i

Materials Science and

Engineering Laboratory

FY 2004 Programs and

Accomplishments

Metallurgy

Division

Carol A. Handwerker, Chief

Frank W. Gayle, Deputy

NISTIR 7127

September 2004

National Institute of

Standards and Technology

Arden L. Bement, Jr.

Director

Technology

Administration

Phillip J. Bond

Undersecretary of

Commerce for Technology

U.S. Department

of Commerce

Donald L. Evans

Secretary
ii

Certain commercial entities, equipment, or materials may be identified in this document in order to

describe an experimental procedure or concept adequately. Such identification is not intended to imply

recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended

to imply that the entities, materials, or equipment are necessarily the best available for the purpose.
iii

Table of Contents

Table of Contents

Executive Summary ...................................................................................................................1

Technical Highlights...................................................................................................................3

Formation of Glass by a First Order Transition ..................................................................4

Interactions with Industry: Delivering Data and

Standard Test Methods for Sheet Metal Forming...............................................................6

Breakthroughs in Magnetic Refrigeration...........................................................................8

Grand Challenges in Nanomagnetics: High Coercivity FePt

Alloys for Future Perpendicular Magnetic Data Storage .................................................10

On-Chip Interconnects:

Extending Performance of Sub-100 nm Lines .................................................................. 12

The Structural Steel of the World Trade Center Towers ..................................................14

Advanced Manufacturing Methods .........................................................................................16

Sheet Metal Forming for Automotive Applications:

Anelasticity and Springback Prediction ............................................................................17

Microstructural Origins of Surface Roughening

and Strain Localizations ....................................................................................................18

Plasticity, Fabrication Processes, and Performance .........................................................19

Standard Tests and Data for Sheet Metal Formability .....................................................20

The NIST Center for Theoretical and Computational

Materials Science ..............................................................................................................21

Underlying Processes of Plastic Deformation in Metal Alloys ........................................22

High Speed Machining ...................................................................................................... 23

Mechanisms for Delivery of Thermodynamic and Kinetic Data .....................................24

Phase Field Modeling of Materials Systems:

Simulation of Polycrystalline Growth ................................................................................ 25

Hardness Standardization: Rockwell, Vickers, Knoop .....................................................26

Nanometrology ........................................................................................................................27

Nanoscale Characterization by Electron Microscopy....................................................... 28

Nanostructure Fabrication Processes:

Patterned Electrodeposition by Surfactant-Mediated Growth .......................................... 29

Nanostructure Fabrication Processes:

Thin Film Stress Measurements........................................................................................30

Nanomechanics: Coupling Modeling with Experiments...................................................31
iv

Table of Contents

Biomaterials .............................................................................................................................32

USAXS and USAXS Imaging of Biomaterials.................................................................33

Materials for Electronics .........................................................................................................34

Combinatorial/Phase Diagram Approach for

Metallization to Wide-Band-Gap Semiconductors ............................................................35

Lead-Free Surface Finishes: Sn Whisker Growth ...........................................................36

Lead-Free Solders and Solderability .................................................................................37

Electrical Properties of On-Chip Interconnections ...........................................................38

Nanomagnetodynamics .....................................................................................................39

Electrodeposited Pt1–x(Fe,Co,Ni)xAlloys .........................................................................40

Novel Magnetic Materials for Sensors and

Ultra-High Density Data Storage .....................................................................................41

Discovery of Spin Density Waves in a Ferromagnet: Fe-Al ........................................... 42

Safety and Reliability ...............................................................................................................43

Analysis of Structural Steel in the World Trade Center....................................................44

Standard Test Methods for Fire-Resistant Steel ...............................................................45

Pipeline Safety: Corrosion, Fracture and Fatigue ............................................................46

Frangible Bullets and Soft Body Armor ............................................................................47

Marine Forensics and Preservation of Historic Shipwrecks ............................................ 48

Kinetic Penetrators and Amorphous Metals.....................................................................49

Metallurgy Division FY04 Annual Report Publication List .....................................................51

Metallurgy Division .................................................................................................................. 59

Research Staff.........................................................................................................................60

Organizational Charts ..............................................................................................................61
1

Executive Summary

Executive Summary

This report describes the major technical activities

and accomplishments in the Metallurgy Division of

NIST Materials Science and Engineering Laboratory

in FY 2004 (October 2003 through September 2004).

In this report, we have tried to provide insight into how

the capabilities of the NIST Metallurgy Division are

being used to solve problems important to the national

economy and the materials metrology infrastructure,

and how we establish new programs in response to

changes in national priorities. We welcome feedback

and suggestions on how we can better serve the Nation

and encourage increased collaboration to this end.

Mission

Our mission is to provide critical leadership in the

development of measurement methods, standards, and

fundamental understanding of materials behavior needed

by U.S. materials users and producers to become or

remain competitive in the changing global marketplace.

As a fundamental part of this mission, we are

responsible not only for developing new measurement

methods with broad applicability across materials

classes and industries, but also for working with other

federal agencies and industrial sectors to develop and

integrate measurements, standards, software tools, and

evaluated data for specific, important applications.

Establishing Priorities

We examine a wide range of research opportunities

and set priorities based on the following criteria:

the match to the NIST mission, the magnitude and

immediacy of industrial need, the determination that the

NIST contribution is critical for success, the anticipated

impact relative to our investment, the ability to respond

in a timely fashion with high-quality output, and the

opportunity to advance mission science. We make

such decisions using a variety of methods, including

roadmapping activities, workshops, technical meetings,

standards committee participation, and consultation

with individuals representing U.S. industry and other

federal agencies.

Technology trends strongly influence the technical

directions addressed by NIST. We prefer to work

in rapidly evolving technologies, where advances

in measurement science are needed to understand

the limitations on system behavior, and, thus, our

contributions are likely to have a substantial impact on

the course of technology. For NIST as a whole and

the Metallurgy Division in particular, we are committed

to having an impact on nanotechnology, homeland

security, health care, and information technology.

Over the last two years, we have shifted substantial

resources into the areas of nanomagnetics,

nanomechanics, and the application of thermodynamics

and kinetics to nanostructure fabrication, and into

a new MSEL Program in Safety and Reliability of

Infrastructure Materials with a focus on homeland

security and critical infrastructure protection.

The Division highlights and the individual project

descriptions demonstrate our rapid progress in

these and other longer-standing areas.

Research Portfolio

Our 2004 research portfolio focuses on fulfilling

current and future measurement needs of the magnetic

data storage, microelectronics packaging, automotive,

optoelectronics, and energy distribution industries,

on establishing national traceable hardness standards

needed for international trade, and on developing new

measurements that could underpin nanotechnology

development. Our output consists of a variety of

forms, from a fundamental understanding of materials

behavior to measurement techniques conveyed through

the scientific literature and oral presentations, standard

reference materials, evaluated data and online databases,

software tools, and sensors for on-line process control.

Division Structure and Expertise

The Division is composed of 34 scientists,

supported by 5 technicians, 6 administrative staff

members, and more than 80 guest scientists, and

it is organized into five groups that represent the

Division’s core expertise in Metallurgical Processing,

Electrochemical Processing, Magnetic Materials,

Materials Structure and Characterization, and

Materials Performance. However, by virtue of the

interdisciplinary nature of materials problems in the

industrial and metrology sectors that we serve,

Program teams are assembled across group, division

and laboratory boundaries and with external partners

to best meet project goals. We are committed to

assembling the expertise and resources to fulfill our

technical goals with the speed and quality necessary

to have the desired impact.

Recognition for Division Staff

We are proud of the accomplishments of the

Metallurgy Division staff in delivering the mission

science tools — measurements, standards, data,

modeling — needed by our customers. In FY2004,

Division members were recognized for the impact and

quality of their work by a wide range of organizations,
2

Executive Summary

including the award of two Gold Medals, the highest

honor conferred by the Department of Commerce, and

one Silver Medal from the Department of Commerce

and NIST.

■ Bill Egelhoff was awarded a 2003 Department of

Commerce Gold Medal for his world leadership in

the science and engineering of magnetic thin films.

His contributions to the understanding of magnetism,

electron transport and thin film deposition have been

made possible by his Magnetic Engineering Research

Facility, which has enabled him to measure and

control the deposition processing conditions better

than anyone else in the world. Bill has earned an

international reputation as a leader in this field and

has produced significant economic benefits to the

U.S. magnetic data storage industry.

■ Carol Handwerker, Ursula Kattner, Bill Boettinger,

Maureen Williams, Frank Gayle, Frank Biancaniello,

and Tom Siewert were awarded the Department

of Commerce Gold Medal for their scientific and

technical leadership in providing the microelectronics

industry with the critical measurements, modeling,

and data necessary for the successful world-wide

conversion to lead-free solder in microelectronics

manufacturing.

■ Richard Fields was awarded the Department

of Commerce Silver Medal for his important

contributions to the science of materials property

measurements and modeling. His work has resulted

in the recognition of NIST as an important source

of expertise and leadership by other government

agencies and the industrial sector when materials

performance questions need solutions.

■ Ursula Kattner was named a Fellow of ASM

International for her outstanding achievement in

thermodynamics and the application of phase

diagrams to important industrial metallurgical

processes.

■ Bob McMichael was named an IEEE Magnetics

Society Distinguished Lecturer for 2004.

Carol A. Handwerker

Chief, Metallurgy Division
3

Technical Highlights

Technical Highlights

The following Technical Highlights section includes

expanded descriptions of research projects that have

broad applicability and impact. These projects generally

continue for several years. The results are the product

of the efforts of several individuals. The Technical

Highlights include:

■ Formation of Glass by a First Order Transition

■ Interactions With Industry: Delivering Data and

Standard Test Methods for Sheet Metal Forming

■ Breakthroughs in Magnetic Refrigeration

■ Grand Challenges in Nanomagnetics: High Coercivity

FePt Alloys for Future Perpendicular Magnetic

Data Storage

■ On-Chip Interconnects: Extending Performance

of Sub-100 nm Lines

■ The Structural Steel of the World Trade

Center Towers
4

Technical Highlights

Formation of Glass by a First Order Transition

Recently the aerospace, military and electronics

industries have devoted much effort to the

development of practical materials that are

100 % bulk metallic glass but do not require

extremely rapid quenching. Most glassy solids

are thought to be kinetically frozen liquids,

thus the usual approach is to cool fast enough to

prevent formation of crystals. We have presented

evidence that an isotropic non-crystalline metallic

phase (dubbed “q-glass”) in the Al-Fe-Si system

forms during rapid cooling of the melt by a

first order transition, like a crystalline phase,

suggesting the possibility of low-energy,

non-periodic structures and the formation

of glasses by relatively slow growth.

Leonid A. Bendersky and John W. Cahn

Much DoD research has focused recently on

the development of bulk metallic glasses

(e.g., DARPA SAM program) for use as both armor

materials and kinetic penetrators. Production of such

glasses requires moderate rates of melt quenching

in contrast to the rapid quenching required for

conventional metallic glasses. These studies have

all assumed that the glassy phases form only as a

frozen liquid. In order to gain an understanding of

the processing routes available to control these and

related materials, it is essential to determine how

these structures actually form. Such distinctions in

the formation of various glassy phases may play an

important role in their relative ductility, corrosion

resistance and stability. The compositional and

structural nature of the glassy phases is, thus,

a question of more general interest.

An Unusual Microstructure

Found in Rapidly Solidifed Al-Fe-Si

Recently we presented evidence that an isotropic

non-crystalline metallic phase (dubbed “q-glass”) could

be formed by growth from a melt. This phase is the

first phase, or “primary phase,” to form in the Al-Fe-Si

system during rapid cooling of the melt.[1] There is

strong evidence that this phase forms from the melt

by a first order transition. According to transmission

electron microscope (TEM) observations, Figure 1a,

the q-glass nucleates from the melt as isolated

particles, which initially grow as spheres (nodules).

The diffraction pattern taken from a nodule shows it

to be an isotropic glassy phase, Figure 1c. Dark field,

Figure 1b and high-resolution TEM imaging, Figure 2,

also support the isotropic, but highly speckled, nature

of the phase. There is a nucleation barrier, which

implies an interface between the glass and the melt.

Further evidence for the first order transition is found

in the solute partitioning at this interface; the q-glass

rejects Al into the melt, which ultimately solidifies as a

eutectic composed mainly of crystalline fcc aluminum

and more q-glass. Presumably glass and melt are

distinct phases with an interface having a positive,

surface-free energy. Such solidification microstructures

are familiar and well understood, except that here the

glass is the first phase growing from the melt and

eventually becomes surrounded by eutectic, instead

of being the last phase (sometimes the only phase)

formed when atomic motion ceases in the melt.

Figure 1: a) Microstructure of an Al91Fe7Si2 alloy after

electron-beam surface melting with scan velocity of 50 cm/sec.

b) Dark field image of a nodule and the glassy phase in the

monotectic, obtained by positioning a SAD aperture on the

strongest diffuse ring in c).
5

Technical Highlights

Figure 2: High-resolution TEM image showing an interface

between a glassy nodule (q-glass) and Al. Note the isotropic

phase contrast of the q-glass.

Q-Glass Properties

Stability. A lower entropy implies a higher degree

of order, which in turn is consistent with a process

of growth that selects some components and rejects

others. This seems to be the case for the q-glass where

Al is rejected into the melt. The lower entropy implies

that at low temperatures the q-glass may have greater

stability than a conventional glass (frozen liquid) of the

same composition, and that there would be a latent heat

associated with its formation which, as is true for all

incongruent freezing, is spread over a freezing range.

The q-glass in Al-Fe-Si is metastable, as were the

original AlMn quasicrystals. Based on the quasicrystal

experience, it is expected that, in time, fully stable

q-glasses will be found in systems with more

components.

Structure and Order. The implied order and

narrower composition range are closely related.

We expect q-glasses to have a chemical order with

a smaller set of local environments. Recently,

there have been many advances in creating orderly

arrangements which are not crystalline.[2] This work

suggests that it might be possible that a glassy structure

is composed of unit cells which are not parallelepipeds

and cannot be packed in a periodic or quasiperiodic

way. Unlike the pinwheel tilings in two dimensions

which take on every orientation but need matching rules

to prevent them from packing periodically, there are

3-D Schmitt–Conway–Danzig tiles which can fill space

only in an aperiodic way.[2] If atoms pack into such a

unit cell, q-glasses could be stoichiometric and have

low entropy, as do crystalline compounds.

There is some confirmation for such order in

hydrogen-storage alloy glasses. For these glasses, the

charging and discharging pressure have a long plateau,

just as for crystals. This unusual behavior for glasses

implies a highly ordered glass structure in which there

is only one type of site for the stored hydrogen.

On-Going Work

The concept of q-glass was introduced at the MRS

meeting last year at “Symposium MM: Amorphous and

Nanocrystalline Metals.”[1] Since then, our work has

received support from the Air Force Office of Scientific

Research. Current work is focused on three areas:

1. Metastable Al-Fe-Si phase diagram. The ternary

Al-Fe-Si phase diagram has been extensively studied.

Thermodynamic principles of metastable phase

equilibria are well developed, and much is already

known about metastable crystalline phases in this

ternary system, but not about the q-glass. We are

investigating conditions for q-glass formation and

its subsequent conversion to other phases to map

out the bounds of q-glass on the metastable phase

diagram. In addition, calorimetric studies are

being conducted to evaluate the thermodynamics

of q-glass formation.

2. Other glass forming Al-based systems. Judging

from the current literature, it is possible that the

q-glass forms in other Al-based systems.[3] We use

morphological criterion to distinguish the formation

of q-glass from conventional glass, with a special focus

on systems known for forming metallic glasses.

3. Other methods of growing q-glass. Feasibility

studies to fabricate and study the formation and

stability of metallic glasses will be conducted using

combinatorial methods. Libraries of amorphous

metal thin films will be fabricated using the new

Metallurgy Division e-beam evaporation system by

depositing elemental wedge-shaped layers controlled

by moving shutters. This combinatorial approach

will be applied to measuring the stability and control

of glasses.

For More Information on this Topic

1. J.W. Cahn and L.A. Bendersky, “An isotropic glass

phase in Al-Fe-Si formed by a first order transition,”

MRS 2003 Proceedings.

