA, Alcan Ltd., and Walter Kidde Inc. to

determine the extent of this form of cracking and to determine which cylinder

designs are subject to fracture and which are subject only to leaking without

rupture. Results of this investigation have resulted in changing from type

6351 alloy to 6061 alloy for the majority of the of new cylinders produced in

the United States.

Evaluation of Aramid Fiber Rope - Under sponsorship of the U.S. Coast Guard,

the effect of service life on the mechanical properties or aramid fiber rope

83
used to support large radio transmitting towers was evaluated. The tensile

strength, fatigue strength, creep, and stress relaxation of ropes were

evaluated before and after exposure to ocean environments. No apparent

degradation due to the environment was found.

Research on Test and Calibration Methods

T. R. Shives , G. E. Hicho , J. H. Smith, and Y. Huang"

* Guest Scientist, Institute of Metal Research, Academia Sinica, China

Macrohardness Test Block Standards - Under partial support from the NIST

Office of Standard Reference Materials and in collaboration with the ASTM

Committee E-28 on Mechanical Testing to conduct an intercomparison of

Rockwell hardness all test blocks and indentors that are marketed in the

United States. The indentors have been characterized by interferometry and

with an optical comparator. Preliminary results of the Rockwell Brale

indentors evaluation have shown substantial variation from the indentor

geometry required by the ASTM specification. This is believed to be the

cause of much of the variability shown in the hardness test results as shown

in Figure 1

.

Infrared Studies of Crack Growth - A new thermographic method based on the

measurement of infrared (IR) emission from the surface of a loaded body was

developed to study the cooling and heating in aluminum and steel specimens

during tensile and cyclic loading. A typical thermogram is shown in Figure

2. This thermogram was used to measure the temperature at any point on the

body relative to the reference temperature T. Figure 2 shows the dynamic

process of the infrared emission for a carbon steel specimen, with a centercut hole, subjected to tensile loading. Prior to yielding, the IR emission

shows that cooling was concentrated in the area of the crack tip. After

yielding, the IR emisson shows that heating the deformed specimen occurs at

the crack tip. The characteristic "butterfly” shape of the plastic zone was

observed to extend immediately to the boundary of the specimen (see image F

in Fig. 2). In Figure 2, the point PT corresponds to the inflection point

marking the boundary between the IR cooling and heating emission regions.

This value is identified as the thermoelastic limit load and is lower than

the 0.2% offset yield strength. Similar tests conducted on fatigue specimens

showed comparable results. In the deformation of metals, the measurement of

this IR cooling emission technique effect could be used to detect the stress

concentration area.

Fracture Toughness of Aluminum using IR and DC Potential Drop Techniques - A

new measurement technique was developed to measure crack iniation and

extension during fracture testing. J- integral fracture toughness tests were

conducted at room temperature on aluminum three -point bend and compact

tension specimens. The ductile-crack-resistance curves were measured using

the multiple specimen method. Crack growth was automatically recorded using

both the potential drop and infrared (IR) vibro- thermographic techniques.

The IR vibro- thermographic technique made it possible to obtain real-time

measurements of both crack initiation and extension during the entire

fracture toughness test.

84
Certification of Ferrite in Weld Standard - A ferrite in weld Standard

Reference Materials (SRM) has been prepared and is ready for certification.

This material is composed of 10% 430 stainless steel (ferritic) blended with

90% 310 stainless steel (austenitic) . Powder metallurgical techniques are

used to prepare these materials. The materiasl are certified by determining

the percent ferrite in each specimen image and x-ray fluorescence analyses.

The certified standard reference materials will be available calibrate x-ray

diffraction equipment that is used in the determination of ferrite in welds.

Structural Characterization

A. J. Shapiro and L.C. Smith

The structural characterization activity provides the management of the

optical microscopy, electron microscopy, and X-ray facilities for the

Metallurgy Division. Most of the activity is conducted in close

collaboration with the other research projects in the Division such as metals

processing, magnetic materials, metal matrix composites, and other advanced

materials. The emphasis has increasingly shifted to the micros tructural

characterization of advanced materials and to developing improved procedures

and techniques to characterize the structure of these materials. Examples of

this work are the investigation of grain boundary migration in MgO-CaO-ZrO,

the evaluation of the structure of thin film Ag-Fe oxide granular metals, and

the structural characterization of thin film high temperature

superconductors. A new method of quantitative X-ray analysis has been

developed to determine the amount of sodium present in alloys of zinc.

High temperature thin film superconductors of YBa2 Cu3 0n were fabricated by

sputter deposition. The effect of process variables such as substrate

temperature, target to substrate angle and the partial pressure of oxygen in

the sputtering atmosphere on the final composition of the thin film

superconductor were determined by X-ray microanalysis.

Composite materials made from nanometer sized particles of metals (e.g. Ag)

and nonmetals (e.g. FeO) are referred to as granular metals. When the

metallic consistutent has a strong magnetic moment, the granular metal

composite is found to have significantly improved magnetic properties

compared with the homogeneous form of the same metals. An extensive

electron microscope study was undertaken to evaluate the microstructure of

these granular metals and establish relationships between the microstructure

and the unique magnetic properties of these materials.

Investigative Metallurgy

J. H. Smith, G. E. Hicho and T. R. Shives

These investigations are done at the request of and funded by other

government agencies or Congressional Committees. These investigations apply

our expertise in the characterization of metals to determine the cause of

failure and to evaluate the structural integrity of metallic components and

structures. The results of these investigations lead to improvement in the

selection and use of materials and to improvement in design and safety codes

and standards.

85
Ashland Oil Tank Failure - A significant part of the Group's effort for this

year was devoted to a major investigation jointly conducted with the NIST

Center for Building Technology to determine the cause of the catastrophic

collapse of a large (4 million gallon) oil storage tank. The collapse of the

tank was caused by brittle fracture originating from a preexisting defect

(Fig. 3a) in the wall of the tank. The material around the defect was

embrittled by heating during the dismantling and reconstruction of the tank.

This resulted in reduction in the fracture toughness of the metal surrounding

the defect and the combination of low temperature at the time the tank was

first filled and the stress created by the oil in the tank was sufficient to

initiate the fracture. As shown in Figure 3b, the tank was being operated at

a temperature substantially below the nil -due tility- temperature (NDT) and

consequently the fracture did not arrest and total collapse of the tank

occurred. The results of this investigation have led to continuing

collaboration with the Environmental Protection Agency and with the American

Petroleum Institute to develop improved design codes, construction standards,

and inspection standards for above ground storage tanks.

Failure Examinations for the Potomac Electric Power Company

During the past year we have presented the Potomac Electric Power Company

(PEPCO) 18 reports on failures that occurred in their power generating

equipment. Our failure analyses consisted of a variety of examinations that

included weld, waterwall, and bolt failures. The results of these

investigations are used by PEPCO to correct operating conditions and prevent

future failures of the same type which reduces down time for the power

generating equipment during peak power demands.

86
ROCKWELL

HARDNESS

(HRC)

Figure 1. Effect of Rockwell C (Brale) Indentor Geometry on

Variability of Hardness Measurement.

0 0-5 1.0 1.5

Load-line displacement

Figure 2. Temperature Distribution at the Tip of a Crack During

Fracture of a Center Cracked Wide Plate.

87
RELATIVE

STRESS

Outside of Tank

First Shell Course Weld Metal

Second

Shell Course

Figure 3a. Defect on Fracture Surface from which Tank Failure

Originated.

Figure 3b. Fracture Analyses Diagram (FAD) showing that Tank was

Operating well below NDT Temperature.

88
PUBLICATIONS

Metallurgical Processing Group

Bendersky, L. A.; "Al-Mn jj. Phase and Its Relation to Quasicrystals." J.

of Microscopy, 146 , 303 (1987).

Bendersky, L. A.; "Quasicrystals and Quasicrystal-Related Phases in the

Al-Mn System." J. of Mat. Sci. and Eng., 99, 331 (1988).

Bendersky, L. A. ; "Structural Relationship Between Crystalline and

Quasicrystalline Phases in Al-Mn System." Proceedings of International

Workshop on Quasicrystals; Mater. Sci. Forum, Vols. 22-24, 151 (1987).

Bendersky, L. A.; Biancaniello , F. S.; Schaefer, R. J.; "Amorphous Phase

Formation in Al70 Si 17 Fe 13 Alloy." J. Mat. Res., 2 (4), 427 (1987).

Bendersky, L. A.; Graves, J. A.; Biancaniello, F. S.; Perepezko, J. H.

Boettinger, W. J.; "Pathways for Microstructural Development in TiAl."

Mat. Sci. and Eng., £8, 265 (1988).

Bendersky, L., A.; Kaufman, M. J.; Boettinger, W. J.; Biancaniello, F. S.;

"Solidification of an 'Amorphous' Phase in Rapidly Solidified Al-Fe-Si

Alloys." J. of Mat. Sci. and Eng., 98, 213 (1988).

Bendersky, L. A.; McAlister, A, J.; Biancaniello, F. S.; "Phase

Transformation During Annealing of Rapidly Solidified Al-based Al-Fe-Si

Alloys." Met. Trans. A; in press (1988).

Bendersky, L. A.; Voorhees, P. W. ; Boettinger, W. J.; Johnson, W. C.; "The

Role of Elastic Energy in the Morphological Development of a Ni-Ti-Al

Alloy." Scripta Met., 22, 1029 (1988).

Bennett, L. H. ; Cahn, J. W. ; Schaefer, R. J.; Rubinstein, M. ; Stauss, G.

H. ; "Icosahedral Symmetry vs. Local Icosahedral Environment in Al-Mn

Alloys from NMR." Nature, 326 . 372 (1987).

Blendell, J. E. ; Handwerker, C. A.; Vaudin, M. D. ; Fuller, E. R. , Jr.;

"Composition Control of the Microstructure of Ba2 YCu3 06+x . " J. of Cryst.

Growth, 89, 93 (1988).

Boettinger, W. J.; "Microstructural Variations in Rapidly Solidified

Alloys." Mat. Sci. and Eng. , 98, 123 (1988).

Boettinger, W. J.; Bendersky, L. A.; Biancaniello, F. S.; Cahn, J. W.