2. M. Senechal, Quasicrystals and Geometry, New

York: Cambridge University Press, Chap. 7, (1995).

3. A. Inoue, M. Watanabe, H.M. Kimura, A. Nagata,

and T. Masumoto, Matls. Trans., 8, 723 (1992).
6

The automotive industry’s push to incorporate

lighter sheet metal parts into new car designs

has been hampered by lack of detailed data on

mechanical behavior for forming. The Metallurgy

Division has developed new metrology and test

methods to address specific problems identified

by industry as inhibiting broad adaptation of

high-strength steel and aluminum sheet in

automotive applications.

Tim Foecke, Mark Stoudt, and Mark Iadicola

The Sheet Metal Forming program within the

Metallurgy Division has been designed from the

outset to be relevant to the American manufacturing

sector. Surveys conducted by NIST staff through the

Industrial Liaison Office (ILO) sought to determine

which aspects of sheet metal forming were most in

need of better data and metrology. The results revealed

that industry had a clear understanding of how NIST

expertise could be applied and predicted a high potential

impact if the research was successfully implemented.

The U.S. automotive industry estimates that the

costs associated with the inability of the finite element

models to adequately predict friction, multiaxial

hardening, or springback are on the order of hundreds

of millions of dollars annually. These shortcomings

are the direct result of insufficient property data and

the physical understanding that such data can reveal.

The projects described here are specifically designed

to address the quality of the sheet metal property data

and models used to develop predictive finite element

models of forming operations.

The Microstructural Origin of

Roughening and Strain Localization

Surface roughness is a major contributor to friction

during sheet metal forming, and thus must be well

controlled in order to obtain a consistent product.

Furthermore, the surface qualities of the finished product

determine ultimate aesthetic characteristics of the vehicle.

Ability to accurately characterize surface roughness

is, therefore, of critical importance to the industry.

There are many sources of error in surface

roughness measurements. Recent studies of the

discrepancies between measured and predicted surface

roughness show that the greatest error is introduced

by the numerical tools used routinely by industry to

interpret the roughness data. Parameters such as

the rms roughness (Rq) compress complex surface

details into singular expressions that do not adequately

represent the surface features involved (Figure 1).

Changes in the surface feature arrangement, which

are not captured by the rms roughness, have a greater

influence on friction. Hence, any prediction of friction

that is based solely on a tool such as the rms roughness

is likely to yield erroneous results.

Interactions with Industry: Delivering Data and

Standard Test Methods for Sheet Metal Forming

Technical Highlights

Figure 1: Two surface conditions exhibiting the same roughness

mathematically, but very different appearances and frictional

behaviors.

These results were presented to the automotive

industry at several major research conferences in the

past year. Invited presentations included talks at the

“2004 Society of Automotive Engineers World Congress”

in Detroit, MI, the “2004 North American Deep

Drawing Research Group” spring meeting at NIST,

the “Springback Compensation Program” and the “Agile

Flexible Binder Control” quarterly meetings held at the

U.S. Council for Automotive Research (USCAR) in

Southfield, MI, as well as the “Automotive Sheet Steels

Symposium” in Chicago, IL. The results were also

published in both archival journal and in conference

proceeding formats.

Overall, the industrial response has been very

positive, and there is a high level of interest in the

outcome of new studies. The high-resolution

surface topography data obtained with the Metallurgy

Division’s scanning laser confocal microscope has been

particularly well received and has stimulated several

new opportunities identified by our industrial contacts

for direct collaboration with the automotive industry.

Multiaxial Flow Surfaces and

Stress-Based Forming Limit Curves

An X-ray stress measuring system was recently

installed on the sheet metal formability station. This

unique instrumentation allows for the direct, in situ
7

measurement of the stress in a given direction while the

sample is under multiaxial load. This year, the multiaxial

stress–strain surfaces have been mapped for three

aluminum sheet alloys of particular interest to the

automotive industry: AA5182, AA6111 and AA6022.

With this experimental system, shown in Figure 2,

we have made the first-ever recorded measurements

of the biaxial hardening exponent. These data will

provide a substantial advantage to industry, allowing the

replacement of current practices that estimate biaxial

flow behavior from a series of extrapolated uniaxial

tensile tests. This new approach is expected to enable

more accurate designs and greater cost savings.

Press releases and technical articles have brought

these new capabilities to the attention of industry. Visits

and inquiries from companies such as ISG-International

Steel Group, Volvo, and Avesta–Polarit have stimulated

the exploration of mutually beneficial research that can

produce enabling data and new insights into formability.

Accumulated plastic strain has been used for

decades to describe the deformation limits of sheet

metal. However, this formalism does not account for

path dependence (i.e., how deformation response

depends on how it is deformed). Stress, on the other

hand, is an intrinsic property of metals, and the ability

to describe a process in terms of critical stresses rather

than strains would remove the dependence on path.

Recent work at GM suggests that this approach would

greatly improve finite element predictions by better

defining the safe working envelope of the materials.

Still needed are direct measurements of multiaxial flow

surfaces, measurements that only NIST can provide.

A collaboration with GM has been developed using

these new data to remove the pure isotropic and

kinematic hardening models currently in use.

Improvements to the modeling and limit formalisms

will be directly transferred to the auto industry.

NUMISHEET 2005

A triennial international conference focusing on

simulation techniques for sheet metal forming die design

will be held in Detroit in 2005. An integral part of this

conference is a round-robin simulation exercise where

various modeling groups try to predict the final shape

of a prototypical forming operation. NIST has been

asked to take the key role of measuring material

properties and then forming the prototype part.

This year, the new NIST capability to measure stresses

in situ has allowed an increase in the complexity and

sophistication of the round-robin simulation. Prediction

of both through-thickness residual stresses in a sheet

that has undergone multiple forming operations and

the stresses in orthogonal directions in a sheet under

load in a die have become vital components of the

benchmark for the conference, representing a

“next-level” challenge for modelers to predict.

Springback Prediction

“Springback,” during and after forming operations,

limits the accuracy and consistency of the final part.

The cup test for measuring springback is a fairly recent

development and has not been completely characterized.

NIST development and testing of the springback cup

test has now been largely completed. A collaboration

with U.S. Steel has shown that computer models that

have been recently modified to account for springback

can now accurately predict the final geometry of the

sample. More significantly, the models come close to

predicting the residual stress profiles that NIST has

measured with neutron and X-ray diffraction.

Working with ASTM and industry, NIST has

submitted the flat-bottomed springback cup test for

consideration as a standard measurement protocol

for the capacity for elastic springback. A committee,

led by Ford and including both material suppliers

and end-users, will consider this new test. Data

generated by NIST on the robustness of the test

and the sensitivity to experimental variations will

form the basis of round-robin analyses.

For More Information on this Topic

L.E. Levine (Metallurgy Division, NIST);

T. Gnäupel–Herold, H. Prask (NIST Center for

Neutron Research); M. Shi (USS); E. Chu (ALCOA);

C. Xia (Ford); T. Stoughton, M. Wenner, C.T. Wang

(GM); A. Lin (Univ. of Illinois)

Technical Highlights

Figure 2: Newly installed X-ray stress measuring system as it

takes data on sheet metal being deformed in biaxial tension.
8

Technical Highlights

Breakthroughs in Magnetic Refrigeration

In the past 10 to 15 years, there has been a

substantial effort to find alternative cooling

technologies to vapor compression systems.

This has been driven largely by the need to

reduce the high energy costs of present systems

along with their use of harmful CFC refrigerants.

Magnetic refrigeration technology is one such

alternative. In principal, because it is a reversible

process, magnetic cooling should be more efficient

than the competing irreversible vapor compression

systems. However, magnetic cooling technology

has historically been relegated to cryogenic,

high-magnetic field applications since efficiency

was so poor at higher temperatures. In 2004, we

made progress in identifying materials with greatly

improved performance close to room temperature.

For U.S. industry to take advantage of these new

materials, their behavior needs to be understood

and methods of proper measurement determined.

We are providing the metrology to do that.

Robert Shull, Virgil Provenzano, and

Alexander Shapiro

I

n 1997 a large (“giant”) magnetocaloric effect was

reported in the Gd5Ge2Si2 compound between 270 K

and 300 K, thereby generating a great deal of interest as

a potential near-room temperature magnetic refrigerant.

Unfortunately, large hysteretic losses occur in the same

temperature range where this compound exhibits its

large magnetocaloric effect, making the magnetic

refrigeration with the material inefficient.

In Nature [Vol. 429, p. 853 (2004)], we reported

on the discovery of an effective and straightforward

method for greatly reducing (by more than 90 percent)

the large hysteresis losses in Gd5Ge2Si2. This is

accomplished by alloying the compound with a small

amount of iron, which has the additional benefit of

shifting the magnetic entropy change (∆Sm) peak

to higher temperature, from 275 K to 305 K, and

broadening its width. Although the addition of Fe yields

comparable refrigerant capacity (RC) values, a greater

resultant value is obtained for the Fe-containing alloy

when the hysteresis losses are subtracted. The

Fe-containing alloy is clearly better for near-room

temperature magnetic refrigeration applications.

Figure 1 shows the magnetization (M) vs. applied

magnetic field (H) data measured in the important

temperature range of peak magnetocaloric effects

for the Gd5Ge2Si2 compound. In this material, the

enhanced values of the magnetocaloric effect have

been ascribed to the existence of a field-induced

crystallographic phase change in the material from

a low-field paramagnetic structure to a high-field

ferromagnetic crystal structure. As a consequence of

this field-induced phase change, there is hysteresis in

its transformation, shown by the shaded areas enclosed

within the field cycles, corresponding to the cost in

energy to make one cycle. The magnitude must be

assessed when determining whether a particular

refrigerant is useful in a given application.

Figure 2: Magnetic hysteresis measurements showing no

field-induced ferromagnetic transition and nearly zero hysteresis

in the Gd5Ge1.9Si2Fe0.1 alloy.

Figure 1: Magnetic hysteresis measurements showing a

field-induced ferromagnetic transition and large hysteresis in

the “giant magnetocaloric effect” Gd5Ge2Si2 compound.

We have found that by adding a small amount of

Fe to the Gd5Ge2Si2 compound, the hysteresis may

be significantly reduced. This effect is shown in the

M vs. H data for this alloy in the important temperature

range of potential use in Figure 2, where the shaded

hysteresis regions are nearly zero.
9

Technical Highlights

A magnetic field is alternately applied and removed

from a refrigerant during a single cooling cycle in a

magnetic refrigerator, thus any magnetic hysteresis

will reduce the usefulness of a material. Figure 3

shows exactly how much of a difference in hysteresis

there is between the Gd5Ge2Si2 and Gd5Ge1.9Si2Fe0.1

alloys.

The reduced hysteresis in the quaternary alloy is due

to a lack of field-induced paramagnetic-to-ferromagnetic

crystallographic phase change. This change in behavior

is caused by the Fe combining with primarily the Si in

the ternary compound to form an Fe-rich secondary

phase, thereby reducing the Si content in the majority

Gd-Ge-Si phase. As a consequence, the thermodynamics

of the Gd-Ge-Si alloy were changed from that of the

precursor Gd5Ge2Si2 compound.

The magnetic entropy change (∆Sm) for a 5 T

applied field as a function of temperature for both

alloys is shown in Figure 4. The computed refrigerant

capacities (RC) are indicated on the figures and shown

by the shaded areas. Compared to Gd5Ge2Si2, the

iron-containing compound exhibits a smaller, but

broader ∆Sm peak, and a ∆Sm peak at a higher

temperature. Purely on this basis, Gd5Ge2Si2 is the

superior material, but the Fe-containing alloy might be

attractive for higher temperature applications due to

its higher temperature peak.

One method to account for the hysteresis losses of

each alloy is to simply subtract it from the corresponding

refrigerant capacity value. Subtraction of the average

hysteresis in the temperature range of the ∆Sm peak

for each alloy (~ 65 J/kg and ~ 4 J/kg, respectively,

for the ternary and quaternary alloys) from the

corresponding refrigerant capacity values yielded

approximate values of 240 J/kg for the Fe-free alloy

and 355 J/kg for the Fe-containing alloy. Consequently,

when the hysteresis losses are taken into account,

it is clear that the Gd5Ge1.9Si2Fe0.1 alloy is a much

better magnetic refrigerant than the Gd5Ge2Si2

compound despite its lower ∆Sm peak value.

Most prior evaluations of magnetic refrigerants have

disregarded the material hysteresis losses, and in

some materials these losses can be quite large; this

example shows the weakness in that approach.

“The results are pretty amazing,” states Michael

DiPirro [Science News 165, 405 (2004)], a cryogenic

engineer at the NASA Goddard Space Flight Center

in Greenbelt, Maryland.

For More Information on this Topic

Virgil Provenzano, Robert D. Shull, and

Alexander J. Shapiro, “Reduction of hysteresis

losses in the magnetic refrigerant Gd5Ge2Si2 by

the addition of Iron,” Nature 429, 853 (2004).

Figure 3: Hysteresis energy loss as a function of temperature

for the Gd5Ge2Si2 and Gd5Ge1.9Si2Fe0.1 alloys.

Figure 4: Computed ∆Sm [for ∆H = 3980 kA/m (5 T)],

normalized with respect to sample mass, of the Gd5Ge2Si2

compound (top) and of the Gd5Ge1.9Si2Fe0.1 alloy (bottom),

plotted as a function of temperature showing the presence of

peaks centered near 270 K and 305 K respectively for Gd5Ge2Si2

and Gd5Ge1.9 Si2Fe0.1.
10

Technical Highlights

The magnetic data storage industry is seeking

to sustain the 30-year trend of exponentially

increasing storage density. This must be achieved

at the same time as maintaining the stability of the

recorded data. The Metallurgy Division at NIST

is collaborating with Seagate Technology to

develop the processes required to produce

patterned media of high-magnetic coercivity

that will meet this challenge.

Jonathan J. Mallett, Thomas P. Moffat, and

William F. Egelhoff, Jr.

Conventional magnetic data storage media are based

on granular films in which many fine grains are

used to define each magnetic bit. The minimum

number of grains per bit is limited by the irregularity

of the shape and spacing of the grains, which produces

irregular boundaries between bits. This irregularity

results in noise in the read signal and can only be

constrained at an acceptable level by maintaining a

fixed minimum number of grains per bit. The natural

approach to increasing data storage density has been

to reduce the grain size, while maintaining the same

number of grains per bit. The limit to this approach

occurs when the magnetic energy barrier to the reversal

of magnetization of each grain approaches the energy of

random thermal fluctuations. At this point, the medium

is no longer stable against spontaneous magnetization

reversal and consequential data loss.

The grain size at which this limit occurs depends

on the magnetocrystalline anisotropy energy of the

Grand Challenges in Nanomagnetics: High Coercivity FePt

Alloys for Future Perpendicular Magnetic Data Storage

magnetic material. FePt in its L10 phase has a

sufficiently large anisotropy energy to allow

magnetically stable grains of 5 nm diameter (Figure 1).

Furthermore, FePt deposited by a variety of means

typically forms grains approaching this size.

Unfortunately, the annealing treatment required to

transform the as-deposited A1-structured FePt to

the desirable L10 phase is widely found to result

in an increase in grain size to 100 nm. Current

efforts at NIST focus on developing a method of

electrochemically depositing FePt into a regular

patterned template, circumventing the problem of grain

growth. Simultaneously, the imposed regularity of the

magnetic cells opens the possibility of addressing single

cells (i.e., of using one “grain” per bit). The estimated

achievable density from such an approach is 7 Tbits

per square inch, which is 100 times higher than current

storage densities. Electrodeposition is an obvious

choice for deposition into high aspect ratio templates,

since it does not suffer from the shadowing effect

that characterizes vacuum deposition techniques.

Figure 2: The double cell, designed to minimize the concentration

of Fe3+ and dissolved O2 in the FePt plating solution.

Figure 1: The dependence of storage density on magnetocrystalline

anisotropy energy. The most promising materials are FePt

and CoPt.

Electrodeposition of FePt from aqueous solutions

presents many challenges. The double cell shown in

Figure 2 has been developed to address the problem of

the instability of Fe2+ solutions, which readily oxidize

to produce insoluble Fe(OH)3. The plating solution,

containing FeCl2 and PtCl4 (left) is separated from the

anode by a cation selective membrane, preventing the

oxidation of Fe2+ to Fe3+ that would otherwise occur

at the anode. Fe3+ formation by oxidation with air is

also minimized by blanketing the cell in nitrogen, and

residual Fe3+ is reduced to Fe2+ by an auxiliary

platinum grid electrode.
11

Technical Highlights

The alloy composition of 300 nm thick films

deposited from this solution was found to depend

mainly on the applied potential and to be insensitive

to the concentration of the solution components.

A thermodynamic regular solution model was used

to describe the dependence of film composition on

applied potential. The comparison of theory to

experimental data can be seen in Figure 3.

The deposited films were found to be remarkably

smooth, with RMS roughness values less than 5 nm

for micron-thick deposits. This was surprising given

the large platinum overpotential (supersaturation),

which usually results in growth instabilities and

consequent roughening.

The control of crystal orientation is an essential

consideration for high-density recording applications.

A transition in the recording industry is currently in

progress to perpendicular media, in which the bits are

magnetized perpendicular to the plane of the medium.

Maximum advantage can be derived from L10 FePt as a

perpendicular medium when it is correctly aligned with

its magnetic easy-axis perpendicular to the substrate

plane. A careful choice of substrate and annealing

parameters is required to recrystallize the as-deposited

random fcc alloy to appropriately oriented L10.

Figure 3: The theoretical and experimental dependence of

composition on the applied potential.

FePt electrodeposited onto a Cu (001) substrate

has recently shown great promise. X-ray diffraction

revealed the transition to L10 upon annealing, and X-ray

pole figures indicated favorable orientations. Figure 4

shows FePt L10 (001) and (110) pole figures. The

(001) figure indicates perpendicular orientation of the

magnetic easy-axis (the c-axis), while the (110) figure

indicates an in-plane texture. The in-plane texture is an

added advantage, as it results in a narrower switching

field distribution.

Copper additions to the alloy have been found to

lower the A1/L10 phase transition temperature by up

to 90 oC. It may be speculated that interdiffusion of

copper from the substrate during the anneal allowed the

recrystallization to proceed from the interface with the

substrate. It is likely that this would allow the film to

replicate the orientation of the substrate.

Figure 4: X-ray pole figures showing favorably oriented FePt L10 .

Figure 5: Magnetic hysteresis measurements showing a 10 kOe

coercivity.

 Magnetic hysteresis measurements performed

using a Kerr magnetometer are shown in Figure 5.

The magnetic coercivity of 10 kOe is comparable to

figures quoted in the literature for vacuum-deposited

FePt. It is believed to be the highest value reported

for an electrodeposited film.

Current efforts focus on controlling the

interdiffusion between substrate and film to minimize

loss of magnetization in the alloy, and on moving

from planar films to through-mask deposited arrays

of FePt pillars.

For More Information on this Topic

W.F. Egelhoff, Jr. (Metallurgy Division, NIST);

E.B. Svedberg (Seagate Research, Pittsburgh)
12

Technical Highlights

Conductors in on-chip metallizations are now

reaching dimensions so small that defective

seed layers are impacting manufacturing yields,

and electron scattering on surfaces and grain

boundaries is reducing electrical transport in

the buried wires. Our goal is to provide tools

to overcome these barriers. Recent efforts have

quantified sources of the increased resistivity in

wires made of silver, the most conductive of all

metals, demonstrated seedless processing routes

for copper wires, and improved understanding

and modeling of the superfill fabrication process.

Daniel Josell and Thomas P. Moffat

The steady reduction of transistor dimensions in

integrated circuits has been accompanied by similar

size reductions of the on-chip interconnects that carry

electrical signals, pushing the industrial technology for

copper seed deposition close to its limit for defect-free

sidewall coverage. Defects in seed layers, which

arise from limitations in existing sputter technology,

lead to voiding during electrodeposition of the

copper metallization.

Additionally, with the dimensions of the copper

wires in these metallizations now approaching the

intrinsic mean-free-path length of the conduction

electrons, scattering on the wire surfaces has begun

to significantly reduce electron transport and, thus,

the associated electrical conductance of the wires.

With grains in these conductors similarly sized, a

reduction is also to be expected from grain boundary

scattering. While the penalty for both effects is

increased power dissipation and reduced clock speed,

the appropriate approach for mitigation requires

quantitative determination of the relative sizes of

the contributions.

On-Chip Interconnects:

Extending Performance of Sub-100 nm Lines

Technical Details

A tri-layer titanium, palladium and silver seed

(Figure 1) was shown to yield smooth, conductive

surfaces for the electrodeposition of silver wires for

the electrical properties study. The poor seed coverage

that is visible toward the bottom of the smallest

trench (Figure 1c) is a technical challenge noted in the

International Technology Roadmap for Semiconductors.

Such seed defects motivated the “seedless” ruthenium

barrier-based process detailed in last year’s report and

continued by this year’s demonstration of seedless

copper superfill in trenches with ruthenium or iridium

barriers (Figure 2) deposited by perfectly conformal

atomic layer deposition (ALD).

Figure 1: Ti/Pd/Ag seed layer in sub-100 nm deep trenches.

Figure 2: Trenches containing copper that was electrodeposited

directly on an ALD iridium barrier (thin bright layer).

Figure 3: Cross-section views of silver wires fabricated by

electrodeposition in the seeded trenches followed by removal of the

metal from the field (transmission electron microscope).
13

Technical Highlights

Figure 4: Electrical resistivities of 300 nm tall silver wires

compared to predictions that account for surface scattering with

varying amounts of grain boundary scattering. Resistivities for

wires less than 100 nm wide are impacted by defects.

For the electrical studies, silver wires (Figure 3) were

fabricated by silver electrodeposition on the tri-layer seeds

(Figure 1), using a superfill process developed in the

Metallurgy Division, followed by removal of the metal

in the field adjacent to the wires through chemical–

mechanical planarization and ion polishing.

The wires were studied in a standard four-point probe

geometry that permitted measurement of wire resistances.

Resistivities, obtained from the resistances using measured

wire dimensions, increased significantly with decreasing

wire width (Figure 4). To assess the origin of the resistivity

increase, the Fuchs–Sondheimer analysis for diffuse

scattering of electrons on surfaces was extended to

permit analysis in the presence of both specular and

diffuse scattering. The resulting equations, along with

a previously published equation for grain boundary

scattering, permitted quantitative evaluation of the

experimental data. Significantly, modeling of the data

showed that the increase of resistivity with decrease

of wire size arises as much from scattering on grain

boundaries as from scattering on the wire surfaces.

This indicates that efforts to mitigate size effects must

increase grain size as well as surface specularity if

they expect to be more than modestly successful.

The continuing industrial need for predictive

simulation of feature filling spurred experiment and

modeling of the superfill process itself. Consumption

of adsorbed accelerator, a detrimental deviation from

the surface segregation behavior that is responsible for

the superfill process, was measured. Inclusion of such

consumption in our Curvature Enhanced Accelerator

Coverage (CEAC) model and computer code have made

the filling predictions even more accurate.

This research has continued to impact industry,

indicated by requests for our superfill code from Intel,

Applied Materials, ST Microelectronics, and ATMI;

an invited article on superfill in the IBM Journal of

Research and Development; and invited presentations

given at Cookson–Enthone, in addition to publications

and presentations at conferences.

Selected Project Publications

for FY2004

T.P. Moffat, D. Wheeler, M. Edelstein and D. Josell,

“Superconformal Film Growth: Mechanism and

Quantification,” IBM J. Res. and Dev., in press.

D. Josell, C. Burkhard, Y. Li, Y.-W. Cheng, R.R.

Keller, C.A. Witt, D. Kelley, J.E. Bonevich, B.C. Baker,

T.P. Moffat, “Electrical Properties of Superfilled

Sub-Micrometer Silver Metallizations,” J. Appl. Phys.

96 (1), 759–768, (2004).

D. Wheeler, T.P. Moffat, G.B. McFadden, S. Coriell

and D. Josell, “Influence of Catalytic Surfactant

on Roughness Evolution During Film Growth,”

J. Electrochem. Soc. 151 (8), C538–C544, (2004).

T.P. Moffat, D. Wheeler, and D. Josell,

“Electrodeposition of Copper in the SPS-PEG-Cl Additive

System: I. Kinetic Measurements: Influence of SPS,”

J. Electrochem. Soc. 151 (4), C262–C271, (2004).

W.J. Evans, D.G. Giarikos, D. Josell, and J.W. Ziller,

“Synthesis and Structure of Polymeric Networks of

Silver Hexafluoroacetylacetonate Complexes of THF,

Toluene, and Vinyltrimethylsilane,” Inorg. Chem. 42,

8255–8261, (2003).

For More Information on this Topic

D. Josell, T.P. Moffat (Metallurgy Division, NIST);

G. McFadden (Mathematical and Computational Sciences

Division, NIST); R.R. Keller, Y.-W. Cheng (Materials

Reliability Division, NIST); C. Witt (Cookson–Enthone);

C. Burkhard, Y. Li (Clarkson University); D. Wheeler

(University of Maryland); T.K. Aaltonen, M. Ritala,

M. Leskelä (University of Helsinki, Finland)

Figure 5: Simulations of superconformal feature filling now

account for consumption (incorporation) of adsorbed catalyst.
14

Technical Highlights

The Structural Steel of the World Trade Center Towers

Figure 1: Enhanced image of the impact zone has allowed

determination of failure modes in the perimeter columns.

An outline of the plane is superimposed. Steel panels recovered

for the investigation are highlighted in color.

Task 2 — Categorize Failure Mechanisms

Based on Visual Evidence

The damage to the steel components of the buildings

represents an important check on the accuracy of the fire

and impact modeling, with the caveat that the recovered

steel could have been damaged before the collapse,

during the collapse, or during the salvage efforts.

Image enhancement techniques were used to

study photographs of the impact zones of the towers

to establish the failure mechanisms of the perimeter

columns. By making montages of many different

images, it was possible to produce a nearly smoke-free,

composite view of the columns that the aircraft struck.

The columns failed by several different mechanisms.

One important result was the demonstration that several

key impact-zone columns in the NIST inventory were

damaged primarily in the aircraft impact, and not in the

subsequent collapse or recovery efforts. Figure 1 is a

map of the impact zone of WTC 1 that illustrates the

nature of the damage to the individual columns.

Tasks 3 & 4 — Determine Steel

Properties to Support Airplane Impact

and Structure Performance Studies;

Correlate Properties with Those

Specified in the Construction

One important part of this task was to assess the

quality of steel and determine whether it met the original

specifications. In support of this goal, the group conducted

more than 200 room-temperature tensile tests on samples

from 39 different building components, which represented

In August of 2002, NIST took responsibility for the

investigation of the World Trade Center disaster. The

investigation objectives include determining: why

the buildings collapsed; the procedures and practices

used in the design, construction, operation and

maintenance of the buildings; and areas in codes

and practices that warrant revision. The eight

interdependent projects include Project 3 — Analysis

of Structural Steel, led by the Materials Science and

Engineering Laboratory. The objective of the project

is to determine and analyze the properties and

quality of the steel, weldments, and connections

from steel recovered from the World Trade Center.

Stephen W. Banovic, Richard J. Fields,

Timothy J. Foecke, William E. Luecke,

J. David McColskey, Christopher N. McCowan,

Thomas A. Siewert, and Frank W. Gayle

I

n terms of the steel used, the World Trade Center

was very complex. Plans called for steels of fourteen

different yield strengths between 36 ksi and 100 ksi.

Many of these steels were proprietary and were not

supplied to any existing ASTM specification. To further

complicate matters, four different fabricators provided

steel for the upper stories, and each used steel from

more than one supplier. Most of the records that

documented the steel actually used were either not

preserved or destroyed in the collapse.

The MSEL Metallurgy and Materials Reliability

Divisions have determined properties of the steel

recovered from the WTC site and characterized failure

modes associated with pre-collapse damage. This

information has been provided for use in models of the

building response to airplane impact and fire. In 2004,

all major tasks were completed.

Task 1 — Collect and Catalog

Physical Evidence

The Structural Engineers Association of New York

(SEAoNY), later supplemented by NIST personnel, spent

countless hours selecting steel in the New Jersey recycling

yards for later forensic analysis. After shipment to NIST,

the Metallurgy Division cataloged the 236 recovered steel

components. Since many pieces were stamped and painted

with unique serial numbers correlated with the building

plans, it was often possible to identify the exact original

location in the building.

As a second part of this task, we also researched

contemporaneous construction documents and steel

specifications. This task helped identify steel suppliers

and fabricators, as well as material substitutions.
15

Technical Highlights

Figure 2: Yield strength — measured vs. specified minimum.

The few anomalous data can be attributed to damage incurred

in the collapse that removed the yield point behavior, or to the

natural and accepted strength variability of structural steel.

all the steels relevant to the investigation. Tests indicate

that the steels generally met or exceeded the specified

minimum strengths (Figure 2).

Steel specifications also regulate the chemical

compositions. More than 350 different specimens,

representing nearly every relevant steel component in

the building, were analyzed for chemical composition

and all of the sections relevant to the investigation. The

chemical analysis helped confirm archival information

that an American steel mill supplied steel for parts of

the perimeter columns. The analyses also support the

conclusion that the steels in the buildings met the

specifications called for in the building plans.

The strength of steel increases as the deformation

rate increases. Accurately modeling these rate effects

is essential for estimating the energy and momentum of

the aircraft remnants which damaged the core columns.

To establish the strain rate sensitivity of the relevant

steels, we have conducted more than 100 tests on

specimens from both the perimeter and core columns

at rates up to 2000 s–1 (200,000 % deformation

per second).

Ultimately, the fires in the towers weakened the steel

structure leading to collapse. We conducted more than

100 high-temperature tensile and creep tests to provide

models of the deformation of structural steel at elevated

temperatures for use in models of the building response

to the fires.

Task 5 — Analyze Steel to

Estimate Temperature

Just as the nature of the deformation and failure

of the recovered steel reveals information about the

impact and collapse, the steel can also contain evidence

of its exposure to the elevated temperatures in the fire.

The situation is made more complex because much

of the steel was also exposed to extended fires in

the rubble before recovery. Several different methods,

both conventional and novel, were examined for

estimating high-temperature excursions seen by the

steel. Only one method proved to be robust and easy

to implement: paint on steels that reached temperatures

over 250 °C cracked from the difference in thermal

expansion between the paint and the steel.

Figure 3: Illustration of the method to establish the temperature

excursions of recovered steel. The segment of the column

protected by the floor slab remained at lower temperature.

From photographs showing fire in windows, all

recovered columns that may have been exposed to

pre-collapse fire were identified and characterized

using the paint crack technique. Figure 3 illustrates

one of the columns that showed evidence of having

exceeded 250 °C.

Outputs

Outputs for the project include parts of the

June 2004 Progress Report on the World Trade Center

Disaster (NIST SP 1000-5) and numerous memos for

contractors that explain how to employ Project 3 data

and deformation models. The final NIST investigation

report will be released in the spring of 2005.

For More Information on this Topic

T.A. Siewert (Materials Reliability Division, NIST);

F.W. Gayle (Metallurgy Division, NIST)
16

Program Overview

The competitiveness of U.S. manufacturers

depends on their ability to create new product concepts

and to speed the translation from concept to market

while decreasing product cost. This is equally true

for well-established “commodity” industries, such

as automotive and aerospace, and rapidly growing

or emerging industries, such as biotechnology and

nanotechnology. For existing products, manufacturing

is a critical step in reducing product cycle time. Rapid,

low-cost development of manufacturing processes is

needed to incorporate new materials into complex

product shapes with higher performance at equivalent

or lower cost as the competing, established materials

and methods. For innovative product concepts, new

materials with increasing functionality are needed to

translate these concepts to reality.

To realize such improvements in materials and

manufacturing, MSEL is developing robust measurement

methods, models, standards, and materials and process

data needed for design, monitoring, and control of

manufacturing processes. A growing challenge is being

able to design, monitor, and control such materials and

manufacturing processes at size scales from nanometers

to meters. The Advanced Manufacturing Processes

Program focuses on the following high-impact areas:

■ Combinatorial, high-throughput methods for materials

ranging from thin films and nanocomposites to

micro- and macroscale material structures;

■ Industry-targeted R&D centered on unique

measurement facilities in forming of lightweight

metals for automotive applications, polymer

processing, and high-speed machining;

■ Innovative testbeds for emerging materials,

including carbon nanotubes and fuel cells;

■ National traceable standards having a major impact

on trade, such as hardness standards for metals

and process standards for polymers; and

■ Innovative, physics-based process modeling tools.