"Rapid Solidification and Ordering of B2 and L21 Phases in the NiAl-NiTi

System." J. of Mat. Sci. and Eng., 98. 273 (1988).

Boettinger, W. J.; Bendersky, L. A.; Schaefer, R. J.; Biancaniello, F. S.;

"On the Formation of Dispersoids during Rapid Solidification of an Al-FeNi Alloy." Met. Trans. A, 19A, HOI (1988).

89
Boettinger, W. J.; Coriell, S. R. ; Trivedi, R. K. ; "Application of

Dendritic Growth Theory to the Interpretation of Rapid Solidification

Microstructures." Rapid Solidification Processing: Principles and

Technologies IV; R. Mehrabian, P. A. Parrish, eds . ; Claitor's Publishing

Division; Baton Rouge, LA; 13 (1988).

Burton, B. P. ; "Application of the e-G Approach to Binary Rhombohedral

Carbonate Systems." Proceedings of CALPHAD-XVII ; in press (1988).

Burton, B. P.; Davidson, P. M. ; "Multicritical Phase Relations in

Minerals." Advances in Physical Geochemistry; S. Ghose, ed.; SpringerVerlag; in press.

Burton, B. P. ; Davidson, P. M. ; "Order-Disorder in Omphacitic Pyroxenes:

A Model for Coupled Substitution in the Point Approximation." Reply

American Mineralogist, 7_3> 916 (1988).

Burton, B. P. ; Davidson, P. M. ; "Short-Range Order and Frustration in

Omphacite." Physics and Chemistry of Materials, 1.5, 570 (1988).

Burton, B. P. ; Kattner, U. ; "The Al-Cu-Pb (Aluminum- Copper Lead) System."

Bull. Alloy Phase Diagrams; in press.

Coriell, S. R. ; McFadden, G. B.; "Double Diffusive Convection during

Directional Solidification: Nonlinear Analysis." Proceedings of Tenth

U.S. National Congress of Applied Mechanics, J. P. Lamb, ed. ; American

Society of Mechanical Engineers; New York, NY; 233 (1987).

Davidson, P. M. ; Burton, B. P. ; "Short-Range Order and Frustration in

Omphacite." EOS, 69, No. 16, 521 (1988).

deWit, R. ; Low, S. R. ; Fields, R. J.; "Ispitivanja Zaus tavlj anj a Prsline

u Sirokim Plocama: Razvoj Eksperimentalnih Postupaka." Perspektive

Razvoja i Primene Mehanike Loma; S. Sedmak, ed. ; Gosa, Belgrade, 201

(1987).

Fong, J. T. ; Fields, R. J., editors; "Basic Questions in Fatigue, Volume

I," ASTM STP 924 (American Society for Testing and Materials),

Philadelphia, 389 (1988).

Handwerker, C. A.; "Diffusion-Induced Grain Boundary Migration." 1989

McGraw-Hill Yearbook of Science and Technology; S. P. Parker, ed. ; in

press.

Handwerker, C. A.; Cahn, J.; "Microstructural Control Through DiffusionInduced Grain Boundary Migration." Polysilicon Films and Interfaces;

Proceedings of Mat. Res. Soc. Symp., 106 . 127 (1988).

Hardy, S. C.; "The Surface Tension of Liquid Silicon." Properties of

Silicon, The Institute of Electrical Engineers, 58 (1988).

Hardy, S. C. ; Voorhees , P. W. ; "Ostwald Ripening in a System with a High

Volume Fraction of Coarsening Phase." Met. Trans. (1988) in press.

90
Kattner, U. ; Burton, B. P.; "The Al-Cu-Bi (Aluminum- Copper Bismuth)

System." Bull. Alloy Phase Diagrams; in press.

Kikuchi, R. ; Burton, B. P.; "Calculation of Some Oxide Systems Using the

Cluster Variation Method." Physica B, 150 . 132 (1988).

Ledbetter, H. M. ; Fields, R. J.; Reno, R. C.; "Texture in Recrystallized

Copper Rod: An Ultrasonic-Velocity, Neutron Diffraction Study."

Proceedings of the Eighth International Conference on Textures of

Materials; Santa Fe (1987); in press.

Lee, D. J.; Vaudin, M. D. ; Handwerker, C. A.; Kattner, U. R. ; "Phase

Stability and Interface Reactions in the Al-SiC System." Proceedings of

Mat. Res. Soc. Symp. for High-Temperature, High-Performance Composites; in

press

Liu, T . - S .

Fields, R. J.; Fariborz, S. J.; Harlow, D. G.; Delph, T. J.;

"Experimental Observations and Analysis of Creep Cavitation in AISI 304

Type 304 Stainless Steel." Acta Met.; in press (1988).

McFadden, G. B.; Boisvert, R. F. ; Coriell, S. R. ; "Nonplanar Interface

Morphologies during Unidirectional Solidification of a Binary Alloy, II.

Three-Dimensional Computations." J. of Crystal Growth, 84, 371 (1987).

McFadden, G. B. ; Coriell, S. R. ; "Solutal Convection during Directional

Solidification." Proceedings of the First National Fluid Dynamics

Congress, paper #88-3635; American Institute of Aeronautics and

Astronautics, Washington, DC; 1572; 1988.

McFadden, G. B. ; Coriell, S. R. ; Alexander, J. I. D. ; "Hydrodynamic and

Free Boundary Instabilities during Crystal Growth: The Effect of a Plane

Stagnation Flow." Communications on Pure and Applied Mathematics, 16., 683

(1988).

McFadden, G. B. ; Coriell, S. R. ; Sekerka, R. F. ; "Effect of Surface

Tension Anisotropy on Cellular Morphologies." J. Crystal Growth, .91 180

(1988).

Mueller, B. A.; Schaefer, R. J.; Perepezko, J.

Al»Mn Powders." J. Mater. Res. ,2, 809 (1987).

'The Solidification of

Murray, J. L. ; McAlister, A. J.; Schaefer, R. J.; Bendersky, L. A.;

Biancaniello , F. S.; Moffat, D. L. ; "Stable and Metastable Phase

Equilibria in the Al-Mn System." Met. Trans. A, 18A . 385 (1987).

Naus, D. J.; Bass, B. R. ; Keeny-Walker , J.; Fields, R. J.; deWit, R. ; Low,

S. R. , III; "Summary of HSST Wide Plate Crack Arrest Tests and Analysis."

Proceedings of the U.S. Nuclear Regulatory Commission Fifteenth Water

Reactor Safety Information Meeting, NUREG/CP-0091 ; Vol. 2; A. J. Weiss,

ed.Office of Nuclear Regulatory Research, USNRC; Washington, DC (1988).

91
Pugh, C. E.; Naus , D. J.; Bass, B. R. ; Nanstad, R. K.; deWit, R. ; Fields,

R. J.; Low, S. R. , III; "Crack Arrest Behavior in Wide Single Edge

Notched Plates of a Light Water Reactor Pressure Vessel." Trans, of 9th

International Conf. on Solid Mechanics in Reactor Technology; Lausanne,

Switzerland; August 17-21; paper Gl-4 (1987).

Pugh, C. E. ; Naus, D. J.; Bass, B. R. ; Nanstad, R. K. ; deWit, R. ; Fields,

R. J.; Low, S. R. , III; "Wide Plate Crack Arrest Tests Utilizing a

Prototypical Pressure Vessel Steel." Int. J. of Pressure Vessels and

Piping, 31 (1988)

.

Reno, R. C.; Clark, A. V.; Blessing, G. V.; Fields, R. J.; Govada, A.;

Thomson, R. B.; Del Santo, P. P.; Mignogna, R. B.; Smith, J. F. ; "Use of

Neutron Pole Figures to Calibrate Ultrasonic Techniques for On-line

Texture Control of Aluminum Plates." Intelligent Processing of Materials

and Advanced Sensors; H. N. G. Wadley, P. A. Parrish, B. B. Rath, S. M.

Wolf; eds . ; The Metallurgical Society; Warrendale, PA; 77 (1987).

Reno, R. C. ; Fields, R. J.; Clark, A. V., Jr.; "Crystallographic Texture

in Rolled Aluminum Plates: Neutron Pole Figure Measurements." Review of

Progress in Quantitative Nondestructive Evaluation; D. 0. Thompson, D. E.

Cimenti, eds.; Plenum, New York, NY; 1439 (1988).

Rhee, W.-H.; Handwerker, C. A.; Yoon, D. ; "The Coherency Strain Induced

Instability of Solid-Liquid Interfaces in the Mo-Ni System." Proceedings

of Mat. Res. Soc. Symp.; Interfacial Structure, Properties, Design; Vol.

122; in press.

Schaefer, R. J.; "Phase Selection in Surface Resolidification." In Rapid

Solidification Processing: Principles and Technologies IV; R. Mehrabian,

ed.; 249 (1988).

Schaefer, R. J.; Bendersky, L. A.; "Metallurgy of Quasicrystals."

Chapter 3 in Aperiodic Crystals; M. V. Jaric, ed. ; Academic Press; (1988).

Sekerka, R. F. ; Voorhees , P. W. ; Coriell, S. R. ; McFadden, G. B.;

"Initial Conditions Implied by t1/2 Solidification of a Sphere with

Capillarity and Interfacial Kinetics." J. Crystal Growth, .87, 415 (1988).

Sims, J. S.; Redmiles, D. F. ; Clark, J. B. ; "ASM/NBS Numerical and

Graphical Database for Binary Alloy Phase Diagrams" in Metallurgical Data

Bases, (American Society for Metals, Metals Park) in press.

Stauss, G. H. ; Rubinstein, M. ; Frieble, E. J.; Bennett, L. H. ; Schaefer,

R. J.; "Nuclear-Magnetic -Resonance Powder Patterns in Al6 Mn, Al4 Mn, and

Al 12 Mn Polycrystals." Phys . Rev. B, .35, 2700 (1987).

Vandiver, P. ; Cort, L. ; Handwerker, C. A.; "Variations in the Practice of

Ceramic Technology in Different Cultures; A Comparison of Korean and

Chinese Celadon Glazes." Advances in Ceramics; in press.