Our research is often conducted in close

collaboration with industrial consortia and standards

organizations. These collaborations not only ensure

the relevance of our research, but also promote rapid

transfer of our research to industry for implementation.

Three projects focused on Advanced Manufacturing

Processes are highlighted below.

NIST Combinatorial Methods Center (NCMC)

The NCMC develops novel high-throughput

measurement techniques and combinatorial experimental

strategies specifically geared towards materials research.

Advanced Manufacturing Processes

These tools enable rapid acquisition and analysis of

physical and chemical data, thereby accelerating the

pace of materials discovery and knowledge generation.

By providing measurement infrastructure, standards, and

protocols, and expanding existing capabilities relevant

to combinatorial approaches, the NCMC lowers barriers

to the widespread industrial implementation of this new

R&D paradigm. MSEL uses a two-pronged strategy for

accelerating the development and implementation of these

approaches: an active intramural R&D program that

demonstrates the ability of combinatorial methods to

produce cutting-edge scientific research and an ambitious

outreach activity; key to this effort is the validation of

these approaches with respect to traditional “one at a time”

experimental strategies.

Forming of Lightweight Metals

Automobile manufacturing is a materials intensive

industry that involves about 10 % of the U.S. workforce.

In spite of the use of the most advanced, cost-effective

technologies, this globally competitive industry has major

productivity issues related to measurement science and

data. Chief among these is the difficulty of designing

stamping dies for sheet metal forming. An ATP-sponsored

workshop (“The Road Ahead,” June 20–22, 2000) identified

production of working die sets as the main obstacle to

reducing the time between accepting a new design and

actual production of parts. This is also the largest single

cost (besides labor) in car production. To benefit from

weight savings enabled by new high-strength steels

and aluminum alloys, a whole new level of formability

measurement methods, models, and data is needed,

together with a better understanding of the physics

behind metal deformation. MSEL is working with

U.S. automakers and their suppliers to fill this need.

Polymer Processing

Polymers have become ubiquitous in the modern

economy because of their processability, high functionality,

and low cost. However, these materials can exhibit

complex and sometimes catastrophic responses to the

forces imposed during manufacturing, thereby limiting

processing rates and the ability to predict ultimate

properties. The focus of our polymer research is on

microfluidics and microscale processing, modeling of

processing instabilities, and on-line process monitoring

of polymers. Our unique extrusion visualization facility

combines in-line microscopy and light scattering for the

study of polymer blends, extrusion instabilities, and the

action of additives. These measurements are carried out

in close collaboration with interested industrial partners.

Contact: Carol A. Handwerker (Metallurgy Division)
17

Advanced Manufacturing Processes

Increased computing power coupled with finite

element modeling methods (FEM) has brought

springback-compensated die design within

reach of the automotive industry. In developing

this technology, industry has determined that

better measurement methods and an improved

understanding of the influence of large plastic

strains on the properties and behavior of materials

during springback is required. This project seeks

to develop the understanding, measurements,

and data to meet this need.

Richard E. Ricker

AU.S. Council for Automotive Research (USCAR)

 Consortium on Springback Prediction has

developed finite element springback prediction models

to reduce die design and tryout costs. However,

these models consistently underpredict springback.

Three alloy properties could vary with plastic strain

and contribute to prediction errors: (1) elastic modulus,

(2) anelastic modulus, and (3) strain-dependent

anelastic behavior (reverse creep or plastic hysteresis).

Currently, FEM modelers compensate for these

errors with arbitrary constants estimated from trials

or prior experience. The objectives of this study are to

determine the origin of these errors, evaluate relevant

measurement methods, and provide materials data

that improves FEM springback prediction codes.

In FY 2003, we demonstrated that the large biaxial

strains typical of forming can significantly reduce the

elastic modulus of Al alloys (18 %) and that texture

changes cannot explain this behavior. In FY 2004,

finite element models were used to analyze the results

of NIST 3-point bend springback measurements.

Combining these results with modulus data obtained in

FY 2003, it was determined that the strain and elastic

modulus variations are too small to measure in these

experiments. During FY 2004 these results were

presented at industry workshops (USCAR Consortium,

Deep Drawing Research Group) and at metallurgy and

physics conferences (ASM, TMS, APS).

Also in FY 2004, Mg and Mg alloys were studied

to determine how widespread this anomalous modulus

behavior is and to gain additional clues as to its origin.

Mg is an extremely lightweight HCP metal that would

be a prime candidate for automotive applications if

not for its poor formability and high chemical reactivity.

Biaxial strain experiments did not produce a significant

change in the elastic modulus, but the limited ductility

prevented measurements at the high strains required to

unambiguously reduce the modulus in Al alloys. Dynamic

modulus analysis (DMA) found that plastic strain produced

a broad peak in the imaginary component of the complex

modulus. Previous researchers attributed this peak to

grain boundary sliding, but plastic strain and twinning were

found to be responsible for this peak which analysis

indicated contains 4 subpeaks (Figure 1).

Sheet Metal Forming for Automotive Applications:

Anelasticity and Springback Prediction

In a separate study, niobium is a BCC metal that

DOE’s Jefferson Laboratory (JL) uses to fabricate

superconducting structures by stamping and forming

operations similar to those used by the automotive

industry to form BCC steel. The Jefferson Laboratory

has funded NIST to investigate the catastrophic effect

of impurities on the forming behavior of high purity Nb.

DMA experiments detected variations in the interstitial

impurity content of this high purity metal (Figure 2),

which will now be correlated with forming behavior.

Contributors and Collaborators

S.W. Banovic, R.J. Fields, L. Ma, D.J. Pitchure

(Metallurgy Division, NIST); D. Dayan, A. Munitz

(NRC-Negev); V. Luzin (NCNR); G. Myneni (JL);

E. Chu (Alcoa); USCAR Springback Consortium

Figure 1: DMA peak in deformed Mg alloy AZ31. (Alcoa, DaimlerChrysler, Ford, GM, LSTC, U.S. Steel)

Figure 2: DMA peaks from two lots of Nb compared to the

calculated locations for O, C, and N.
18

Other topics explored during this fiscal year include:

1) statistical analyses of surface roughness data aimed

at determining what roughness measures would be most

useful for industry; 2) EBSD/SLCM studies of AlMg

binary alloys as a function of strain; and 3) exploratory

work on new methods for measuring friction under

conditions designed to emulate actual forming operations.

Contributors and Collaborators

J. Liu, T. Foecke, R.E. Ricker, L.E. Levine (Metallurgy

Division, NIST); M.D. Vaudin (Ceramics Division, NIST);

T. Gnäupel–Herold, (NIST Center for Neutron Research);

J.B. Hubbard (CSTL, NIST); R. Reno, E. Moore (UMBC)

Advanced Manufacturing Processes

The existing data, measurement methods, and

basic understanding of metallurgical factors that

influence friction, tearing, and surface finish

during sheet metal fabrication are insufficient to

meet the predictive modeling requirements of the

automotive industry. This project addresses these

needs by exploring the microstructural origins

of the distribution of slip, surface roughening,

and strain localization during plastic straining.

The primary focus of these investigations is

the relationships between the initial material

characteristics and the deformation behavior

of Al and Fe base sheet materials.

Mark R. Stoudt and Stephen W. Banovic

Replacement of conventional steel sheet by aluminum

alloys and high-strength low-alloy steels would

significantly reduce automobile weight and increase fuel

efficiency. However, wide spread application of these

materials by the automotive industry is limited primarily

due to formability issues and deficiencies in material

databases/constitutive laws affecting finite element

modeling. This project examines the underlying structure

property relationships associated with formability in an

attempt to improve the numerical simulations that predict

deformation behavior of materials.

Microstructural Origins of Surface Roughening

and Strain Localizations

In FY 2004, several experimental techniques were

used together to explore the relationships between strain,

local crystallographic texture and surface roughening of

aluminum alloys. Figure 1a is an electron backscattered

diffraction (EBSD) map showing the variations in surface

grain orientation on a 6xxx series aluminum sample after

applying a uniaxial strain of 0.08. As reflected in the figure

inset, the surfaces of grains 1, 2 and 3 have <001>, <101>

and <111> orientations, respectively. A 3D topograph

of the same region obtained with a scanning laser confocal

microscope (SLCM) is shown directly below Figure 1a

in Figure 1b. The labels indicate the same grains in

both figures. There are clear differences in the slip band

structures of the grains. The roughness profiles shown

in Figure 2 were acquired from the SLCM data along the

white lines in Figure 1b. The different crystallographic

orientations in the three grains produced distinctly different

roughness characters for the same level of macroscopic

uniaxial strain. New statistical analysis techniques are

currently being developed to investigate correlations

in these data.

Figure 1: Surface Characterization of 6xxx series aluminum

deformed to 0.08 uniaxial strain. a) EBSD generated grain

orientation map; b) SLCM surface topograph of same region.

Figure 2: Roughness profiles obtained from the three individual

grain orientations shown in Figure 1.
19

Advanced Manufacturing Processes

Predicting the final shape of a part produced

using a complex fabrication process can be

extremely challenging. This is particularly true

when microstructure and residual stresses play

significant roles. Understanding the interplay of

these factors in industrially important test cases is

the goal of this project. Work on this project was

completed this fiscal year.

Lyle E. Levine and Hank Prask (856)

Diffraction provides a powerful means of very

accurately measuring both microstructure and

mechanical behavior in a way that provides insight

simultaneously into both, and offers particular

opportunities for understanding plasticity. This project

collaborated with the developers of the NIST Object

Oriented Finite Element (OOF) program to implement

a plasticity model into OOF and devise critical

experimental and computational benchmarks to validate

OOF using the NCNR neutron diffractometer to

measure residual stress, texture and elastic properties.

Conventional X-ray sources were also used where

stress states measured at or near surfaces were

important for understanding the behavior of materials

or to compare with predictions. Synchrotron X-rays

were used to deal with subsurface residual stresses

in the thin, highly textured samples that result from

simulated forming operations. Specifically, the

following tasks were part of this project:

■ Experimentally validate calculation of the important

role played by residual stresses on high-precision

machining and forming operations (includes

collaborative contributions from MEL, ALCOA and

Boeing Corporation);

■ Provide technical assistance and validation testing

to CTCMS staff engaged in adding 3D plasticity

to OOF;

■ Develop the ability to characterize near-surface

residual stresses; and

■ Further develop neutron and synchrotron radiation

sources to provide high-resolution data needed to

relate microstructure, residual stresses, and their

effect on springback.

Overall Project Accomplishments

■ Validation of Distortion Prediction Method: In

2002, we validated residual stress measurement and

prediction methods used by industry. In 2003 and

2004, we used the NCNR to measure residual stress

distributions within 7000 series aluminum bars and

used high-speed machining to produce test parts.

The shapes of the final parts were measured using a

contact measuring machine and ALCOA will compare

these shapes to their model predictions.

■ Test of OOF: In FY 2003, textured polycrystalline

samples were tested for elastic modulus dependence

on texture. These results were compared with

predictions using Electron Backscatter Diffraction

and OOF.

■ Measurement of residual stresses in standard

springback cups in FY 2002: Measurements were

provided for the project on Standard Tests and Data

for Sheet Metal Formability. In addition, analyses

were done to understand the origin of these stresses.

■ Incorporation of plasticity: Project personnel

worked with CTCMS staff to provide algorithms

and techniques for incorporating plasticity into OOF.

Although this project is ending this fiscal year,

outgrowths of the work on residual stress

measurements of deformed sheet metal and plasticity

modeling for OOF continue in other projects.

Contributors and Collaborators

R. Fields, R. deWit (Metallurgy Division, NIST);

T. Gnäupel–Herold, V. Luzin (NIST Center for Neutron

Research); R. Ivester, R. Polvani (Manufacturing

Metrology Division, NIST); D. Bowden (Boeing);

E. Chu (ALCOA); R. Reno (University of Maryland)

Figure 1: Aluminum parts machined to test shape changes

caused by relaxation of residual stresses.

Plasticity, Fabrication Processes, and Performance
20

To meet the PNGV goals for fuel efficiency, the

U.S. automotive industry is moving to lighter,

high-strength materials for auto bodies. NIST

has surveyed industry and found that providing

designers with accurate material properties, and

methods to incorporate them into finite element

models of sheet metal forming dies, is a critical

need for the US auto industry. This project seeks

to develop new standard tests and metrology to

accurately determine sheet metal mechanical

response under forming conditions.

Tim Foecke and Mark Iadicola

For the U.S. automotive industry to transition to

new materials for formed sheet metal parts, they

must be able to mechanically characterize the starting

materials under realistic forming conditions, and input

this information into die design models. The Metallurgy

Division is conducting research to develop two sheet

metal formability tests, along with associated metrology,

that can be standardized and used by industry.

Springback is the elastic shape change to a part

associated with the residual stresses that develop during

the stamping process. This shape change complicates

assembly and accurate fit-up; thus, the automotive

industry has a strong desire to be able to either avoid it,

or at least be able to predict its magnitude and design

dies to account for it. The proposed test for springback

consists of splitting open a ring cut from the sidewall

of a deep drawn cup.

This year, the springback cup test was introduced

to ASTM at its national meeting in Florida, leading to

industry’s proposal to form a new ASTM committee

to explore standardization of this test. A crucial step

in this process has been taken by identifying several

industrial partners that are willing to participate.

Additional participants from both the producer and

end-user sides of the sheet metal industry are now

being sought for this new committee. The initial

robustness data set generated at NIST last year

forms a solid basis for the design of a round-robin

testing matrix to be implemented as part of the

standardization process.

Last year, an x-ray stress measuring system was

installed on the sheet metal formability station. This

unique instrumentation allows for the direct, in situ

measurement of the stress in a given direction while

the sample is under multiaxial load. This year we made

significant progress in mapping the multiaxial stress–strain

surface for three aluminum sheet alloys of interest to the

automotive industry: 5182, 6111 and 6022. Typical data

is shown in the Figure 1, where for the first time the

biaxial hardening exponent has been measured. In addition,

both the flow stress and the hardening exponent, n, were

found to differ in the transverse and rolling directions of

the sheet. These data will be used by industry to eliminate

several assumptions in place that extrapolate estimated

biaxial flow behavior based on a series of uniaxial tensile

tests. This should lead to more accurate designs and

cost savings.

This year, NIST was asked to generate materials

property data for simulations of prototype parts as part of

the NUMISHEET 2005 conference. In addition, taking

advantage of our unique capabilities to measure stress in

a forming part, another layer of complexity of the prototype

part simulation will require reproducing the measured

stresses at points of the part under the forming load.

Plans for FY 2005 involve completing measurement

of the multiaxial stress–strain surfaces for the three

above-mentioned aluminum alloys, as well as for a

series of steel alloys. This new project, in collaboration

with modelers at GM, will involve studying how the

flow surface evolves with different types and amounts

of multiaxial prestrain.

Contributors and Collaborators

T. Gnäupel–Herold (NIST Center for Neutron

Research); M. Shi (USS); E. Chu (ALCOA); C. Xia

(Ford); T. Stoughton, M. Wenner, C.T. Wang (GM);

A. Andersson (Volvo); E. Schedin (Avestapolarit)

Standard Tests and Data for Sheet Metal Formability

Figure 1: Balanced biaxial flow stress for 5182 Al alloy in

transverse (TD) and rolling (LD) directions.

Advanced Manufacturing Processes
21

The NIST Center for Theoretical and

Computational Materials Science was founded

in 1994 in order to fulfill its three-fold mission:

to investigate important problems in materials

theory and modeling with novel computational

approaches; to create opportunities for

collaboration where CTCMS can make a positive

difference by virtue of its structure, focus, and

people; and to develop powerful new tools for

materials theory and modeling and accelerate

their integration into industrial research. The

CTCMS supports numerous materials theory and

modeling projects both within and externally to the

Materials Science and Engineering Laboratory.

James A. Warren and Benjamin P. Burton

The NIST Center for Theoretical and Computational

Materials Science (CTCMS) is a research program

addressing industry needs for theory and modeling tools

for materials design and processing. The CTCMS is a

center of expertise in computational materials research

that develops tools and techniques and fosters

collaborations.

CTCMS integrates ongoing research at various

institutions by forming temporary multidisciplinary and

multi-institutional research teams as required to attack

key materials issues of national importance. The

CTCMS has three principal activities, all operating

interactively: planning, research, and technology

transfer. Workshops are held as the first step in

defining technical research areas with significant

technological impact, identifying team members, and

building the infrastructure for collaborative research.

The CTCMS provides infrastructure and support for

its members, including an interactive World Wide Web

server (www.ctcms.nist.gov) and modern computing

and workshop facilities.

Current research areas include theory and simulation

of a wide range of materials behavior, including phase

transformation kinetics and morphology, micromagnetics,

composite materials, foams, microstructure and

dynamics of disordered and partially ordered materials,

complex fluids, materials reliability, reactive wetting,

pattern formation, crystal growth, sintering, phase

transitions in biological systems, and solidification.

Current CTCMS working groups include the following:

■ High-Throughput Analysis of Multicomponent

Multiphase Diffusion Data.

The NIST Center for Theoretical and Computational

Materials Science

Advanced Manufacturing Processes

■ Phase Field Modeling Tools: The phase field

method has become one of the most flexible and

powerful methods for predicting the evolution of

materials microstructure. This effort focuses

on the development of both new applications for

this method and tools enabling the solution of the

complex equations which emerge from these models.

■ Effective Hamiltonian Methods: Use of fundamental,

quantum-mechanical descriptions to derive the

properties of matter is the ultimate goal of materials

modeling. This effort uses electronic structure

calculations to derive the phase stability of alloys.

■ WWW Tools for Scientific Collaboration: CTCMS

is working with information science specialists to

develop web-based tools for scientific collaboration.

■ Tools for Neutron Scattering Measurements:

While neutron scattering has become a critical tool

for the probing of material structure and properties,

interpretation of the results of experiments presents

a host of challenges for the scientist. This effort

attempts to develop a better theoretical framework

for the interpretation of such experiments.

■ Object-oriented finite element modeling of composite

materials: This team of researchers is developing a

set of object-oriented finite element modeling tools to

improve the characterization and property prediction

of composite materials. Public domain software tools

are available at www.ctcms.nist.gov.

The CTCMS also hosts web pages with resources and

tools in the following areas: an interactive, electronic

library of Green’s function and boundary element solution;

accurate, standardized micromagnetics modeling tools;

software tools to improve electronic packaging processes;

and a tool to compute equilibrium crystal shapes.

More detail can be found at www.ctcms.nist.gov.

Mechanisms for Collaboration with CTCMS

The CTCMS facilitates numerous interactions between

industry, academia, NIST, and other government and

national labs to apply materials theory and modeling to

solve U.S. industrial problems in materials design and

processing. Researchers interested in joining existing

efforts or starting new ones are encouraged to contact

the CTCMS. The CTCMS participates in the National

Research Council postdoctoral fellowship program and

hosts short-term and long-term visitors.
22

A substantial increase in the use of aluminum

alloys and high-strength steels in automobiles

would greatly increase fuel efficiency. The primary

reason why this has not yet occurred is a lack of

accurate deformation models for use in designing

the stamping dies. This project is developing a

physically based model of plastic deformation

using a combination of statistical physics

approaches, atomistic modeling and advanced

measurement techniques.

Lyle E. Levine

Plastic deformation of metals (as in cold rolling,

stamping, drawing, and metal fatigue) is of great

importance to industries worldwide, and improvements

in the basic technology would have a significant

effect on the U.S. economy. Unfortunately, existing

constitutive equations cannot accurately predict the

material behavior, and many tryout and redesign steps

are required. Another related difficulty is in the design

of new alloys with improved formability characteristics.

Currently, alloy design is done empirically with little

understanding of how the various constituents affect

the mechanical properties.

Addressing both of these issues, this project is

focused on developing constitutive laws based upon

the underlying physical processes that produce the

observed mechanical behaviors in metal alloys. Such

constitutive laws are inherently multi-scale since they

must describe phenomena on length scales ranging

from the atomistic all the way to the macroscopic

stress–strain behavior of bulk material.

Since the underlying processes are extremely complex,

most of our theory, modeling and experimental efforts

over the past several years were concentrated on

single-crystal pure Al as a model system. This work

culminated in the development of the segment length

distribution (SLD) model, that describes how macroscopic

deformation arises from the statistical behavior of large

numbers of dislocations. The model correctly predicts

the flow stress (Figure 1), the linear behavior of stage II

hardening, the non-linear hardening in stage III and the

development of slip lines and slip bands. The statistical

variables, <nL> and N0, represent the density of primary

dislocations and pinning points, respectively, in the sample.

Alloying the Al changes the mechanical properties by

affecting these statistical variables. Thus, this critical

surface is a universal surface for all Al alloys. The next

step is to connect the evolution of the statistical variables

to the underlying physics for Al alloys using atomistic

simulations that accurately incorporate the effects of

alloy chemistry.

Quantum-mechanics based (ab initio) modeling is

required to adequately describe the effects of chemistry

in atomistic simulations. Unfortunately, such simulations

are extremely CPU intensive and thereby limited to a

few hundred atoms. Atomistic modeling using classical

potentials can handle much larger systems but fails

for large bond distortions and chemistry effects.

A ground-breaking approach for directly coupling the

two methods has been developed that allows the use of

large-scale atomistic simulations with simple classical

potentials while limiting the more accurate ab initio

approaches to critical regions. Preliminary calculations

of vacancy energies near dislocations are now underway.

Washington State University (WSU) is conducting

experimental validation tests of the SLD model using

chemi- and photo-emission techniques to study the

time dependence of new surface production during

deformation. NIST researchers designed the UHV

tensile stage and single-crystal growth facilities, and

WSU paid for the fabrication with funding from DOE.

Finally, NIST researchers are supporting the

development of supporting science by serving on the

executive committee of the international conference

“Dislocations 2004” and coorganizing symposia at the

Fall 2004 MRS meeting and at “Plasticity 2005.”

Contributors and Collaborators

D. Pitchure, F. Tavazza (Metallurgy Division, NIST);

A. Chaka (Physical & Chemical Properties Division,

NIST); T. Dickinson, S. Langford, M. Cai (WSU)

Underlying Processes of Plastic Deformation in Metal Alloys

Figure 1: Universal flow surface (critical surface) for Al alloys

at ≈ 15 % strain.

Advanced Manufacturing Processes
23

U.S. industry annually spends $200 billion on

the machining of metal parts, and potential

cost savings are a driver towards high-speed

machining. Traditional knowledge-based

approaches have not been effective in improving

the efficiency of this rapidly developing field:

One recent study showed that industry chose

the correct machining parameters less than half

of the time. Through this project, NIST will

provide measurement capabilities, materials

data, and assessment of constitutive laws and

deformation models, which will provide users with

a capability of producing a first part correct.

Carelyn E. Campbell

To improve the efficiency of high-speed machining

and tooling, industry has employed finite element

modeling (FEM) to predict correct tooling and

machining parameters. However, FEM has had limited

success as much of the needed material property data

for high speed machining processes, which involve

large strains (>>1), high-strain rates (up to 106 s–1),

and high-heating rates (greater than 105 oC/s), is

insufficient. This project emphasizes two complementary

areas: (1) the development of fundamental data on

dynamic material behavior at high strain and heating

rates and the assessment of the constitutive laws

used to model this behavior; (2) the modeling and

characterization of the microstructural changes that

occur during the rapid deformation and rapid heating

in real machining operations. Residual stresses,

responsible for part distortion after machining, are being

measured at the NIST Center for Neutron Research.

The first research effort is focused on obtaining

the materials data and assessing whether currently

used constitutive laws are appropriate. A dynamic

material testing facility using a pulse-heated Kolsky

bar has been developed at NIST and is being used to

measure dynamic stress–strain data at high-strain rates

(approximately 500 s–1 to 105 s–1) with heating rates

ranging from 103 Ks–1 to 1 Ks–1. Measurements

on 1045 steel showed significant differences in the

stress–strain behavior depending on the heating and

strain rates (Figure 1). The two microstructures

shown in Figure 1 demonstrate the observed

microstructural differences resulting from different

heating rates. Test 504 was rapidly heated and

quenched, leaving no time for the pearlite to dissolve

and reform. In contrast, test 509 was heated, held at

temperature for 1.4 s, then quenched, leaving enough

time for the pearlite to dissolve and then re-crystallize

during quenching, producing a finer grain size.

These results demonstrated that the non-time dependent

constitutive relationships used by industry to describe

the stress–strain data for machining simulations are not

correct. A time-dependence must be included in the

constitutive relationship to correctly model the material

behavior during high-speed machining. Using the dynamic

material property data collected using the pulse-heated

Kolsky bar, time-dependent constitutive laws will be

developed and then tested in machining simulations.

High Speed Machining

Figure 1: The effect of various heating and strain rates on both

the stress–strain behavior and the microstructure of 1045 steel.

The second area of research focuses on

characterizing and modeling microstructural changes in

the deformation/hot zone of aluminum alloys during

machining. Transmission electron microscopy (TEM)

correlated with optical microscopy of the chip has

revealed bands of re-crystallized grains. The work

surface is being characterized using microhardness

measurements, TEM, optical microscopy and residual

stress measurements. A model based on these

microstructural characterizations and temperature vs.

time data from thermal images will be used as input to a

microstructure model. The microstructure model,

along with the time-dependent constitutive relationship,

will be implemented into a finite element code for

machining simulation.

Contributors and Collaborators

D. Basak, L. Levine, R. Fields, R. deWit, W. Boettinger,

L. Bendersky, T. Gnäupel–Herold, H. Prask (NIST/MSEL);

R. Ivester, R. Rhorer, K. Jurrens, J. Soons, R. Polvani,

E. Whitenton, M. Kennedy, B. Dutterer, G. Blessing

(Manufacturing Engineering Laboratory, NIST); T. Burns

(Information Technology Laboratory, NIST); H. Yoon

(PL); M. Davies (U. North Carolina–Charlotte)

Advanced Manufacturing Processes
24

The availability of reliable materials data is the

key to successful design of new materials and

manufacturing processes. Many commercial

processes are controlled by the thermodynamic

and diffusion properties of the material.

Thermodynamic and diffusion mobility databases

provide an efficient method of storing the wealth

of these data, and software tools allow the user

to efficiently retrieve the needed information.

Ursula R. Kattner and Carelyn E. Campbell

The complexity of traditional thermodynamics and

diffusion kinetics prevented their direct application

to the design of complex materials and processes in

the past. By the same token, graphical representation

of multicomponent systems is too complex, and storage

of every single datum is inefficient due to the enormous

amount of data. However, mathematical functions that

represent thermodynamic and diffusion properties of

the phases permit efficient storage. Since these functions

are based on physical models, they further provide the

power of extrapolation of binary and ternary systems to

higher order systems. Software then allows calculation

of the desired quantities. This approach is called the

CALPHAD methodology. Unfortunately, previous

software was tailored to be efficient for expert users and

was difficult for the occasional, less-experienced user.

The databases and software developed in this

project are designed to provide users with simple tools

to retrieve and disseminate information needed for

efficient materials and process design.

Mechanisms for Delivery of Thermodynamic and Kinetic Data

Figure 1: Graphical user interface for solidification calculations.

A modern, user-friendly front end for user input has

been developed for solidification calculations (Figure 1).

The results of the calculation are delivered to the user

in graphical as well as in tabular form. This program

is bundled with the NIST superalloy and solder

thermodynamic databases, but has the capability to

work with user-supplied databases as well. Results can

be used with a Mathematica script for DTA analysis

simulation. The software, databases and scripts are

available on the Metallurgy Division website

(www.metallurgy.nist.gov).

Figure 2: Schematic of an optimization scheme to allow direct

input of diffusion couple composition profiles.

Multicomponent, multiphase diffusion couples can

be simulated using NIST thermodynamic and diffusion

mobility databases, and experimental and calculated

composition profiles can be compared. However,

the complexity of such couples prevents experimental

diffusion coefficients from being easily extracted.

Current work focuses on methods to allow experimental

composition profiles to be directly inputted into a data

assessment process, so the composition profiles can

be directly related to the diffusion mobility parameters

stored in the database (Figure 2).

Interactions developed through the “High Throughput

Analysis of Multicomponent Multiphase Diffusion”

workshop series have led to several software codes aimed

to improve the analysis of multicomponent diffusion

couples based on combinatorial libraries. These codes

and other resources are listed on the group’s website

(www.ctcms.nist.gov).

Work continues to convert the NIST Diffusion Data

Center into an electronic searchable form. A preliminary

version should be available by December 2004.

Contributors and Collaborators

W.J. Boettinger (Metallurgy Division, NIST);

A.R. Roosen (Center for Theoretical and Computational

Materials Science, NIST); J.-C. Zhao (General

Electric); L. Höglund (Thermo-Calc AB)

Advanced Manufacturing Processes
25

Many properties of structural and functional

materials depend on the distribution of composition,

phases, grain orientations, internal surface stresses,

and microstructure. These structures span length

scales from nanometers to meters. Predictive

models are needed to reduce the enormous costs

and development times involved in designing and

inserting new materials into products. Phase field

models of solidification, coupled to stress, grain

orientation, and solute and vacancy dynamics are

being developed to address these needs.

James A. Warren

Modeling of microstructures produced by solidification, grain evolution, and stress, as well as other

processes, involves mathematical solution of equations

for heat flow, fluid flow, current flow and/or solute

diffusion. Boundary conditions on external surfaces reflect

the macroscopic processing conditions, while boundary

conditions at internal interfaces correspond to the liquid

crystal (grain) or grain–grain interfaces. These internal

interfaces are moving boundaries and require boundary

conditions with thermodynamic and kinetic character.

To deal with the complex interfacial shapes that develop

during solidification, grain growth, and the application of

external stress or pressures, the phase field method has

become the technique of choice for computational materials

scientists. This approach often requires numerical

techniques to solve the model equations but readily deals

with complex interface shapes and topological changes.

The research, conducted in collaboration with the Polymers

Division, is also supported by the NIST Center for

Theoretical and Computational Materials Science.

This year, significant advances were made in the

understanding of the formation of multi-grained

(polycrystalline) materials. Polycrystals often arise by

either the impingement and growth of grains nucleated in

a liquid (equiaxed grains), or via the nucleation of columnar

grains on a surface. In collaboration with researchers

in Japan and Hungary, we developed a phase field model

to study such growth. In a surprising development, this

same model has now elucidated a third mechanism of

polycrystalline growth: growth front nucleation. This

mode of growth is manifested when new orientations

nucleate on the front of a growing crystal, yielding a

densely branched morphology in which the structural

symmetries that arise due to effects of surface energy

anisotropy are disrupted by the nucleation process, yielding

an isotropic pattern. This model demonstrated that this

type of growth can be initiated by either static or dynamic

heterogeneities in the solidifying system, solving a riddle

that has been of substantial interest to materials scientists.

This work, published in Nature Materials, has attracted

extensive academic and industrial interest.

Phase Field Modeling of Materials Systems:

Simulation of Polycrystalline Growth

Figure 1: Two simulations of seaweed-like growth of an alloy.

The left column shows the solute profile while the right column

shows grain orientation. The upper row is a single crystal while

the lower is polycrystalline. Using such techniques, the potential

for polycrystalline growth to disrupt the influence of surface

energy anisotropy (which gives dendritic growth) is demonstrated.

Although a remarkable amount of progress has been

made, there are still physical phenomena that need to be

properly included in phase field models if engineering

impact is desired. With this in mind, much effort has

been devoted to account for the effects of stress and

vacancies on both solidification and interdiffusion. It is

also believed that our model for polycrystalline growth

may explain spherulitic growth as well as provide insight

into the observations of Bendersky and NIST coworkers

of a stable glass phase in highly supercooled alloys.