Wheeler, A. A.; Coriell. S. R. ; McFadden, G. B. ; Hurle, D. T. J.; "The

Effect of an Electric Field on the Morphological Stability of the CrystalMelt Interface of a Binary Alloy." J. Crystal Growth, 88., 1 (1988).

92
Advanced Sensing Group

Biendeii, J. E. ; Chiang, Cranmer, D. C.; Freiman, S. W. ; Fuller, Jr., E.

R. ; Drescher-Krasicka , E. ; Johnson, Ward L. ; Ledbetter, H. M. ; Bennett, L.

H. ; Swartzendruber , L. J.; Maronenko , R. B.; Mykleburst, R. L. ; Bright, D.

S. ; and Newbury, D. E.; "Relationship of Electrical, Magnetic, and

Mechanical Properties to Processing in High-Temperature Superconductors in

Chemistry of High-Temperature Superconductors." American Society

Symposium, Series No. 351, 240 (ACS, Washington, D. C.) (1987).

Johnson, W. L. ; Drescher-Krasicka, E.; Blendell, J. E.; Blendell, J. E.;

Chiang, C. K. ; and Wadley, H. N. G.; "Ultrasonic Velocity and Attenuation

in Y1 Ba2 Cu

07

_ x

. " Phys . Rev. Let.; in press.

Kahn, A. H. ; Mester, M. L. ; "An Eddy Current Sensor for the Measurement of

Resistivity and Temperature of Aluminum Rod During Extrusion Processing."

Review of Progress in Quantitive NDE, 6; in press (1988).

eKahn, A. H. ; Mester, M. L. ; and H. N. G. Wadley; "Measuring Internal

Temperatures of Aluminum Extrusion." Proc . 4th Int. Aluminum Extrusion

Technology Seminar, Apr., 1988, Chicago, 111.

Kahn, A. H. ; Lowney, J. R. ; "Valence Band Effective Masses of GaAs , " J.

Appl . Phys., 64, 447 (1988).

Kahn, A. H. ; Danyiuk, S.; Lee, S. W. ; and Ahn, J. H.; "Resistivity of

Linear Scratches in Doped (100) n-type Single Crystal Silicon." J. Appl.

Phys. 63 (9), May 1, 1988.

Kahn, A. H. ; "Boundary Integral Equation Methods for Two Dimensional

Models of Crack Field Interactions." presented at The Technical

Cooperative Program Workshop, Dayton, Ohio, August 1987, (to be published

in J. Nondestr. Eval., (1988-1989).

Norton, S. J.; "Computing Ray Trajectories Between Two Points: A Solution

to the Ray Linking Problem." J. Opt. Soc. Am. A 4, 1919 (1987).

Norton, S. J.; "Mossbauer Imaging." Nature 330 . 151 (12-18 Nov. (1987).

Norton, S. J.; Atzmony, U. ; Swartzendruber, L. J.; Bennett, L. H.

"Mossbauer Imaging: Experimental Result." Nature 330 . 153 (12-18 Nov.

1987).

Norton, S. J.; "Mossbauer Imaging." NBS J. Research 92., 325 (1987).

Norton, S. J.; Simmons, J. A.; Kahn, A. H. ; and Wadley, H. N. G.;

"Research on Inverse Problems in Materials Science and Engineering."

Proceedings of the NATO Advanced Research Workshop on Signal Processing

and Pattern Recognition in Nondestructive Evaluation of Materials, 1987,

Springer -Ver lag.

Norton, S. J.; "Mossbauer Imaging." Physics Bulletin 39>, No. 5 (1988).

93
Norton, S. J.; "Iterative Seismic Inversion." Geophys . J. Roy. Astr. Soc.;'

in press.

Norton, S. J.; "Tomographic Reconstruction of Two-Dimensional Vector

Fields: Application to Flow Imaging." Geoph. J. Roy. Astr. Soc.; in press.

Simmons, J. A.; Drescher-Krasicka , E.; Wadley, H. N. G.; Rosen, M. ; and

Hsieb, T. M. ; "Ultrasonic Methods for Characterizing the Interface in

Composites." Review of Progress in QNDE, Vol. 7, Ed. D. 0. Thompson and D.

E. Chimenti; in press.

Wadley, H. N. G.; Kahn, A. H.; Gefen, Y. ; and Mester, M. L. ; "Eddy Current

Measurement of Density During Hot Isostatic Pressing." Review of Progress

in QNDE, Col. ]_, Eds. D. 0. Thompson and D. E. Chimenti.

Wadley, H. N. G. ; Simmons, J. A.; Drescher-Krasicka, E.; Rosen, M.

;

Clough, R. B. ; Hsieh, T. ; Hirschman, K. ; and Biancaniello , F. S.;

"Composite Materials Interface Characterization." NBSIR 87-3630, March

1988.

Wadley, H. N. G. ; Simmons, J. A.; and Drescher-Krasicka, E. ; "Ultrasonic

Propagation at Cylindrical Metal-Ceramic Interfaces in Composites." MRS

Symposium High Temperature Composites, Ed. F. Lemkey, S. Fishman and A.

Evans, Reno, Nevada; in press (1988).

Wadley, H. N. G.; Biancaniello, F. S.; and Clough, R. B„; "Micromechanical

Studies of Model Metal Matrix Composites." Proc. MRS. Symposium, High

Temperature Composites, Ed. F. Lemkey, S. Fishman and A. Evans, Reno,

Nevada; in press (1988)

.

Wadley, H. N. G. ; Kahn, A. H. ; and Johnson, W. ; "Advanced Sensing of

Materials Processing." MRS Symposium Proceedings, Process Diagnostics;

Materials, Combustion, Fusion, Ed. A. K. Hays, A. C. Eckbreth, G. A.

Campbell, Reno, Nevada, 117 . 109 (1988).

Wadley, H. N. G.; and Rogers, C. D. ; "Internal Discontinuity Sensor Needs

for Steel: Report of Workshop." NBSIR 88-3731, June 1988.

Patent:

Wadley, H. N. G. ; "Method of Determining Subsurface Property Value

Gradient." Patent Number: 4,765,750, August 23, 1988.

Corrosion Group

Anderson, D.B.; Laverty, G.J.; "Corrosion Data for Materials Performance

Characterization." presented at First International Symposium on

Computerization and Networking of Materials Property Databases,

Philadelphia, November 1987, to be published in ASTM Special Technical

Publication.

Anderson, D.B.

;

"Standards for Corrosion Database Development." NACE

Corrosion/88, Paper #119 (1988). ^
Bertocci, U. ; "Modeling of Crack Chemistry in Cu-Au Alloys." J.

Electrochemical Society; in press.

Bertocci, U. ; "Statistics of Localized Breakdown Noise." NACE Sympoium on

Localized Corrosion; in press.

Bertocci, U. ; Pugh, E.N. ; "Modeling of Electrochemical Processes During

Transgranualr Stress Corrosion Cracking of Copper Base Alloys." Proc

International Conference on Metallic Corrosion (1987) .

Early, J.E.; Interrante , C.G.; Low, S.R.; Fields, R.J.; "Dynamic

Mechanical Properties of two AAR-M128 and One ASTM-A212-B Tank Car Head

Plates." NBSIR 88-3690, (1988).

Escalante, E.; "Concepts of Underground Corrosion." ASTM STP 1013 on The

Effects of Soil Characteristics on Corrosion, May 1987; in press.

Escalante, E. ; "Elimination of iR Error in Measurements of Corrosion in

Concrete." ASTM STP on Ohmic Electrolyte Resistance Measurement and

Compensation; May 1988; in press.

Escalante, E. ; "Measuring the Rate of Corrosion of Steel in Concrete."

ASTM STP on Corrosion Rates of Steel in Concrete; June 1988; in press.

Fraker, A.C.; Sung P. ; "Corrosion and Degradation of a Polyurethane/Co-NiCr-Mo Pacemaker Lead." J. Biomed. Mater. Res.: Applied Biomaterials, Vol.

21 No. A3, 287 (1987).

Fraker, A.C.; "Corrosion of Zircaloy, Report to the U. S. Nuclear

Regulatory Commission." Washington, DC; February (1988).

Fraker, A.C.; Harris, J.S.; "Corrosion Behavior of Low Carbon Steel in

High pH Aqueous Media." Report to the U. S. Nuclear Regulatory Commission,

Washington, DC; March (1988).

Hall, D.E."Sintered Lead Negative Plates Made with Leachable Pore

Formers." Electrochemical Society Extended Abstracts, 87°

(1987).

Hall, D.E.; Sarver, J.M.; Gothard, D.O.

"AB5 -Catalyzed Hydrogen Evolution

Cathodes." Proc. Symp . Electochem. Eng. in the Chlor -Alkali and Chlorate

Industries, The Electrochemical Society, Inc. (1987).

Hall, D.E.

Stafford, G.R."The Corrosion Behavior of Electrodeposited

Aluminum-Manganese Alloys." Electrochemical Society Extended Abstracts,

87-2 (1987).

Interrante, C.G.

Escalante, E. ; Fraker, A.C.; Ondik, H. ; Plante, E.

Ricker, R.E.; Ruspi, J.; "Evaluation and Compilation of DOE Waste Package

Test Data." Biannual Report, August 1987 - January 1988, NUREG/CR-4735

4 (1988).

95
Interrante , C.G. (editor); Escalante, E; Fraker, A.C.; Hall, D.E.;

Harrison, S.; Liggett, W. ; Linzer, M. ; Ricker, R. ; Ruspi, J.; Shull, R.

;

"Evaluation and Compilation of DOE Waste Package Test Data." Biannual

Report, February 1987 - July 1987." NUREG/CR-4735 , 3 (1988).

Interrante, C.G. (editor); "Evaluation and Compilation of DOE Waste

Package Test Data: Biannual Report, August 1987 - January 1988."

NUREG/CR-4735, 4, (1988).

Ricker, R.E.; Duquette, D.J.; "The Role of Hydrogen in Corrosion Fatigue

of High Purity Al-Zn-Mg Exposed to Water Vapor." Metall. Trans. A., V19A,

1775 (1988).

Trim, J.D.; Anderson, D.B.; Laverty, G.J.; "The NACE-NBS Corrosion Data

Program." Proc. 10th International Congress on Metallic Corrosion (1987).

Electrodeposition Group

Goldman, A. I.; Long, G. G.; Bennett, L. H. ; Lashmore , D. S.; Kuriyama,

M. ; "Observations of Two Structurally Distinct States in Glassy Ni-P Using

EXAFS." J. Electrochem. Soc. 135, 9, (1988).

Grushko, B. ; Stafford, G. R. ; "The Effect of Mn Content on the

Microstructure of Al-Mn Alloys Electrodeposited at 150 °C." Met Trans.; in

press

.

Lashmore, D. S.; "Annual Review of Materials Science-Invited to Prepare a

Review of the Pulsed Electrochemical Deposition of Alloys"; in press.

Lashmore, D. S„; Dariel, M. P. ; "Electrodeposited Cu-Ni Textured

Superlattices." J. of the Electrochem. Soc., 135, 5, 1218 (1988).

Ogburn, F. ; Brown, H. J.; "Aging Effects on XRF Measurements of Solder

Coatings." J. of the American Electroplaters and Surface Finishers Soc.;

in press

.

Stafford, G. R. ; "The Electrodeposition of an Aluminum -Manganese Metallic

Glass from Molten Salts." Proc. Corr. Electrochem. and Cat. of Metallic

Glasses, Vol.88-1, 172 Meet. Electrochem. Soc., Honolulu, Hawaii (1987).

Stafford, G. R. ; "The Electrodeposition of an Aluminum -Manganese

Metallic Glass from Molten Salts." J. Electrochem. Soc.; in press.

Wheeler, N. S.; "The Effect of Magnesium Complex Ions on the Corrosion

Behavior of Magnesium." Ph.D. Thesis, American University, Dept, of

Chemistry, April 5, 1988.

96
Magnetic Materials

Adrian, F. J., Bohandy, J., Kim, B. F. , Moorjani, K. , Wallace, J.S.,

Shull, R. D., Swartzendruber , L. J., Bennett, L. H., "Magnetic Field

Dependence of the Superconductivity in Bi- Sr-Ca-Cu-0 Superconductors".

Physica C, 156 . 184 (1988).

Atzmony, U. , Swartzendruber, L. J., Bennett, L. H. , Dariel, M. P.,

Lashmore, D. S., Rubinstein, M. , Lubitz, P., "Magnetication and Magnetic

Aftereffect in Textured Ni/Cu Compositionally-modulated alloys. J. Mag.

Magn. Matls . , 69, 237 (1987).

Atzmony, U. , Shull, R. D., Chiang, C. K. , Swartzendruber, L. J. and

Bennett, L. H. , "Constricted Diamagnetic Hysteresis Loops Observed for the

High Tc Superconductors". J. Appl. Phys . 63,, 4179 (1988).

Atzmony, U. , Swartzendruber, L. J. and Bennett, L. H. , "Temperature

Hysteresis and Time Dependent Effect in the Initial Susceptibility of

Rapidly Solidified Monel". Scripta Metall. 22., 721 (1988).

Bennett, L. H. , Watson, R. E., Melamud, M, "The Roles of Atomic Volume and

Disclinations in the Magnetism of the Rare Earth-3D Hard Magnets". J. de

Physique; in press (1988).

Bohandy, J., Adrian, F. J., Kim, B. F. , Moorjani, K. , Shull, R.D.,

Swartzendruber, L. J., Bennett, L. H. , Wallace, J.S., "Magnetic-fieldmodulated Microwave -absorption Detection in a Bi- Sr-Ca-Cu-0

Superconductor". J. of Superconductivity; in press (1988).

Goldman, A. J., Long, G. G. , Bennett, L. H. , Lashmore, D. S. , and

Kuriyama, M. , "Observation of Two Structurally Distinct States in Ni-P

Glasses Using EXAFS". J. of Electrochemical Society, 135 . 8 (1988).

Huang, C. Y. , Shapira, Y. , McNiff, E. J., Peters, P. N. , Schwartz, B. B.,

Wu, M. K. , Shull, R. D. , "Magnetic Hysteresis of High-Temperature

YBa2 Cu3 Ox -AgO Superconductors: Explanation of Magnetic Suspension".

Modern Physics Letter B; in press (1988).

Jones, S. A., Shull, R.D.

McAlister, A. J., Kaufman, M. J.,

"Microstructural Studies of Ti-Al Alloys in the Vicinity of the Eutectoid

Reaction". Scripta Metallurgica , 22, 1235 (1988).

Kim, B. F. , Phillips, T. E. , Green, W. J., Swartzendruber, L. J., Shull,

R. D., Bennett, L. H. , Wallace, J. S., "Superconducting Thin Films of BiSr~Ca-Cu-0 Obtained by Laser Ablation Processing". Appl. Phys. Letter; in

press (1988)

Lundy, D. , Ritter, J., Swartzendruber, L. , Shull, R. D., Bennett, L. H.

"Studies of Magnetic Flux Penetration in a Chemically Synthesized

Bi(Pb)SrCaCuO Superconductor". Physica C; in press (1988).

Melmed, A. J. Shull, R. D., Chiang, C. K. and Fowler, H. A., "Field Ion

Microscopy of the High Tc Superconductor Ba2 YCu3 07 _ x

"

J. Appl. Phys.,

63, 4232 (1988). Q7
Melmed, A. J., Shull, R. D., Chiang, C. K. , and Fowler, H. A., "Possible

Evidence for Superconducting Layers in Single Crystal YBa2 Cu3 07 _ x by Field

Ion Microscopy". Science, 239 . 176 (1988).

Melmed, A. J., Shull, R. D., Chiang, C. K. , and Fowler, H.A., "The Atomic

Fingerprint of YBa2 Cu3 07

_ x

- type High-Temperature Superconductors

Observed by Field Ion Microscopy". Mat. Sci. and Eng., 100 . L27 (1988).

Melmed, A. J., Shull, R. D. and Chiang, C. K. , "Progress in Field Ion

Microscopy Imaging of High-Tc Superconducting Oxides". J. de Physique; in

press ( 1988)

.

Melamud, M. , Watson, R. E. , and Bennett, L. H. , "A Wigner-Seitz LocalEnvironment Study of the High Tc Superconductors". Phys . Rev. B., 38., 4

(1988).

Moorjani, K. Bohandy, J. Adrian, F. J. Kim, B. F. , Atzmony, U. Shull, R.

D. Chiang, C. K. Swartzendruber , L. J. and Bennett, L. H. , "Magnetic

Behavior of Both Superconducting Thin Films and Their Deposition Targets".

J. Appl. Phys., 63., 4199 (1988).

Shull, R. D., Atzmony, U. , Shapiro, A. J. Swartzendruber, L. J., Green, W.

L. and Moorjani, K. , "Magnetic Properties of Thin Film Ag+Iron Oxide

Granular Metals". J. Appl. Phys., 63, 4261 (1988).

Swartzendruber, L. J., "Quantitative Problems in Magnetic Particle

Inspection". QNDE Conf. Proceedings; in press (1988).

Swartzendruber, L. J., Bennett, L. H. , "Mossbauer Hyperfine Fields in

RBa2 (Cuq 97 Fe0 03 ) 3 07 . x Superconductors". J. de Physique; in press

(1988).

Swartzendruber, L. J., Bennett, L. H. , "Mossbauer Study of the Effect of

Oxygen Stoichiometry on the High Tc Superconductor Ba2 (Cuq 9

7

Fe 0 0

3

) 3 07

_ x ". J. of Superconductivity; in press (1988).

Wallace, J. S., Ritter, J. J., Fuller, E. , Bennett, L. H. , Shull, R.D. and

Swartzendruber, L. J., "Synthesis & Magnetic Properties of the BiSrCaCu2 0x 80 and 110 K Superconductors"; in press (1988).

Watson, R. E. , Bennett, L. H. , and Melamud, M. , "Disclinations : The

Magnetism and the Magnetic Anisotropies of the Rare Earth- 3d Transition

Metal Hard Magnets". J. Appl. Phys., .63, 3136-3138 (1988).

Wong-Ng, W. , Cook, L. P, Chiang, C. K. , Swartzendruber, Bennett, L. H.

,

Blendell, J., and Minor, D. , "Structural Phase Transition Study of

Ba2 YCu3 07

. x

"

; in press (1988).

98
High Temperature Chemistry

Cook, L. C.; Plante, E. R. ; Bonneli, D. W. ; Hastie, J. W. ; "High

Temperature Chemistry of Stored Chemical Energy Systems for Propulsion."

NBSIR- 87 - 3601 (1987).

Hastie, J. W. ; Bonneli, D. W. ; Plante, E. R. ; "Experimental and Model

Determinations of Coal Mineral and Slag Phase Equilibria." Proc

Symp . High Temperature Materials Chemistry IV, The Electro-chemical

Society, Pennington, N. J. (1987).

Hastie, J. W. ; Schenck, P. K. ; Bonneli, D. W. ; "Ceramic Thermochemistry

and Kinetics from Laser- Induced Vaporization Mass Spectrometry." Proc.

Symp. High Temperature Materials Chemistry IV, The Electro -chemical

Society, Pennington, N. J. (1987).

Bonneli, D. W. ; Schenck, P. K. ; Hastie, J. W. ; "Laser Induced

Vaporization Time Resolved Mass Spectrometry of Refractories."

Proc. Int. Symp. Laser Processes for Microelectronic Applications, The

Electrochemical Society , Pennington, N. J. (1987).

Hastie, J. W. ; "Measurement Advances and Limitations in High Temperature

Mass Spectrometry." Proc. Fourth National Symposium Mass Spectrometry,

India Institute of Science, Bangalore, India (1988).

Plante, E. R. ; Bonneli, D. W. ; Hastie, J. W. ; "Experimental and

Theoretical Determination of Oxide Glass Vapor Pressures and

Activities." Proc. Int. Conf. Advances in the Fusion of Glass,

Alfred, NY, American Ceramic Society; in press, (1988).

Hastie, J. W. ; Bonneli, D. W. ; Plante, E. R. ; "Experimental and Model

Determination of Coal Mineral and Slag Phase Equilibria and Alkali Vapor

Transport, VIII." Proc. Eng. Foundation Conf. "Mineral Matter and Ash

Deposition from Coal," February 21-26, Santa Barbara, CA; in press (1988).