Contributors and Collaborators

W. Boettinger, J. Guyer, D. Wheeler (Metallurgy

Division, NIST); J. Douglas (Polymers Division,

NIST); L. Granasy, T. Pusztai (RISSPO, Hungary)

Advanced Manufacturing Processes
26

Hardness is the primary test measurement

used to determine and specify the mechanical

properties of metal products. The Metallurgy

Division is engaged in all levels of standards

activities to assist U.S. industry in making

hardness measurements compatible with other

countries around the world. These activities

include the standardization of the national

hardness scales, development of primary reference

transfer standards, leadership in national and

international standards writing organizations,

and interactions and comparisons with U.S.

laboratories and the National Metrology

Institutes of other countries.

Carlos Beauchamp and Sam Low

At the international level, we are leading the

 Working Group on Hardness (WGH) under the

International Committee for Weights and Measures

(CIPM). The primary goal is to standardize hardness

measurements worldwide. As secretary of the WGH,

we have led an effort this year to better define the

Rockwell hardness test procedure used by National

Metrology Institutes (NMIs). Other activities include

chairing the ASTM-International committee on

Indentation Hardness Testing and heading the U.S.

delegation to the ISO committee on hardness testing

of metals, which oversees the development of the

respective hardness test method standards published

by those organizations; and as the Secretariat for

the International Organization of Legal Metrology

(OIML) committee on hardness, we have revised

the international requirements for regulating

Rockwell hardness machines.

The primary task at the national level is to

standardize the U.S. national hardness scales and to

provide a means of transferring these scale values

to industry. Currently, we are producing test block

Standard Reference Materials® (SRMs) for the

Rockwell, Vickers, and Knoop hardness scales, as

well as developing new reference standards. Twelve

different microhardness SRMs for Vickers and Knoop

hardness are now available. Fifteen units of a new

steel SRM are in the process of being certified at a

nominal hardness of 760 kgf/mm2 for each of the

Vickers and Knoop hardness scales. These SRMs

are being certified at loads of 2.943 N, 4.905 N, and

9.81 N. In addition, renewal of low inventory of two

of the Knoop Scale SRMs is underway. Ten units of

each of the copper and nickel SRMs are being certified

with nominal hardness levels of 125 kgf/mm2 and

600 kgf/mm2, respectively, at loads of 0.245 N,

0.490 N, and 0.981 N.

We also introduced two new SRMs for the

Rockwell B scale (HRB) to complement the three

SRM Rockwell C scale blocks currently available.

The HRB scale is used for testing softer metals, such as

aluminum, copper and brass. Work is also continuing

to produce a new Rockwell hardness diamond indenter

SRM, which has become feasible due to the successful

completion of a Small Business Innovative Research

(SBIR) Phase-2 project with Gilmore Diamond Tools

to develop an improved method for manufacturing

geometrically correct Rockwell diamond indenters.

Other activities at the national level occurring

this year included: the assessment of commercial

secondary hardness calibration laboratories for the

NIST National Voluntary Laboratory Accreditation

Program (NVLAP) providing direct linkage to the use

of the NIST SRMs; the development of a NVLAP

proficiency testing program for hardness calibration

laboratories; and the development of indentation Finite

Element Analysis models that have been used to analyze

the effect of using different indenter materials for

Rockwell hardness tests in support of proposed

revisions to international test standards.

Contributors and Collaborators

C. Johnson, J. Fink, D. Kelley, L. Ma, H. Gates

(Metallurgy Division, NIST); J. Song (Manufacturing

Engineering Laboratory, NIST); W. Liggett, Jr.,

N. Zhang (Information Technology Laboratory, NIST);

S. Doty, B. Belzer, D. Faison (National Voluntary

Laboratory Accreditation Program, NIST); W. Stiefel

(Technology Services, NIST); M. Mihalec (Gilmore

Diamond Tools, Providence, RI)

Hardness Standardization: Rockwell, Vickers, Knoop

Figure 1: Prototype of new steel microhardness SRM.

Advanced Manufacturing Processes
27

Nanometrology

in determining mechanical properties of thin films

and nanostructures, focuses on developing traceable

calibration methodologies and standard test methods.

We also use atomic force acoustic microscopy,

surface acoustic wave spectroscopy, and Brillouin light

scattering to measure the mechanical properties of

thin films. In addition, we are developing micro- and

nano-scale structures and test methods to measure

strength and fracture behavior of interfaces and

materials having very small volumes.

The chemical and structural characterization and

imaging utilize neutron and x-ray beam lines at three

facilities: the NCNR; the National Synchrotron Light

Source at Brookhaven National Laboratory; and

the Advanced Photon Source at Argonne National

Laboratory. Innovative scattering and spectroscopy

methods are advancing our ability to obtain a wide

range of chemical and structural information at the

nanoscale, including chemical bond identification and

orientation, polyelectrolyte dynamics, and equilibrium

structures. In collaboration with three other NIST

laboratories, we are developing electron microscopy

and spectroscopy instrumentation for quantitative,

3D chemical imaging at the nanoscale. Other

characterization projects include work on gradient

reference specimens for the calibration of advanced

scanning probe microscopy, and the application of

carbon nanotubes as physical probes of cell membranes.

Efforts in the fabrication and monitoring of

nanoscale processes and events include the study of

electrochemical and microfluidic methods for fabricating

nanostructures, novel approaches to nanocalorimetry

for the study of interfacial reactions, in situ observations

of nanoparticle and nanotube dispersion and alignment,

and advanced instrumentation for nanotribology

experiments.

Finally, we have extensive efforts in the theory,

modeling, and prediction of material properties and

behavior extending from nanoscale to macroscale

dimensions. Modeling efforts include large-scale finite

element methods, multiscale Green’s function methods,

classical atomistic simulations, first principles, and

quantum mechanical calculations using density

functional theory. Often, several modeling methods

must be combined into one study to accurately describe

the material behavior; thus, we pay great attention to

the correct interfacing between models operating at

different length scales, to ensure that our models

properly capture the physics of both components

and total systems.

Contact: Gery R. Stafford or John E. Bonevich

(Metallurgy Division)

The burgeoning field of nanomaterials extends

across the full range of traditional material classes,

including all forms of metals, polymers, and ceramics.

No previous materials technology has shown so

prodigiously a potential for concurrent advances in

research and industry as does the field of nanomaterials

in mechanical devices, electronic, magnetic, and optical

components, quantum computing, tissue engineering

and other biotechnologies, and as-yet unanticipated

exploitations of as-yet undiscovered novel properties

of nanoscale assemblies of particles. Already, there

is growing excitement surrounding the ability of

some molecules or particles to self-assemble at

the nanoscale to form new materials with unusual

properties. Nanometrology, i.e., the ability to conduct

measurements at these dimensions, to characterize the

materials, and to elucidate the structure and nature of

these new and novel assemblies, is a requisite and

fundamental cornerstone that must be established

securely if this technology is to flourish.

NIST is uniquely positioned to lead the development

of the measurement methods, instrumentation, standards,

and reference materials that, together, will form the

metrological infrastructure essential to the success

of nanotechnology.

The MSEL Nanometrology Program incorporates

basic measurement metrologies to determine material

properties, process monitoring at the nanoscale,

nanomanufacturing and fabrication techniques, and

structural characterization and analysis techniques

such as advanced imaging and multiscale modeling.

The Program comprises 22 projects in the Ceramics,

Materials Reliability, Metallurgy, and Polymers

Divisions, and includes structural characterization

using neutron scattering at the NIST Center for

Neutron Research (NCNR). The projects cover a

wide range of measurement and characterization

methods grouped into the areas of mechanical

property measurement, chemical and structural

characterization and imaging, fabrication and monitoring

of nanoprocesses and events, and modeling of nanoscale

properties. In each area, we work to advance basic

measurement capabilities and lead the intercomparison,

standardization, and calibration of test methods. The

newly completed Advanced Measurement Laboratory

at the NIST Gaithersburg site provides an incomparable

environment for accurate nanoscale metrology.

In the area of mechanical property measurement,

we are developing and standardizing techniques for

determining nanoscale elastic properties (elastic moduli,

Poison’s ratio, and internal stress), plastic deformation,

density, adhesion, friction, stiction, and tribological

behavior. Work in nanoindentation, used extensively

Program Overview
28

Nanometrology

Electron microscopy is used to characterize the

structure and composition of materials at the

nanometer scale to better understand and improve

their properties. New measurement techniques in

electron microscopy are being developed and

applied to materials science research. The MSEL

Electron Microscopy Facility primarily serves the

Metallurgy, Ceramics, and Polymers Divisions as

well as other NIST staff and outside collaborative

research efforts.

John E. Bonevich

Atomic-scale structure and compositional

 characterization of materials can lend crucial

insights to the control of their properties. For instance,

direct observation of local structures by transmission

electron microscopy (TEM) provides important

feedback to the optimization of crystal growth and

processing techniques. Various characteristics may be

observed such as crystal structure and orientation, grain

size and morphology, defects such as stacking faults,

twins, grain boundaries and second phase particles.

Structure, composition and internal defect structures,

as well as the atomic structure of surfaces and

interfaces, can provide powerful knowledge for

engineering and understanding materials.

The MSEL Electron Microscopy Facility consists of

two transmission electron microscopes, three scanning

electron microscopes, a specimen preparation laboratory,

and an image analysis/computational laboratory. The

JEM3010 TEM can resolve atomic structures and employs

an energy selecting imaging filter (IF) and X-ray detector

(EDS) for analytical characterization of thin foil specimens.

The S-4700-II FE-SEM employs electron backscattered

diffraction/phase identification (EBSD) and EDS systems

to characterize the crystallographic texture and

composition of materials.

Nanoscale Characterization by Electron Microscopy

Figure 1: MgO cubes with surfaces decorated by small gold

particles. These particle ensembles are used in model studies of

3D chemical imaging at the nanoscale (electron tomography).

Figure 2: Confined Si single electron transistor device.

Highlights from the EM Facility for FY2004 include:

■ A new, high-sensitivity EBSD CCD camera

which acquires in excess of 70 patterns/second,

was installed on the FE-SEM.

■ 3D Chemical Imaging at the Nanoscale, a collaborative

project with CSTL and PL on tomographic

characterization of materials, was initiated (Figure 1).

■ Research collaboration with the Semiconductor

Electronics and Electricity Divisions (EEEL) has

characterized quantum effects in confined Si devices

(Figure 2).

■ Sub-100 nm Ag interconnects formed by

superconformal electrochemical deposition was

characterized.

Contributors and Collaborators

D. Josell, T. Moffat, L. Bendersky (Metallurgy

Division, NIST); I. Levin, B. Hockey (Ceramics Division,

NIST); J.H.J. Scott (Surfaces & Microanalysis Science

Division, NIST); Z. Levine (Optoelectronics Division,

NIST); E. Vogel (Semiconductor Electronics Division,

NIST)
29

Nanometrology

Novel structures and devices can be formed

through template electrodeposition. The ultimate

pattern resolution is determined by the size and

packing of molecules that comprise the template

and their ability to inhibit or catalyze various

electrochemical reactions. In the past year, the

effect of molecular functionality on the metal

deposition process has been explored.

Thomas P. Moffat and Michael J. Fasolka

Over the last decade, electrochemical processing

 has been undergoing a renaissance with the

fabrication of new materials and novel microstructures.

The development of new measurement techniques and

metrological tools for studying controlled growth at

fine length scales is the primary objective of this effort.

2. The role of molecular functionality of the surfactant

and robust design rules; and

3. The anisotropy induced in the electrocrystallization

reaction rate for a given surfactant.

As an example, an alkanethiol monolayer film can

either block or accelerate metal deposition depending

on the molecular functionality of its terminal group.

A dynamic range spanning several orders of magnitude

is possible depending on the system in question (Figures

1 and 2). Based on these measurements, selective metal

deposition may be obtained by patterning a substrate

with the appropriate molecule.

Nanostructure Fabrication Processes:

Patterned Electrodeposition by Surfactant-Mediated Growth

Figure 1: Influence of small changes in molecular structure,

i.e., SO3

– vs. CH3, on the rate of copper deposition.

Figure 3: Spatially patterned monolayer films used to control

nucleation and anisotropic growth of copper crystals.

Through contact printing, higher resolution patterning

is possible, along with some interesting opportunities for

high-throughput combinatorial research. By varying the

surface chemistry, growth of isotropic or faceted crystals

has been shown to be possible (Figure 3).

Contributors and Collaborators

D. Josell, J. Mallett, W.F. Egelhoff (Metallurgy

Division, NIST); M. Walker, L. Richter (CSTL, NIST)

Figure 2: Copper deposition on an alknethiol derivatized gold

substrate only occurs in regions bearing –SO3

– terminated

molecules.

The three key metrology issues addressed are:

1. The rate differentiation accessible via surfactant

mediated metal film growth;
30

Nanometrology

The microelectronics community uses

electrodeposition to produce solderable surface

finishes, magnetic recording media, and copper

interconnections in printed circuit boards and

integrated circuits. These films tend to develop

sizable mechanical stresses that can lead to loss of

adhesion and the generation of bulk and surface

defects. This project focuses on the measurement

of these stresses which should enable the

development of effective mitigation strategies.

Gery R. Stafford and Ole Kongstein

Electrodeposited films tend to develop sizable

mechanical stresses during deposition due to the

nucleation and growth process or solution additives and

alloying elements. We have established an optical bench

dedicated to the in situ measurement of growth and

residual stress during electrodeposition using the wafer

curvature method. In one approach, a substrate of

borosilicate glass is evaporated with 250 nm of gold.

The force exerted on the cantilever by the electrodeposit

causes curvature of the cantilever, which is monitored

during electrodeposition. Forces on the order of

0.03 N/m can be resolved during film deposition.

negative deposition potentials. As the deposit thickens,

the average film stress decreases and becomes

compressive in deposits formed at small deposition

overpotentials. In the physical vapor deposition literature,

this compressive stress has been attributed to the

non-equilibrium concentration of mobile ad-atoms on

the surface that are driven into the grain boundaries.

Nanostructure Fabrication Processes:

Thin Film Stress Measurements

Figure 1: Average film stress during copper deposition.

Figure 1 shows the average in-plane stress associated

with the deposition of copper from an additive-free sulfate

electrolyte. The rapid rise in tensile stress (within the

first 20 nm) and its dependence on deposition potential

are consistent with nuclei coalescence and grain boundary

formation. The highest tensile stresses are associated

with high nucleation densities which are obtained at more

Figure 2: Force/ width exerted on the cantilever during the

electrochemical processing of Sn on Cu.

We have also examined the force exerted onto a copper

cantilever electrode during the deposition of matte tin (Sn),

Figure 2. This is a particularly important system since

the growth of tin whiskers, known to produce electrical

short circuits and device failure, has been attributed to

both the residual stress in the electrodeposit as well as

that generated from intermetallic formation at the Sn-Cu

interface. The force curves show the following features:

a tensile to compressive transition during deposition, a

significant tensile relaxation when plating is discontinued,

the development of tensile stress while the deposit is at

open circuit, and a residual tensile stress after the deposit

is electrochemically dissolved. The two latter features

are attributed to the formation of the Cu6Sn5 intermetallic

(IMC) at the Sn-Cu interface. A tensile stress is generated

since the IMC has approximately 6 % smaller volume than

a rule of mixture combination of the Sn and Cu reactants.

Calculating the IMC thickness from the difference in Sn

deposited and stripped, a nominal stress in the intermetallic

was estimated to be 1.2 GPa after only one hour. Future

work will focus on determining to what degree this

increases the compressive stress in the Sn electrodeposit.

Contributors and Collaborators

W. Boettinger, U. Bertocci (Metallurgy Division, NIST)
31

Nanometrology

Knowledge of mechanical behavior is critical

when designing for device performance and

reliability, even for “non-mechanical” systems.

However, nanoscale mechanical behavior

(including failure) is inherently difficult to measure

accurately, and existing modeling tools are only

qualitative at best. We are developing modeling

techniques that provide quantitative predictions

and are validating these results experimentally.

Lyle E. Levine and Anne M. Chaka (838)

Mechanics at the nanoscale is inherently difficult to

model accurately. Finite element modeling (FEM)

can effectively capture the elastic behavior of macroscopic

structures but includes no accurate failure criteria

since this depends upon atomic-scale behavior.