Hastie, J. W. ; Bonneli, D. W. ; "Thermodynamic Activity Predictions for

Molten Slags and Salts, IX." Proc. 3rd Int. Conf. Molten Slags and

Fluxes, June 27-29, Glasgow, UK (Inst. Metal); in press (1988).

Hastie, J. W. ; "Coupling Mass Spectrometry with High Pressure/High

Temperature Systems." Advances in Mass Spectrometry (Heyden and Sons,

Ltd.) Proc. 11th Int. Mass Spec. Conf., Bordeaux, August 29 - September 2;

in press (1988)

Schenck, P. K. ; Bonneli, D. W. ; Hastie, J. W. ; "Laser Vaporization Mass

Spectrometry of Refractory Materials: Graphite and YBa2 Cu3 0x ."

Journal of the American Vacuum Society Proc. 1988 Joint Int. Laser Science

and American Vacuum Soc. Conf.; in press.

Hastie, J. W. ; Bonneli, D. W. ; Plante, E. R. ; "Experimental

Determination and Model Prediction of Glass Thermochemistry X."

Proc. XV Int. Congress on Glass, Leningrad, USSR, July 2-7; in press

(1989).

99
Schenck, P. K. ; Dennis, J. R. (Acers); "PC-Access to Ceramic Phase

Diagrams." Proc . First Int. Symp. on Computerization and Networking of

Materials Property Databases (SLP1017) ASTM (1988).

Mechanical Properties of Metals

Finn, R. D. ; Shives, T. R. ; Brady, C. H.' Plascjak, P.; Meyer, W. ; Sheh,

Y. ; Larson, S.; "Correlation of Hardness with Radiation Induced Defects in

Metal Foil Windows." Proceedings - Seventh International Symposium on

Radiopharmaceutical Chemistry, Groningen, The Netherlands; in press

(1988).

Finn, R. D. ; Shives, T. R. ; Brady, C. H. ; Plascjak, P.; Meywer, W. ; Sheh,

Y. ; "Microhardness Evaluations of Cycletron Fail Windows." Proceedings - Tenth Conference on the Application of Accelerators in Research and

Industry; in press (1988).

Gross, J. L„ ; Yokel, F. Y. ; Wright, R. G. ; Fanney, A. H. ; Smith, J. H.

;

Hicho, G. E. ; Shives, T. R. ; "Investigation into Ashland Oil Storage Tank

Collapse on January 2, 1988." NBSIR 88-3792 (1988).

Gross, J. L. ; Smith, J. H.; Wright, R. U. ; "Ashland Tank Collapse

Investigation." Journal of Performance of Constructed Facilities; in press

(1988).

Hicho, G. E. ; Fields, R. J.; "Effects of Varying the Austenitizing

Temperature and Cooling Rate on the Ability of HSLA-80 to Achieve a Yield

Strength Comparable to HSLA-80." Journal of Heat Treating; in press

( 1988 ).

Hicho, G. E. ; Smith, L. C. ; "Superheater Sample Taken from Potomac River

Unit 4." Letter Report to PEPCO (October 7, 1987).

Hicho, G. E. ; Smith, L. C. ; "Waterwall Tube Sample Removed from Chalk

Point Unit 2." Letter Report to PEPCO (October 10, 1987).

Hicho, G. E. ; Smith, L. C. ; "First Stage, Second Pass Reheater Outlet

Header Stub Sample Taken from Chalk Point Unit 1

. " Letter Report to PEPCO

(November 23, 1987).

Hicho, G. E. ; Smith, L. G.; "Waterwall Tube Failure, Chalk Point Unit 3."

Letter Report to PEPCO (March 7, 1988).

Hicho, G. E.; Smith, L. G.; "Superheater Tube Failure, Potomac River Unit

3. Letter Report to PEPCO (March 7, 1988).

Hicho, G. E. ; Smith, L. C. ; "Waterwall Tube Sample, Chalk Point Unit 1

.

Letter Report to PEPCO (July 15, 1988).

Hicho, G. E. ; Smith, L. C.; "Chromized Tubes, Morgantown Unit 2." Letter

Report to PEPCO (July 21, 1988).

100
Hicho , G. E.; Smith, L. C.; "Babcock and Wilcox Chromized Tubes." Letter

Report to PEPCO (August 1, 1988).

Hicho, G. E.; Smith, L. C.; "Chromized Tube Removed from Waterwall Panel

in Service in Morgantown Unit 2 since November 1981." Letter Report to

PEPCO (August 3, 1988).

Hicho, G. E. ; Smith, L. C.; "Waterwall Tube Samples, Chalk Point Unit 3."

Letter Report to PEPCO (August 15, 1988).

Hicho, G. E. ; Smith, L. C.; "Benning Road Unit 3 Turbine Bolt Failure."

Letter Report to PEPCO (August 8, 1988).

Huang, Y. ; Hicho, G. E.; Fields, R. J.; "J-Integral, R-Curve Testing of

5052 H112 Aluminum Utilizing DC Potential Drop and Infrared Thermographic

Methods." Proceedings of the Seventh International Conference on Fracture,

Houston, Texas, March 1989.

Huang, Y. ; Hicho, G. E. ; Fields, R. J.; "Infrared Measurements of Heating

and Cooling Emissions in Aluminum and Steel During Tensile and Cyclic

Loading" NBSIR 87-3653, February 1988.

Kreider, K. ; Shapiro, A. J.; "Sputtered Thin Film Y Baz Cu3 02 ."

Proceedings - American Vacuum Society Symposium on High Tc Super

Conducting Thin Films, Oct. 3-7; in press (1988).

McHenry, H. I.; Purtscher, P. T. ; Shives, T. R. ; "Observations of Hydrogen

Damage in a Failed Pressure Vessel." Corrosion Science, 2_7 , No. 10/11,

1041 ( 1987 ).

Shives, T. R. ; "Microhardness and Thickness Measurements on Bullets."

memo report to NIST Law Enforcement Standards Laboratory (Jan. 1988).

Shives, T. R; Smith, L. C.; "Tensile Testing of Vehicle Restrain Devices."

Letter report to the US Secret Service (Dec. 1987).

Shives, T„ R. ; Hardness Measurement on the Lead Core of Two Bullets."

memo report to NIST Law Inforcement Standards Laboratory (Feb. 1988).

Shives, T. R. ; "Interim report on the Results of NBS tests on Aramid Fiber

Rope." Letter report to the US Coast Guard (Feb. 1988).

Shives, T. R. ; "Hardness and Thickness Measurements on Bullets." memo

report to NIST Law Enforcement Standards Laboratory (Sept. 1988).

Shives, T. R. ; Smith, L. C„; "Testing of School Bus Flooring." memo

report to the National Transportation Safety Board (Oct. 1988).

Shives, T. R. ; Mertaugh, L. J.; "Detection, Diagnosis and Prognosis of

Rotating Machinery to Improve Reliability, Maintainability, and Readiness

through Application of New and Innovative Techniques." Proceedings of the

41st Meeting of the Mechanical Failures Prevention Group; in press (1988).

101
Shull, R. D.; Shapiro, A. J.; "Magnetic Properties of Thin Film SilverIron Oxide Granular Metals." J. Appl. Phys . 6_3 C81, 4261 (1988).

Shull, R. D.; Ritter, J. J.; Swartzenduber , L. J.; Bennett, L. H.

;

"Magnetic Properties of Iron-Silica GEL Nanocomposites." Proceedings - Symposium on Multicomponent Ultrasonic Microstructures Materials Research

Society, Boston; in press (1988).

Siewert, T.; Hicho, G. E. ; "Choosing a Welding Procedure to Produce a 10

Meter Long Tensile Specimen." Welding Journal, Feb. 1988, 35

Wright, R. N. ; Smith, J. H. ; "Oil Storage Tank Collapse of Ashland - Floreffe Terminal." Materials Evaluation, April 1988, 508.
INDUSTRIAL AND ACADEMIC INTERACTIONS

The research programs of the Metallurgy Division are designed and carried out

in support of industrial and scientific needs. Specialized facilities within

the Division, including metals processing and nondestructive evaluation,

attract scientists from both academic and industrial organizations for

cooperative research efforts. Interactions with industry, universities, and

professional organizations are viewed as an important element of our work

with collaborative programs, consulting and general involvement with outside

groups being a long standing practice. For example, the Metallurgy Division

has been working for more than 70 years with the steel industry to improve

the durability and performance of alloys.

In 1988, the Division performed collaborative research with many private

organizations through its Research Associate and Guest Scientist programs and

other arrangements. Representative examples of such interactions include:

INDUSTRY

1. ACerS (American Ceramic Society)

Dr. Peter Schenck is collaborating with ACerS and the industrial

sponsors of the NBS-ACerS phase diagram optimization program, in the

development of a graphical phase diagram database for ceramic and other

inorganic systems. During the past year a prototype PC version was

released to ACerS and its industrial sponsors.

2 . ALCOA

A cooperative program with the Alloy Technology Division of ALCOA (Dr.

A.K. Vasudevan) and the Corrosion group is in progress. This program

focuses on the influence of grain boundary precipitates on the

susceptibility of Al-Li and Al-Li-Cu alloys to intergranular stress

corrosion cracking. Samples with differing precipitate size

distributions are prepared at ALCOA and tested at NIST.

3. Aluminum Association

The first phase of the cooperative project of NIST and the Aluminum

Association has been brought to a successful conclusion with the

execution of a plant demonstration of the eddy current sensor

developed for measuring temperature of extruded aluminum products

during processing. The Aluminum Association and NIST have agreed

to continue the project for further two years with the objectives

of measuring temperatures in more complex shapes and of obtaining

information on the non-uniformity of temperature profiles.

Mr. Michael L. Mester will continue as Research Associate for the

Aluminum Association.

103
4.

American Association of Railroads (AAR)

The Railway Tank Car Safety Research and Test Committee of the AAR

Research Progress Institute has established a collaborative research

with the NIST program funded by the Federal Railroad Administration

(FRA) to conduct research on the properties of tank car materials.

5. American Cyanamid Corporation

A joint program between the Electrodeposition Group and American

Cyanamid Corporation is addressing the problem of interfacial

interdiffusion of carbon and nickel at elevated temperatures. The

research is being done by a Research Associate (N. Wheeler) in

collaboration with members of the Electrodeposition Group (D. S.

Lashmore and C. E. Johnson), with others in the Metallurgy Division (A.

Shapiro, C. Handwerker, U. Kattner) , and with the Center for Analytical

Chemistry (K. Pratt)

.

6. American Iron and Steel Institute

The Advanced Sensing Group has continued a strong collaboration with the

American Iron and Steel Institute (AISI) during FY 88. The interaction

began in 1983 with the signing of a memorandum of understanding and

agreement to research and develop ultrasonic approaches for internal

temperature distribution and pipe/porosity sensors for control of steel

processing. The work on the pipe/porosity was completed with the

successful evaluation of a prototype system in FY 86. The sensor was

the recipient of an IR-100 award in FY 87 and is now in routine use in

at least one steel mill. Research continues with the temperature sensor

toward extending interface imaging methods for solidifying bodies to

alloys with extensive regions of liquid-solid coexistence.

7 . Artech Corporation

Electrochemical measurements were conducted as part of a study to

develop a standard test for determining surface condition of metal

dental implants. One of the products of the Artech Corporation is

dental implants.

8. ASM INTERNATIONAL (American Society for Metals)

The technical activities of the joint NIST/American Society for Metals

Data Program for alloy phase diagrams are centered at NIST. The editor

and associate editor of the Bulletin of Alloy Phase Diagrams are

J. B. Clark and B. Burton (both at NIST).

9

.

BDM Corporation

NIST researchers are collaborating with computer scientists at BDM on a

DARPA funded program to develop an Intelligent Processing of Materials

Concept for the Hot Isostatic Pressing of Intermetallic Composites.

104
10. Bethlehem Steel Corporation

Assisted in the evaluation of the Chickasawbogue Bridge failure in

Mobile, AL which collapsed because of corrosion of the supporting steel

piles immersed in aggressive water.

11. Collaborative Testing Services, Inc.

R. J. Fields collaborated with Charles Leete and Sarah Weitzel of

Collaborative Testing Services (CTS) in the selection of materials and

specimen fabrication procedures for the interlaboratory comparison

testing. The areas in which laboratory comparisons were sought were

tensile testing and hardness testing of metals. A method was also

jointly devised to handle gradients of materials properties, as

naturally occur in long bars, in the evaluation and comparison process.

12. Crucible Materials Corp., General Electric Co., and Hoeganaes Corp

An industry-NIST consortium has been formed to conduct research on

automated measurement and control of powder particle size distributions

produced by atomization. Scientists from Crucible Materials, General

Electric, and Hoeganaes, which all are companies strongly interested in

control of fine rapidly-solidified alloy powders, are collaborating in

this consortium work with NIST scientists. The NIST supersonic inert

gas metal atomizer (SIGMA) in the Metallurgy Division's metals

processing laboratory plays a central role in this work. During the

past year the SIGMA has been instrumented to allow real-time

measurements by laser diffraction techniques of powder size

distributions while they are being produced. Methods of measuring and

controlling the liquid droplet formation process are being developed to

allow feedback and automated control of atomization processes.

13. DuPont (Wilmington, DE)

Dr. John Hastie is collaborating with Dr. U. Klabunde and others of

DuPont on the development of process mechanisms for titanium

extractive metallurgy.

14. FIBA, Inc. and Union Carbide Corporation

A collaborative effort is underway between FIBA, Inc. (P. Horrigan)

Union Carbide Corporation (R. Tripolet) , and NIST (J. H. Smith) to

evaluate use of acoustic emission techniques for use in the periodic

inspection of large steel pressure vessels. NIST is in the process of

developing specific procedures and test criteria to permit the use of

acoustic emission techniques for this application.

15. General Electric Co.

The Advanced Sensing Group is collaborating with the Aircraft Engines

Division of G. E. to explore potential methods for microstructure

105
characterization during processing, for sensing the liquid-solid

interface during "skull" melting of superalloys and applying acoustic

emission techniques to detect residual stress induced microcracking in

intermetallic composites.

16. General Electric Co.

A cooperative investigation on the resistance of NIST (D. S. Lashmore

,

D. R. Kelley and C. E. Johnson) coated fibers to high temperature

degradation is underway.

17. General Electric Co.

In an innovative study, the Metallurgical Processing Group and General

Electric Co. (S. Miller) performed a cooperative project to apply

holographic techniques to visualize the break-up of molten alloys into

fine droplets in the NIST high pressure atomization system. This was

the first application of holography to atomization processes involving

incandescent metals. The extremely short 20 ns laser pulses used in

this work provided stop-action pictures never before obtained of this

dynamic atomization process.

18. Hoeganaes Corporation

Measurements of the surface tensions of molten steel, its dependence on

temperature, and how these vary as a function of alloying content were

performed by a guest scientist from Hoeganaes Corp. in collaboration

with S. G. Hardy of the NIST Metallurgical Processing Group. These

surface tensions are important in controlling liquid droplet formation

during production of steel powder by atomization processes.

19. IBM Corporation

An investigation of the magnetic properties of electrochemically

produced superlattices is underway under IBM sponsorship

.

(L. H. Bennett, D. S. Lashmore and R. R. Oberle)

20. Inland Steel

Drs. Plante and Bonnell have been collaborating with Dr. H. Pielet

of Inland on the thermochemistry of blast furnace and steel slags and

inorganic inclusions in steel. Dr. Pielet provides slag samples and

data from plant experience, Dr. Plante is providing thermochemical

data from high temperature mass spectrometry, while Dr. Bonnell supplies

database and model techniques.

21. Luxfer USA, Inc.

A collaborative effort between NIST ( J . H. Smith) and Luxfer USA, Inc.

(G. Waite) is ongoing to determine the extent of cracking in seamless

aluminum compressed gas cylinders and to develop a reliable test method

for inspecting the cylinders in service.

106
22. Materials Technology Institute of the Chemical Process Industries

MTI, in conjunction with the NACE-NIST Corrosion Data Center (D.B.

Anderson), has initiated a project to develop expert systems for

selection of materials for storage and handling of hazardous chemicals.

Systems are based on rules defined during discussions with consultant

experts representing a broad range of industrial experience and are

structured to meet the needs of materials specialists involved in

design, maintenance and expert assessments. MTI has assigned a Research

Associate (C. P. Sturrock) to work in the Data Center as program leader

with a goal to develop a minimum of three modules over a thirty month

period.

23. Martin Marietta Corporation

Ward L. Johnson and Haydn N. G. Wadley are collaborating with

John Ahearn at Martin Marietta to explore the possibility of

detecting threading misfit dislocations at Si-GaAs think film

interfaces using internal friction methods. If successful, it will

be considered as a potential sensor approach for controlling

interfacial dislocations during molecular beam epitaxy of thin film

compound semiconductors on silicon substrates.

24. NASA/Cal Tech Jet Propulsion Lab (Pasadena, CA)

Dr. Bonnell is collaborating and consulting on design of levitation

systems for space applications.

25. National Association of Corrosion Engineers

The NACE-NIST Corrosion Data Center (D.B. Anderson) continues to provide

the scientific and technical coordination to the joint program to

provide evaluated corrosion data in computerized format. NACE continues

to provide a full time Research Associate at NIST plus considerable

staff time in support of the program activities. Initial software

programs have been well received by industry, with over 600 copies being

sold by NACE in the first year. Current activities involve standards

activity through ASTM and NACE relating to data formatting, expert

system developments for industrial clients, structuring of a

comprehensive corrosion database and data entry from two key industrial

data collections, development of data evaluation techniques and

resolution of technical deficiencies with the corrosion thermodynamics

program. Several additional client supported programs are currently

under negotiation.

26. New Zealand Department of Scientific and Industrial Research

A cooperative program within the NACE-NIST Corrosion Data Center has

been initiated to develop expert systems for materials selection for a variety of critical applications in support of the developing oil and

gas industry in New Zealand. The program leader, K.A. Lichti, a

107
Research Associate from DSIR, is concentrating on materials for

subsurface pumps and valves as a function of well defined environmental

variables. Basic guidelines are being developed through a review of a

wide variety of industrial standards with expert assistance in specific

interpretations

.

27. Norton Corrosion Limited, Inc., Bothell, WA

E. Escalante supervised and consulted with Norton Corrosion on their

application of the computer controlled device, developed in our

laboratories, for measuring the corrosion of reinforcing steel in

concrete bridge decks.

28. Norris Cylinder, Inc.

A collaborative effort between NIST ( J . H. Smith) and Norris Cylinder,

Inc. (E. McSweeney) has been initiated to develop light weight high

strength steel cylinders and more efficient stainless steel cylinders.

29. Pepco

The Division (G. E. Hicho) has performed numerous failure analyses for

the Potomac Electric Power Company (PEPCO) for two reasons: (1) to

assist the public utility in its service to the community and (2) to

maintain and upgrade NIST competence in materials technology for the

electric power industry. As the average age of U.S. plants increases

and failures become more frequent, such competence will be needed to

identify and transfer state-of-the-art technology to industry.

30. Pratt and Whitney

Haydn Wadley and Robert Schaefer (Processing Group) are collaborating

with Pratt and Whitney to determine the HIP mechanism map for a range of

intermetallie alloys being considered for high temperature applications

in future hypersonic aircraft.

31. Solution Model Database

Groups currently using or evaluating the IMCC model include Dr. Howard

Pielet, Inland Steel; Prof. K. S. Spear, Penn State University;

Dr. Chad Sheckler, Alfred University; Prof. Paul Daves, Brigham Young

University; Prof. Steve Benson, Univ. North Dakota; Prof. Tom Roberts,

Milwaukee Area Technical College; Dr. C. David Rogers, USS of USX and

Camegie-Mellon Institute; Prof. Arthur E. Morris, University of

Missouri -Rolla.

32. Superconix, Inc.

A collaborative project is underway with C. F. Gallo, Superconix, Inc.

and the Magnetic Materials Group (L. J. Swartzendruber) to measure the

magnetic properties of superconducting single crystals.