Classical atomistic simulations can handle enough atoms

(millions to billions) to model such events, but these

potentials become inaccurate for large strains and they

cannot effectively handle chemistry. Quantum-mechanicsbased simulations using density functional theory (DFT)

are extremely accurate and handle the chemistry exactly,

but such simulations are so CPU intensive that they

can handle only a few hundred atoms. A combination

of all three modeling techniques is required to

accurately model device behavior at the nanoscale.

the predicted elastic displacement fields to generate

boundary conditions and initial atom positions for

an atomistic simulation using classical potentials.

The use of classical potentials in a large simulation cell

allows the correct propagation of the long-range stresses

to the critical regions where bond distortions are large or

where chemistry effects need to be explored. In these

critical regions, the techniques embed a DFT simulation.

Iteratively, the critical region is relaxed using DFT, and

the classical cell is relaxed using a Monte-Carlo algorithm.

The first application of this hybrid technique was to

determine the vacancy formation energy in aluminum as

a function of distance (at a fixed angle) away from an

edge dislocation. The simulation geometry is shown in

Figure 2. The boundary conditions and initial atomic

positions were calculated from the known elastic

displacement field of an edge dislocation.

Nanomechanics: Coupling Modeling with Experiments

Figure 1: FEM model of a rigid 100 nm diameter sphere

indenting an Al sample to a depth of 10 nm.

Over the past year, we have developed techniques

to handle such multiscale modeling for quasistatic

applications. At the macroscale, FEM is used to simulate

the elastic behavior of a nanomechanical system. Figure 1

shows an example in which an Al sample is being indented

by a rigid 100 nm diameter sphere. The indenter and

three of the sample quadrants have been removed to

highlight the resulting Von Mises stress distribution after

indenting 10 nm. The FEM mesh is fine enough to use

Figure 2: Diagram of a hybrid simulation for obtaining the

vacancy formation energy at different positions relative to an

edge dislocation. The large box represents the EAM cell in

which the DFT region containing the vacancy was embedded.

After an initial dislocation nucleation event,

nanoindentation progresses through the complex

evolution of dislocation structures. For example, the

raised lip around the indent is produced by large

numbers of dislocations exiting the surface. We are

working on modeling the early stages of this process

using 3D dislocation dynamics and assuming a random

distribution of dislocation sources in the sample.

Finally, connection to experimental measurements

requires careful force calibration of the indenter and

calibrated atomic force microscopy measurements (AFM)

of the indenter tip. These calibrations are mostly complete,

and the AFM data will be used to generate a FEM mesh

for the simulations. Bulk single-crystal copper samples

are being cut and polished using non-contact chemical

methods to minimize the dislocation density.

Contributors and Collaborators

S.M. Khan, G. Levi, L. Ma, F. Tavazza (Metallurgy

Division, NIST); B. Hockey, R. Machado, D. Smith,

R. Wagner, D. Xiang (Ceramics Division, NIST)
32

Program Overview

and enamel. This approach will ultimately lead to

materials with improved durability, toughness, and

adhesion to contiguous tooth structure. We also

collaborate with the ADAF to develop metrology

for the biocompatibility of synthetic bone grafts.

In this era of interdisciplinary research,

we provide an added dimension. By taking a

physical/mechanical approach to how cells function,

respond, and remodel in interaction with synthetic

materials, we provide skill sets typically absent in the

biomedical community. Mechanical properties issues

also arise when considering synthetic bone grafts

and tissue engineering scaffolds. Complementing

traditional bulk mechanical property measurements,

combinatorial approaches are being developed to

identify compositions and surface features that

affect properties such as biocompatibility and

mechanical durability.

Our mechanical property metrology extends further

to biological systems that span the range from individual

neurons and muscle cells to complete pulmonary

arteries. This necessitates the development of unique

mechanical testing platforms and application of a

materials science approach to understanding integrated

properties. Recently, we have developed a bioreactor

capable of applying biaxial stresses and allowing

monitoring of the stress and strain of a two-dimensional

scaffold sheet during tissue growth.

Fundamental to the Biomaterials program is

recognition of the need for an integrated systems

approach. Collaborations among and between project

teams are critical to progress against the ambitious

goals of this program.

Contact: Eric J. Amis (Polymers Division),

Lyle E. Levine (Metallurgy Division)

New materials and devices are radically changing

the treatment of injury and disease, yet it is clear that

within this rapidly evolving segment of the materials

industry, a basic measurement infrastructure does

not exist. The Biomaterials Program develops

measurement methods, standards, and fundamental

scientific understanding at the interface between the

materials and biological sciences. For the health care

industry, we focus on dental and medical sectors that

apply synthetic materials for replacement, restoration,

and regeneration of damaged or diseased tissue.

Three primary foci exist within this program:

biocompatibility, biomaterials characterization, and

materials measurements applied to biological systems.

Whether the medical issue involves implanting

a hip- or knee-joint prosthesis, a synthetic bone graft,

or a tissue engineering scaffold into the human body,

one primary issue is biocompatibility. Using our

expertise in materials science, we have developed

suitable Reference Materials (RM) for investigating

biocompatibility and implant suitability. Research has

focused on measuring cellular response to powders

and bulk materials that are candidates for implants;

recently, we produced a realistic wear particle Standard

Reference Material (SRM® 2880) for bioactivity testing.

Work on quantitative methods of biomaterials

characterization includes assays for adhesion,

viability, proliferation, and differentiation of bone

cells, 3-dimensional structural/functional imaging

of tissue in-growth, and biochemical assays to

quantify inflammatory responses to synthetic materials.

The focus of this effort is bridging the gap between

fundamental knowledge and the product development

needs in industry. For example, in collaboration with

the Chemical Science and Technology Laboratory,

we are developing measurement methodologies and

reference materials to assess interactions in complex

systems of living cells with synthetic materials.

The expected outcome of this work includes reference

substrates that induce specific cellular responses,

and engineered DNA vectors to act as fluorescent

reporters of cellular responses.

Another example of our effort to bridge this gap

is our collaboration with the dental industry, which

is primarily composed of small manufacturers with

limited R&D capability. Collaborations with the

American Dental Association Foundation (ADAF)

develop improved materials and materials measurements

techniques, patent and license these inventions, and,

most importantly, provide a technical foundation.

Research focuses on improved understanding of the

synergistic interaction of the phases of polymer-based

composites and the mechanisms of adhesion to dentin

Biomaterials
33

Biomaterials

Modeling the behavior of complex materials

requires detailed knowledge of the underlying

three-dimensional microstructure. Ultra-small-angle

X-ray scattering (USAXS) imaging is a new class

of synchrotron X-ray imaging techniques that uses

USAXS as the contrast mechanism. The technique

provides imaging and statistical data that cannot

be obtained using any other experimental methods.

It has now been applied to characterize artificial

tissue scaffolds and human cartilage in 3D.

Lyle E. Levine

USAXS imaging was developed by NIST researchers

and was first demonstrated in May 2000. Advantages

over existing X-ray imaging techniques are its inherently

higher contrast and its USAXS-derived ability to provide

quantitative data on object shapes and size distributions.

USAXS imaging is applicable to a wide range of material

systems including metals, ceramics, polymers, composites

and biological materials. Over the past year, work has

concentrated on two main areas. First, the final hardware

components were installed, greatly improving the USAXS

and USAXS imaging capabilities, and, second, a wide range

of material systems, including biological ones, have

been explored to determine where USAXS imaging

can have the greatest impact.

The USAXS imaging experiments are conducted on

the UNICAT sector 33 insertion-device beamline at the

Argonne National Laboratory Advanced Photon Source

(APS). A high-intensity, nearly-parallel, monochromatic

X-ray beam passes through entrance slits that define

the size, shape and position of the beam. The angular

divergence in the X-ray beam is reduced by using multiple

Bragg reflections on <111> Si crystals referred to as

the collimator. Within the sample, local density variations

from the microstructure produce X-ray scattering at

small angles. The X-rays leaving the sample are then

angle-filtered using a pair of <111> Si crystals referred

to as the analyzer. The only X-rays from the sample that

can pass through the analyzer are those scattered by the

microstructure at a specific angle, where this angle can

be selected by rotating the analyzer. Images are then

formed by either exposing nuclear emulsion plates or

using the NIST high-resolution X-ray camera system

that was completed in FY 2003.

During FY 2004, the USAXS imaging instrument

was declared fully operational after installation and

testing of the last major hardware component, a new

collimator system in which the surfaces of the two Si

crystals were chemo-mechanically polished to minimize

image aberrations. The new collimator was designed,

built, and paid for by the APS and meets all of our

specifications. Only minor problems were encountered

during testing, and the required modifications are

nearly completed.

USAXS and USAXS Imaging of Biomaterials

Figure 1: Identical sample volumes of an artificial tissue scaffold

imaged at scattering vectors of a) q = 0 Å–1 and b) q = 0.0005 Å–1.

Samples studied this year include artificial tissue

scaffolds composed of porous poly-caprolactone (PCL),

human cartilage, several metal alloys and a composite of

carbon black in poly-methylmethacrylate. Figure 1 shows

images of a PCL sample with 50 % porosity that was

cultured with osteoblasts for 28 days. Figure 1a was

taken with a 0o scattering angle (radiographic) and shows

the overall structure of the scaffold. Figure 1b, from

the same sample volume, was acquired at a scattering

vector of q = 0.0005 Å–1 and shows the distribution of

osteoblasts on the scaffold surfaces. Stereopairs were

used to examine the cell positions in 3D. A full rotation

sequence was acquired at q = 0 Å–1, and a tomographic

reconstruction produced a complete 3D description of

the scaffold structure.

A detailed paper describing the USAXS imaging

instrument along with the underlying theory was

completed and accepted for publication.

Contributors and Collaborators

J. Dunkers (Polymers Division, NIST); J. Ilavsky,

G. Long (Argonne National Laboratory); P. Jemian

(UNICAT); C. Muehleman (Rush Medical College)

 ́  ́

 ́

 ́
34

Program Overview

Materials for Electronics

The U.S. electronics industry faces strong

international competition in the manufacture of smaller,

faster, more functional, and more reliable products.

Many critical challenges facing the industry require

the continual development of advanced materials

and processes. The NIST Materials Science and

Engineering Laboratory (MSEL) works closely with

U.S. industry covering a broad spectrum of sectors

including semiconductor manufacturing, device

components, packaging, data storage, and assembly,

as well as complementary and emerging areas such as

optoelectronics and organic electronics. MSEL has a

multidivisional approach, committed to addressing the

most critical materials measurement and standards

issues for electronic materials. Our vision is to be

the key resource within the Federal Government for

materials metrology development and will be realized

through the following objectives:

■ Develop and deliver standard measurements and data;

■ Develop advanced measurement methods needed by

industry to address new problems that arise with the

development of new materials;

■ Develop and apply in situ as well as real-time, factory

floor measurements, for materials and devices having

micrometer- to nanometer-scale dimensions;

■ Develop combinatorial material methodologies for

the rapid optimization of industrially important

electronic materials;

■ Provide the fundamental understanding of the

divergence of thin film and nanoscale material

properties from their bulk values;

■ Provide the fundamental understanding of materials

needed for future nanoelectronic devices, including

first principles modeling of such materials.

The NIST/MSEL program consists of projects led

by the Metallurgy, Polymers, Materials Reliability, and

Ceramics Divisions. These projects are conducted in

collaboration with partners from industrial consortia

(e.g., International SEMATECH), individual companies,

academia, and other government agencies. The program

is strongly coupled with other microelectronics

programs within the government such as the National

Semiconductor Metrology Program (NSMP). Materials

metrology needs are also identified through the

International Technology Roadmap for Semiconductors

(ITRS), the IPC Lead-free Solder Roadmap, the

National Electronics Manufacturing Initiative (NEMI)

Roadmap, the Optoelectronics Industry Development

Association (OIDA) Roadmap, IPC (the International

Packaging Consortium), and the National [Magnetic

Data] Storage Industry Consortium (NSIC) Roadmap.

In each of these areas, MSEL researchers have made

substantial contributions to the most pressing technical

challenges facing industry, from new fabrication methods

and advanced materials in the semiconductor industry, to

advanced packaging materials, to magnetic data storage.

Below are just a few examples of MSEL contributions

over the past year.

Advanced Gate Dielectrics

To enable further device scaling, the capacitive

equivalent thickness (CET) of the gate stack thickness

must be 0.5 nm to 1.0 nm. This is not achievable with

existing SiO2/polcrystalline Si gate stacks. Given the

large number of possible choices for these new layers,

the only feasible approach to understanding the complex

materials interactions that result at the gate dielectric/

substrate and gate dielectric/metal gate electrode

interfaces is through the application of combinatorial

methodologies. This same methodology and apparatus

are applicable to a wide variety of problems in the

electronic materials field.

Sub-100 nm Nanofabrication

The continual decrease in feature size has been the

driving force for advances in the semiconductor industry.

Current structures have 90 nm dimensions with planned

nodes at 65 nm and 35 nm structures. Advanced

measurements of the patterning materials (photoresists),

are needed to enable future large scale manufacturing of

smaller devices. MSEL utilizes advanced x-ray and

neutron tools to provide insight into the feasibility

and optimization of these important processes.

Advanced Metallization

Electrodeposited copper is rapidly replacing aluminum

for on-chip “wiring” because of its lower electrical

resistivity, superior electromigration behavior, and the

ability to fill fine features without the formation of seams

or voids. As feature dimensions go below 100 nm,

difficulties in maintaining performance are anticipated.

These issues are addressed through a combination of

modeling and experimental efforts.

Test Methods for Embedded Passive Devices

Significant advantages arise if passive devices are

integrated directly into the circuit board as embedded

passive devices rather than discretely attached with

automated assembly. New metrology methods were

developed to address the needs of the electronic industry.

Two test methods were completed and have received

wide acceptance by industry as new methods to accelerate

the development of embedded passive device technology.

Contact: Martin L. Green (Ceramics Division),

Eric K. Lin (Polymers Division),

Daniel Josell (Metallurgy Division)
35

Materials for Electronics

The development of wide-band-gap semiconductor

optoelectronic and electronic devices is hindered

by poor electrical contact performance. Reliability

issues for contacts include the requirements to

be low-resistance, morphologically smooth and

thermally stable. This project develops a strategy to

improve electrical and morphological characteristics

of Ohmic contacts to GaN thin films by optimizing

metallization schemes using an integrated phase

diagram/combinatorial approach.

Albert V. Davydov and William J. Boettinger

Ti/Al/Ti/Au metallizations are the most commonly

used electrical contact to n-type GaN-based

device structures. However, the overall composition

(i.e., thickness ratios) and the thermal processing

of metal layers are not yet optimized. A rationale for

designing the optimum metallization scheme also has

not been developed. This work demonstrates that the

phase diagram approach, along with a combinatorial

experimentation method, is a useful tool in the design

and optimization of electrical contacts to GaN and

other wide-band-gap semiconductors.

A combinatorial library of Ti/Al/Ti/Au metallization

was prepared and characterized electrically and

microstructurally in order to establish optimum

composition and processing parameters for the realization

of high-quality Ohmic contacts. An array of metallic

elements with varying Ti/Al/Ti/Au thicknesses was

deposited by combinatorial ion-beam sputtering (CIBS)

on n-GaN/c-sapphire substrate followed by rapid-thermal

annealing (RTA) in the 600 oC to 900 oC temperature

range. The library design of metal compositions and RTA

temperatures was guided using the Al-Au-Ti phase diagram

so that various Ti/Al/Ti/Au contact compositions

represented different regions on the phase diagram.

Four-probe transmission-line-method and Hall electrical

measurements were used to assess contact resistivity

and GaN sheet resistance. X-ray diffraction, white-light

interferometric microscopy, atomic-force microscopy,

field-emission scanning-electron-microscopy, and

transmission-electron-microscopy were used to evaluate

the microstructure and morphology of contacts and

the metal/GaN interfaces. The most Au-rich/Ti-poor

metallization (E in Figure 1a), Ti(20 nm)/Al(85 nm)/

Ti(15 nm)/Au(150 nm) with an RTA of 800 oC/30 s

in argon, produced the lowest (ρ = 1.3 × 10–5 Ω × cm2)

contact resistivity with reasonable (rms < 150 nm) surface

morphology. However, the most Al-rich metallization

(D in Figure 1a), Ti(20 nm)/Al(170 nm)/Ti(5 nm)/

Au(50 nm) with RTA of 750 oC/30 s in argon, produced

superior surface morphology (rms = 20 nm) and

comparable resistivity of ρ = 2.2× 10–5 Ω × cm2. It is

suggested that scheme (E) with the Au-rich contact can

be used for operating in oxidizing environments, where

thick Au top layer will serve as a protective cap layer,

while scheme (D) can be suitable for applications where

contact surface roughness is critical. According to XRD

results, the superior surface morphology of contacts

in the D-series correlates with the absence of phase

transformations in the 600 oC to 900 oC temperature

interval after the initial formation of Al2Au and Al3Ti

phases in metal films.