108
33. Technology Transfer Workshops

R. Ricker presented experimental results obtained at NIST on nickel

aluminide corrosion and stress corrosion cracking at a technology

transfer workshop at Oak Ridge National Laboratory. The workshops,

oganized by ORNL, brought together participants from several companies

interested in production, fabrication, and use of nickel aluminide

alloys, as well as university and government research scientists.

34. The International Group for Historic Aircraft Recovery (TIGHAR) , Mr.

R.E. Gillespie, Wilmington, DE

Twelve days before Lindberg's successful crossing of the Atlantic Ocean,

two French aviators attempted to fly from France to New York. They

never arrived at their destination. It was rumored that they had lost

their way and crashed in Maine. TIGHAR believes that they have located

the crash site, and they have collected evidence to support this

possibility. After 75 years, little of the aircraft is expected to be

found, however, TIGHAR found magnetic material at the site that they

asked us to examine the material for possible evidence of metals.

Using the scanning electron microscope and x-ray fluorescence, the

materials was found to contain high concentrations of iron (75.3%) and

manganese (5.9%). The material was not metallic, and these

concentrations can be found in natural occurring minerals. A more indepth study is necessary to identify the material. No funding.

35. USX/Carnegie-Mellon

Dr. Rogers of Carnegie-Mellon Institute (formerly U.S. Steel of USX) is

developing process models for melt shop use. Dr. Bonnell is working

with Dr. Rogers to develop a form of the NIST Steel Slag Model for use

as the chemistry component of such process models.

36. Winston-Salem Fire Marshall's Office

Gas from a leaking pipe caused an explosion that demolished a building

in North Carolina, and the Corrosion Group was approached to investigate

the possible cause of the leak. Examination of the materials brought to

us indicated that one section of pipe had undergone extensive corrosion

damage. Other sections of pipe failed by mechanical overload from

falling debris caused by the explosion. These findings were reported to

the Fire Marshall's office for use in their investigation.

37. Zimmer Company, Warsaw, IN

The effects of composition and heat treatment on the mechanical

properties of the alloy, Ti-6Al-4V, were studied. The Ti-6A1-4V is used

for orthopedic prosthetic devices, and Zimmer is a manufacturer of

surgical implants. Transmission microscopy and microstructural analyses

of specimens with small compositional changes, heat treated specimens

and failed specimens were conducted at NIST.

109
INDUSTRY/UNIVERS ITY

1 . BHABHA Atomic Research Center (Government of India)

University of Poona

A cooperative project is underway with the BHABHA Atomic Research Center

(Dr. C. K. Gupta) and the University of Poona (Dr. A. P. B. Sinha)

.

This project is part of the Indo-US Physical, Materials and Marine

Sciences Collaboration Program and the objective of this project is to

study the influence of nitrogen content on the stress corrosion cracking

behavior of stainless steels (alloy 316L) . NIST has provided material

for this study and complimentary experiments will be conducted at the

various institutions. A workshop on the Corrosion Science and

Technology on Stainless Steels is being planned to be held in India.

2. Lehigh University/Intergraph Corp.

R. J. Fields continued his collaboration with Dr. T. -S. Liu of

Intergraph and Prof. T. J. Delph of Lehigh on the quantification of

creep damage in metals. Results of recent work were published in Acta

Metallurgica. R. J. Fields is now measuring cavities in-situ using

synchrotron radiography. The bicrystals for this work are creep

stressed at Lehigh University.

3. NIST Metals Processing Laboratory

The Metals Processing Laboratory of the National Institute of Standards

and Technology contains facilities for preparation of special samples

not readily obtainable elsewhere. Scientists from industry and

universities can come to NIST to help prepare samples for independent or

collaborative research. During the past year, investigators from

Crucible Materials, General Electric, National Aeronautics and Space

Administration, Johns Hopkins University, University of California, and

University of Wisconsin have participated in interactions in this

program.

4. SRI (Stanford Research International)

Drs. Hastie and Bonnell are collaborating with Dr. D. Hildenbrand of

SRI in the mass spectral analysis of complex high temperature vapors.

NIST and SRI are using techniques which are unique to each laboratory

but are nevertheless complementary.

UNIVERSITIES

1. Applied Physics Laboratory, The Johns Hopkins University

A collaborative effort is underway between the Applied Physics

Laboratory of the Johns Hopkins University (K. Moorjani) and NIST

(R. Shull) to prepare and investigate the magnetic behavior of composite

materials having nanocrystalline-sized grains.

110
2. Applied Physics Laboratory, The Johns Hopkins University

A collaborative effort is underway between the Applied Physics

Laboratory of the Johns Hopkins University (J. Bohandy) and NIST

(L. Bennett) to prepare high Tc superconductors by laser ablation and

investigate their magnetic properties.

3. Ben-Gurion University

A Joint U.S. Israeli Binational Science Foundation program on solid

state amorphization transformations is underway between NIST (D. S.

Lashmore) and Ben-Gurion University (M. P. Dariel)

4. Boris Kidric Institute (BKI) , Belgrade, Yugoslavia

A collaborative activity is underway between Dr. Hastie and Dr. Zmbov

of BKI for the mass spectrometric analysis of complex high temperature

processes, including plasma deposition of amorphous silicon.

5. Cambridge University

Professor Michael F. Ashby and graduate students at Cambridge University

(England) are developing predictive models for the hot isostatic

pressing of intermetallic composites in collaboration with Metallurgy

Division scientists.

6. Carnegie Mellon University

NIST and General Efeetrrc'"re searchers are collaborating with Professors

M. Fox and I. Hultage in CMU's Robotics Institute to explore the

application of artificial intelligence techniques in design/redesign of

• materials processing pathways.

7. Free University of Brussells

Drs. Hastie and Bonnell are collaborating with Dr. J. Drowart

(Brussels) on a survey of ionization cross section usage in

high temperature mass spectrometry.

8. Georgia Institute of Technology

Professor Shui-Nee Chow and coworkers are developing new mathematical

techniques for studying dynamical systems and applying them to the

spinodal decomposition of alloys.

9. George Mason University

Professor Raymond Chapman and coworkers are exploring new methods of

conflict resolution and applying them to the development of multi -group

research programs such as DARPA's program on Innovative Concept for

Design (DICE).

Ill
10. George Washington University

George Hicho serves as an Associate Professorial Lecturer in Engineering

at George Washington University in the area of Mechanical Properties

testing

.

11. Indira Gandhi Institute (IGI) Kalpakkara, India

A collaborative activity is underway between Dr. Has tie and Dr. Mathews

of IGI for the mass spectrometric investigation of materials at very

high temperatures generated by laser heating.

12. Institute of Metals Research, Academia Sinica, Shenyang

A collaborative effort is underway with a guest scientist, Prof.

Y. Huang, of the Institute of Metals Research, Academia Sinica,

Shenyang, Peoples Republic of China, to investigate the fracture of

metals using infrared thermography and DC potential drop techniques to

measure crack length.

13. Johns Hopkins University

Studies on the mechanism of transgranular stress corrosion cracking

have been pursued in cooperation with Johns Hopkins University

(Dr. J. Kruger). The experimental studies were carried out at NBS by

a graduate student (T. Cassagne) , and the staff of the Corrosion Group

was involved both in the experimental and in the analysis of the

results

.

14. Johns Hopkins University

A joint investigation of the mechanical properties of electrodeposited

CMS alloys is being conducted with Johns Hopkins University in

cooperation with Dr. Moshe Rosen. (D. S. Lashmore and R. R. Oberle)

15. Johns Hopkins University

A collaborative effort with Johns Hopkins University (D. Shectman) which

resulted in the discovery of an entirely new class of materials, the

quasicrystals, was continued. Emphasis has been on studies of the

structure of these unusual alloys and the processing conditions that

produce them.

16. Korean Advanced Institute of Standards and Technology

A collaborative effort is underway between Alexander Shapiro of the

Metallurgy Division and a guest scientist, Prof. Duk H. Yoou, of the

Korean Advanced Institute of Standards and Technology (KAIST) to study

grain boundary migration in (6 MgO + 4 CuO) + 90 Zr02.

112
17. Northwestern University

Studies of coarsening rates in Pb-Sn solid- liquid mixtures are being

performed cooperatively with Northwestern University (P. Voorhees) . The

aim of this work is to test and develop general rules that will be

applicable to a large variety of metallurgical processes.

18. Oregon Graduate Research Center

A collaborative effort has been initiated between NIST ( J . H. Smith) and

the Oregon Graduate Research Center (Prof. Atteridge) to develop test

methods and standards for fracture resistant high strength steel

cylinders

19. Rice University

Dr. Bonnell continues to provide consultation support to the High

Temperature Group in the Chemistry Department on levitation and

thermophysical properties of liquid metals.

20. University of Maryland

R. deWit and R. J. Fields collaborated with G. R. Irwin and X. J. Zhang

of the University of Maryland in the understanding of cleavage crack

arrest and reinitiation in steel. Quantitative topological of fracture

surfaces from wide-plate crack-arrest test were made at NIST and

analyzed at the University of Maryland. These topographies provided

corroboration for the very high crack arrest toughness found in the

tests. Continued interaction with University of Maryland seeks to

correlate reduction- in- thickness contours measured at NIST with the

topographic results.

21. University of Pennsylvania

R. J. Fields collaborated with Prof. David Pope and John Benci of the

University of Pennsylvania in the quantification of creep damage in nonuniform, multiaxial stress fields. Bars of a heat-resisting, ferritic

alloy containing notches of varying acuity were creep damaged to various

degrees. Synchrotron x- radiographs were made in the region of the

notches. Quantitative image analysis of these radiographs permitted

contours of constant creep damage to be determined around the notches.

Such quantitative damage maps are making possible the critical

assessment of various creep damage theories.

22. University of Science and Technology - Beijing, China

In a program funded by the United Nations Industrial Development

Organization (UNIDO) , a seminar series on corrosion database development

was provided by D. B. Anderson at UST-Beijing to an audience of students

and corrosion researchers from throughout China. The program has also

113
funded a fellowship for a Guest Researcher (Dr. Changrong Li) for a one

year visit in the Corrosion Data Center where her goal is to develop a

prototype database addressing key Chinese industrial development needs.

23. University of Wisconsin at Madison

Studies of microstructure development and phase diagram relationships in

intermetallics have been expanded and applied to new materials as a

result of cooperative programs underway with J. Perepezko and A. Chang

of the University of Wisconsin.
TECHNICAL/PROFESSIONAL COMMITTEE LEADERSHIP ACTIVITIES

Alpha Sigma Mu, The Metallurgy and Materials Honor Society

R. E. Ricker, National Board of Trustees

American Association for Crystal Growth

S. R. Coriell, Executive Committee

American Electroplaters and Surface Finishers Society

C. E. Johnson, Electrocomposites Committee

D. S. Lashmore , Alloy Deposition Subcommittee

American Institute of Mining, Metallurgical and Petroleum Engineers

The Metallurgical Society

J. B. Clark, The Physical Metallurgy Committee

J. B. Clark, The Physics and Chemistry of Materials Committee

R. E. Ricker, Committee on Corrosion and Environmental Effects

H.N.G. Wadley, Secretary, Materials Design and Manufacturing Division

American Petroleum Institute

Task Group on Tankage Brittle Fracture

J. H. Smith

Applied Mechanics Reviews

H.N.G. Wadley, Associate Editor

ASM INTERNATIONAL

Alloy Phase Diagram Appropriations Committee

E. N. Pugh

Alloy Phase Diagram Data Committee

J. B. Clark, Chairman

Corrosion and Environmental Effects Committee

R. E. Ricker

Editorial Committee for Advanced Materials and Processes

E. N. Pugh

Materials Science Division Council

J. B. Clark

NDT Committee

H.N.G. Wadley

Subcommittee on Metallurgical Reactions and Electromigration in

Electronic Devices

C. A. Handwerker, Chairman

115
Technology Transfer Committee

E. N. Pugh

Washington, DC Chapter - Education Committee

R. E. Ricker, Chairman

ASTM

Committee on Terminology

C. G. Interrante , Technical Committee Representative

Coordinating Group on Terminology for Environmental Activities

C. G. Interrante, Convener

B5

:

Copper and Copper Alloys

L. J. Swartzendruber

B7

:

Light Metals

R. D. Shull

Wo J. Boettinger

B8

:

B8.10:

Metallic and Inorganic Coatings

General Test Methods

G. E. Johnson

Do S. Lashmore

B8. 10.03: Microhardness Testing

Go E. Johnson, Liaison to E04

Do So Lashmore, Liaison to E04

C26:

C26 . 07

:

Nuclear Fuel Cycle

Waste Materials

Co G. Interrante

C26 . 13

:

Repository Waste Package Materials Testing

Co Go Interrante, Leader, Task Group on Terminology

E3

:

E3.07:

Chemical Analysis of Metals

Acoustic Emission

Ro C. Clough

E4:

E4.05:

Metallography

Microhardness

C„ E. Johnson

Do So Lashmore

Eh Nondestructive Testing

Lo J. Swartzendruber

L. Ho Bennett

E7 : 04 Acoustic Emission

Jo A. Simmons

R. C. Clough

116
E24

Fracture Testing

C. G. Interrante, Member of Executive Committee

E24 : 02 Fractography and Associated Microstructures

G. E. Hicho

E24 . 04

Sub-Critical Crack Growth

C. G, Interrante

E24.05: Terminology for Fracture Testing

C. G. Interrante, Co-Chairman

R. deWit, Secretary

E24.06: Fracture Mechanics Applications

J. H. Smith

G. E. Hicho

E28

E28.06.07:

Mechanical Testing

Hardness Test Block Intercomparison Task Group

T. R. Shives , Chairman

E49

Computerization of Material Property Data

D, B. Anderson, Steering Committee for Second International

Symposium on Computerized Materials Databases

E49 .02.5: Corrosion Data Formats

D, B. Anderson, Chairman

E49 : 91D. B, Anderson, Awards Committee Chairman

F4:

F4.02.09:

Medical and Surgical Materials and Devices

Joint Section on Corrosion of Implants

A, C, Fraker, Co-Chairperson

F7

F7 o 04:

Aerospace Industry Methods

Hydrogen Embrittlement Testing

G, G, Interrante, Chairman, Task Group on Terminology

Gl:

Gl ,03 . 1

Corrosion of Metals

Corrosion Data Formats Task Group

D, B, Anderson, Chairman

Gl ,06: SCC and Corrosion Fatigue

R, E, Ricker

C. G. Interrante

Gl , 10

Corrosion of Metals in Soil

E, Escalante

Gl.10.01: Measurement of pH of Soil

E. Escalante, Task Group Leader

117
Gl. 10.02: Measurement of Soil Resistivity

E. Escalante

Gl.ll: Electrochemical Measurements in Corrosion

R. E. Ricker

Gl . 14 Corrosion of Steel in Concrete

E. Escalante

G1.99: D. B. Anderson, Liason to ASTM Committee E-49

Electrochemical Society

Deposition from Non-Aqueous Electrolytes Symposium

G. R. Stafford, Co-Chairman

Electrodeposition Division

D. S. Lashmore , Chairman, Editor

Hydrogen Production and Storage Symposium Co-Chairman

D. E. Hall

Industrial Electroytic Division

D. E. Hall, Vice Chairman and Executive Committee

Symposia Subcommittee

D . S . Lashmore

Federation of Materials Societies

S. R. Coriell, Trustee

High Temperature Science Journal

J. W„ Hastie, Editorial Board Member

International Advisory Committee and Program Committee for International

Conference on Rapidly Quenched Metals

W. J. Boettinger, Member

International Committee for Conference on Hot Isostatic Pressing

R. J. Schaefer, Chairman

International Standards Organization

TC107: Metallic and Other Non-Organic Coatings

C. E. Johnson, Delegate

TC107o02: Methods of Inspection and Co-Ordination of Test Methods

C. E, Johnson, Delegate

TC107.03: Electrodeposited Coatings and Related Finishes

C. E. Johnson, Delegate

118
TC164

Mechanical Testing

1. Terminology

C. G. Interrante, Delegate

International Union of Pure and Applied Chemistry Commission II -3

High Temperature and Solid State Chemistry

J. W. Hasties, Titular Member

Maryland Institute of Metals

W. J. Boettinger, Executive Board Member

Materials Science and Engineering

L. H. Bennett, Associate Editor

Mechanical Failures Prevention Group

T. R. Shives, Executive Secretary and Editor of Proceedings

National Aeronautics and Space Administration

High Temperature Advisory Committee

D, W« Bonnell, Member

National Association of Corrosion Engineers (NACE)

T.3 Corrosion Science and Technology Committee

T,3E: Unit Committee on SCC and Corrosion Fatigue

R. Ricker

T.3K: Corrosion and Other Deterioration Phenomenon Associated

with Concrete

E. Escalante

T„3L: Unit Committee on Electrochemical Techniques

R. Ricker

T.3U.1: Task Group on Corrosion Data Formats

D. B. Anderson, Chairman

NACE Board of Directors

E. N. Pugh, Ex Officio Member

NACE Research Committee

E. N. Pugh, Chairman

NACE-NIST Corrosion Data Program

Administrative Committee

D. E. Hall

D. B. Anderson

Board of Trustees

E. N. Pugh

NACE Baltimore -Washington Chapter Executive Committee

R. Ricker, Membership Committee Chairman

119
National Research Council

Transportation Research Board

E. Escalante, Panel Member

Office of Energy-Related Inventions, National Bureau of Standards

L. H. Bennett, Reviewer of Invention Disclosures

J. H. Smith, Reviewer of Invention Disclosures

Society for Biomaterials Standards

A. C. Fraker, Standards Representative on the ASTM F4 Committee

Society of Automotive Engineers/ASTM

Unified Numbering System for Metals and Alloys

L. H. Bennett, NBS Representative

U.S. Department of Transportation

Technical Hazardous Liquid Pipeline Safety Standards Committee

R. J. Fields, Secretary

1989 International Conference on High Temperature Materials Chemistry

J. W„ Has tie, Chairman

D. W. Bonne 11, Vice Chairman

120
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NBS-T T4A 1 rev. 2 - 8 C) U.S. DEPT. OF COMM. 1 . BIBLIOGRAPHIC DATA

SHFFT (Cea In srmrfinn S)

PUBLICATION OR 2. REPORT NO.

NISTIR 88-3843

Performing Organ. Report No. 3. Publ i cation D ate December 1988

Institute for Materials Science and Engineering;

Metallurgy Division, Technical Activities 1988

5. AUTHOR(S)

6. PERFORMING ORGANIZATION (If joint or other than N 8S, see in struction s) 7. Contract/Grant No.

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE 3. Type of Report & Period Covered

WASHINGTON, D.C. 20234

9c SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, City . State, ZIP)

10. SUPPLEMENTARY NOTES

3 Document describes a computer program; SF-185, FlPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information. I f document includes a significant

bibliography or literature survey , mention it here)

This report summarizes the FY 1988 activities of the Metallurgy Division of the

National Institute of Standards and Technology (NIST) . The research centers upon the

structure—processing-properties relations of metals and alloys and on the methods of

their measurement. The activities also include the generation and evaluation of

critical materials data. Efforts comprise studies of metallurgical processing,

corrosion, mechanical properties, electrodeposition, process sensors, high temperature

reactions and magnetic materials.

The work described also includes four cooperative programs with American professional

socities and industry: the National Association of Corrosion Engineers (NACE) - NIST

Corrosion Data Program, the Aluminum Association - NIST Temperature Sensor Program,

the American Iron and Steel Institute (AISI) - NIST Steel Sensor Program, and the

ASM INTERNATIONAL (ASM) - NIST Alloy Phase Diagram Program.

The scientific publications, committee participation, and other professional interactions of the 79 full-time and part-time permanent members of the Metallurgy Division

and its 48 guest researchers are identified.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolon s) Corrosion; Electrodeposition; Magnetic Properties; Metals Processing; Metallurgy;

Process Sensors

13. AVAILABILITY 14. NO. OF

PRINTED PAGES

XI Uni imited

:

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! Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

20402. 15. Price

i_X| Order From National Technical Information Service (NTIS), Springfield, VA. 22161 $18.95

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