The advanced metallizations developed in the project

will be validated in industrial high-electron mobility

transistors (HEMTs) at Northrop–Grumman Corporation.

Contributors and Collaborators

L.A. Bendersky, D. Josell, U.R. Kattner, A.J. Shapiro

(Metallurgy Division, NIST); J.E. Blendell, R.S. Gates,

P.K. Schenck, M.D. Vaudin (Ceramics Division, NIST);

T. Zheleva (Army Research Laboratory); H.G. Henry

(Northrop–Grumman); Q.Z. Xue (Intematix Corp.);

A. Motayed (Howard University); I. Takeuchi (Univ. of

Maryland)

Combinatorial/Phase Diagram Approach for

Metallization to Wide-Band-Gap Semiconductors

Figure 1: a) 36-element combinatorial library of annealed

Ti/Al/Ti/Au contacts on n-GaN: metal compositions change

along the x-axis from A to F, annealing temperature changes

from 600 oC to 900 oC along the y-axis; “X”s mark the library

elements with the lowest resistivity and smoothest morphology;

b) map of surface roughness of the combinatorial array:

yellow-shaded area represents the contacts with the smoothest

(rms < 60 nm) morphology; c) map of electrical resistivity of the

combinatorial array: red-shaded area represents the contacts

with the lowest (ρ < 3 × 10–5 Ω × cm2) resistivity.
36

Materials for Electronics

As the microelectronics industry moves towards

Pb-free assemblies, reliability has become a major

concern. Pb-free coatings of nearly pure tin,

used as a protective layer to maintain solderability

on Cu leadframes and connectors, tend to grow

“whiskers” which can cause shorts across

component leads. Copper additions to the Sn

protective layer have been considered by industry

since the Sn-Cu-Ag is likely to be the Pb-free

bulk solder of choice for industrial applications.

However, measurements made at NIST indicate

that the addition of Cu tends to promote whisker

growth. Our goal is to better understand how

copper and other solutes impact the growth

of whiskers on electrodeposited Sn.

Gery R. Stafford, William J. Boettinger,

and Kil-Won Moon

Whiskers are generally believed to grow to

relieve residual stress in tin and other coatings.

However, the origin of this stress has not been

definitively determined. The addition of certain solutes,

such as Bi and Pb, are known to retard whisker growth

in electrodeposited tin coatings, while solutes, such as

Zn are known to promote growth. Previous work

at NIST has shown that low levels of Pb reduce the

residual compressive stress in Sn-Pb electrodeposits,

while the addition of Cu increases the residual

compressive stress. Current research focuses on the

influence of solute type and concentration on residual

film stress, stress relaxation, and whisker formation.

Metallographic analysis of Sn-Cu electrodeposits

indicates that the Cu is present as the Cu6Sn5 intermetallic

compound (IMC) which is observed both in the grains

and along the grain boundaries. It is unlikely that significant

amounts of this complex IMC are formed directly during

deposition. Rather, we believe that the as-deposited

alloy is a supersaturated solid solution of Cu in Sn that

transforms to an equilibrium mixture of Sn and Cu6Sn5

either during or soon after deposition.

In solid solution, Cu is presumed to occupy interstitial

sites within relatively large square channels that exist in

the body-centered tetragonal (bct) Sn structure. This

gives rise to the anomalously fast diffusion of Cu in the

c-direction of the Sn lattice. In this configuration, it is

assumed that the Cu does not alter the lattice volume of

the Sn. It is further presumed that as Cu6Sn5 precipitates

within the deposit, the Cu exits the interstitial sites in the

Sn phase and occupies volume more typical of its atomic

size; thus, the volume of the entire deposit increases.

We estimate the volumetric strain for Cu6Sn5 precipitation

from a 1 % Cu solid solution to be about +0.004. The

resultant stress generated in the electrodeposit as a result

of the IMC precipitation is then on the order of –95 MPa

(compressive). This, of course, assumes that Cu6Sn5

forms from the solid solution after the deposit has

been formed.

Lead-Free Surface Finishes: Sn Whisker Growth

Figure 1 shows a series of x-ray diffraction patterns

that were taken at the Advanced Photon Source, using

synchrotron radiation, during and after the deposition

of a Sn-Cu alloy onto a tungsten substrate. The inset

pattern was taken during the 2-minute deposition while

the remaining patterns were taken 3 minutes apart after

deposition was complete. The data show that although

a small amount of Cu6Sn5 is present when deposition

is stopped (inset), the bulk of the IMC forms in the

45 minutes following deposition. Although the Sn

reflections decrease as the IMC forms, the peaks do

not change position indicating that the lattice volume of

the Sn is constant. This supports the assumption that

interstitial Cu does not alter the lattice volume of bct Sn.

These results indicate that IMC formation occurs after

deposition is complete and is a likely cause of the higher

compressive stress observed in Sn-Cu alloy deposits.

Contributors and Collaborators

J.E. Guyer, C.E. Johnson, M.E. Williams

(Metallurgy Division, NIST); M.D. Vaudin (Ceramics

Division, NIST); D.R. Robinson, D. Wermeille

(Advanced Photon Source, ANL)

Figure 1: In situ x-ray diffraction (λ = 0.127 Å) showing growth

of the Cu6Sn5 110 reflection in the 45 minutes following deposition

of bright Sn-Cu alloy from commercial methanesulfonate electrolyte.
37

Lead-Free Solders and Solderability

Materials for Electronics

Solders and solderability are increasingly tenuous

links in the assembly of microelectronics as a

consequence of ever-shrinking chip and package

dimensions and the international movement toward

environmentally friendly lead-free solders. In

collaboration with the NEMI Pb-Free Assembly

Project, we are providing the microelectronics

industry with measurement tools, data, and

analyses that address national needs in the

implementation of lead-free solders.

Ursula Kattner and Carol Handwerker

Since 1999, NIST has served a major role in National

Electronics Manufacturing Initiative (NEMI)

projects to assist the microelectronics industry implement

Pb-free solders. NEMI is an industry-led consortium

of approximately 65 electronics manufacturers,

suppliers and related organizations brought together to

facilitate leadership of the North American electronics

manufacturing supply chain. This move toward Pb-free

solders is a direct result of the European Union ban, starting

in 2006, on Pb-containing solders in electronic products.

NEMI and NIST have worked together to respond

to the identified needs by:

1) Identifying and providing the most important

lead-free solder data for the microelectronics

community (including the definitive database

on thermodynamic properties of Pb-free alloys),

providing an analysis of the mechanical behavior of

Sn-Ag-Cu alloys, and disseminating such data on the

NIST website (see “Delivery of Thermodynamics

and Kinetic Data” in this volume).

2) Developing and widely disseminating a Recommended

Practice Guide on Test Procedures for Developing

Solder Data.

3) Providing a list of literature references on alloys,

processing, reliability, environmental issues, and

components for the implementation of lead-free solders.

4) Completing the microstructure-based failure analysis

on all thermally cycled assemblies as part of the

NEMI project’s full-scale reliability trials.

5) Providing chapters on the materials science of

Pb-free solder alloys for inclusion in four separate

books on Pb-free solder implementation.

Although the NEMI Pb-Free Assembly Project ended

in 2003, in 2004 we continued to serve as an information

resource to the microelectronics industry on issues related

to the effects of alloy composition, reflow temperature

and furnace profiles for best melting and solidification

behavior of solders when circuit boards are assembled,

and to the effects of Pb contamination on alloy melting

and assembly reliability. This activity culminated in a

Circuits Assembly article by Alan Rae, VP of Technology

for Cookson Electronics, and Carol Handwerker of NIST

on the range of acceptable alloy compositions in the

Sn-Ag-Cu system. The following excerpt gives the

NEMI position, and effectively the U.S. position, on

the acceptable composition ranges for the new international

standard Pb-free alloy and allows both the U.S. and the

Japanese preferred alloy compositions based on analyses

of NIST thermodynamic data:

Although the composition of some of the alloys

being commercialized varies slightly from the NEMI

composition, the NEMI alloy is representative of

the acceptable range of lead-free solders. Tin–silver–

copper formulations with silver content between

3.0 [mass] % and 4.1% and copper between 0.5%

and 1.0% are virtually indistinguishable in terms of

melting point and process features. The NEMI alloy

provides a model system for industry that is well

characterized, and several NEMI members currently

are using the alloy in production. The focus on

a single lead-free alloy has helped to accelerate

industry convergence on standard solder

formulations, manufacturing processes and,

ultimately, the timely and cost-effective

conversion to lead-free assembly.

“The NIST group performed a significant service to

industry by being the focal point for development of a

reliable technology base to support the choice of a new

lead-free alloy. They also led the way for further work

on issues such as tin whiskers, which emerged from

the initial lead-free work. NIST provided not only a

strong technical basis but, by verifying reliability and

comparing alternatives, enabled industry to choose

an alloy based on extensive investigation.”

Dr. Robert C. Pfahl, Jr., Director

International and Environmental R&D,

Motorola, (retired), and Vice President

Operations, NEMI, (current)

Contributors and Collaborators

W.J. Boettinger, K.W. Moon, T. Siewert,

D. McCowan, L.C. Smith, S.W. Claggett, M.E. Williams

(NIST); J.P. Clech (EPSI, Inc.); J. Bath (Solectron);

R. Gedney (NEMI); E. Bradley (Motorola); J.E. Sohn

(NEMI, formerly Lucent); A. Rau (Cookson Electronics);

E. Benedetto (HP); R. Charbonneau (StorageTek)
38

Materials for Electronics

Copper wiring in on-chip electrical conductors

has reached dimensions so small that electrical

resistivity is no longer constant. The higher

resistivity induces greater power dissipation,

aggravating chip cooling problems. We have

quantified the microstructural factors behind this

increase for silver wires, where silver has the

highest electrical conductivity of any metal.

Daniel Josell and Thomas P. Moffat

As dimensions of transistors in integrated circuits

 shrink, the dimensions of the metal wires

connecting them shrink as well. Dimensions of the

wires, and internal grains, are now at approximately

100 nm, similar to the intrinsic mean-free-path lengths

of the conduction electrons. Scattering from wire

surfaces and grain boundaries is significantly reducing

electrical conductivity in such small conductors.

Upcoming dimensional requirements, as specified

in the International Technology Roadmap for

Semiconductors, require determination of the origin

and magnitude of the resistivity increase in order to

direct research that might mitigate these size effects.

To address these issues, we have measured

size-dependent resistivity of silver wires 100 nm to

300 nm tall for widths ranging from approximately

50 nm to 840 nm, produced by electrodeposition on

patterned wafers followed by a combined chemical

mechanical planarization and oblique ion-polishing

process. Silver was selected because of its high

electrical conductivity and our recent development

of a bottom-up “superfill” process for creating

void-free and seam-free wires (Figure 1).

Electrical Properties of On-Chip Interconnections

Figure 1: Transmission electron microscope images of silver

wires cross-sectioned after electrical measurement. The higher

aspect ratio (height/width) wires contain multiple grains while

the lower aspect ratio wires contain only twin boundaries.

To interpret the resistivity data, the Fuchs–Sondheimer

formalism (diffuse scattering of electrons on the wire

surfaces) was extended to permit a nonzero specular

component for surface scattering. The analysis used an

existing formalism to account for grain boundary scattering.

The resulting equations permit quantitative comparison

to experiment (Figure 2).

Significantly, the analysis shows that surface

scattering alone is not capable of explaining the

observed behavior. Grain boundary scattering is found

to contribute a similar, or larger, amount to the overall

increase. As a result, the potential payoff of increasing

the grain size to decrease grain boundary scattering is

recognized to be at least as large as that which might be

obtained by smoothing surfaces to increase specularity.

Contributors and Collaborators

G. McFadden (Mathematical and Computational

Sciences Division, NIST); R.R. Keller, Y.-W. Cheng

(Materials Reliability Division, NIST); C. Witt (Cookson–

Enthone); C. Burkhard, Y. Li (Clarkson University)

Figure 2: Electrical properties of 300 nm tall silver wires as a

function of the wire width. Curves are the result of calculations

including intrinsic, surface and grain boundary scattering of

electrons. The sharp increase at ≈ 100 nm is associated with defects.
39

Materials for Electronics

In order to pursue the rapid development path

set out for hard drives and magnetic memory,

industry needs the ability to measure and control

magnetization on nanometer length scales and

nanosecond time scales. This project focuses

on the metrology of dynamics and damping in

magnetic thin films, especially on the effects

of nano-scale dimensions and defects in

ferromagnetic resonance measurements.

Robert D. McMichael

We are developing ferromagnetic resonance (FMR)

techniques to measure the static and dynamic

properties of thin films and patterned arrays of

technologically important ferromagnetic metals and their

interfaces with normal metals. The primary results

include measurements of surface anisotropy, which

becomes increasingly important for nanoscale damping,

which governs behavior on the sub-nanosecond time

scale, and assessment of the magnetic homogeneity

of thin films or patterned arrays of magnetic bits.

These results are communicated to the magnetic data

storage industry through conference presentations,

journal articles and site visits.

For nanostructured materials, surface effects

and interfacial effects are important. For example,

micromagnetic calculations show that switching

behavior of magnetic memory cells will be affected by

surface anisotropy on the edges of the lithographically

patterned elements, an effect that has not been

appreciated until recently. Measuring the anisotropy

of films of varying thickness with ferromagnetic

resonance enables the determination of surface

anisotropy values for Permalloy that will be used

in the micromagnetic design of MRAM cells.

A continuing thrust of this project has been the

development of models that describe broadening of the

FMR linewidth by defects. These models, which are

specifically designed for thin films, account for both

inhomogeneity and magnetic interactions. Our earlier

models were restricted to “local” defects such as

anisotropy. One important application of these models

is as a method for measurement of anisotropy variations

and axis alignment in perpendicular recording media.

This year, we have capped off the model development

with a model for the non-local effects of film roughness.

Nanomagnetodynamics

Figure 1: Surface anisotropy measurements for Permalloy films

with different normal metal over/underlayers. The slopes of the fit

lines correspond to surface anisotropy.

Testing of the roughness-linewidth model involved

making variable roughness substrates, characterizing

the roughness by atomic force microscopy (AFM),

and measuring nearly conformal Permalloy overlayers

in FMR. Using only the AFM microstructural data

and the known properties of Permalloy, and assuming

conformal roughness, the model predictions agreed

extremely well with the measurements. Allowing

one free parameter describing thickness variations,

the agreement with the experiment is nearly perfect.

Validation of this model is the first example of

linewidth modeling based entirely on the measured

microstructure.

Contributors and Collaborators

J.O. Rantschler, B.B. Maranville, J. Mallett,

T. Moffat, W.F. Egelhoff, Jr., A.P. Chen (Metallurgy

Division, NIST); J.A. Borchers, S.K. Satija (NIST

Center for Neutron Research); W. Bailey (Columbia U.);

A. Arrott (Virginia State University)

Figure 2: FMR line broadening measured in a Permalloy film

and calculated almost entirely from the microstructure of the

underlayer shown in the inset.

–0.60

–0.65

–0.70

–0.75

–0.80

–0.85

–0.90

Effective anisotropy (T)

0 0.1 0.2 0.3 0.4 0.5 0.6

Inverse permalloy thickness (nm–1)

Ag / Ni80Fe20 / Ag

Cu / Ni80Fe20 / Cu

Ta / Ni80Fe20 / Ta
40

Materials for Electronics

Platinum-iron group alloys have at least two

important potential applications: as a medium for

magnetic recording and as CO tolerant catalysts

in fuel cells. Alloy formation by electrodeposition

presents a convenient and inexpensive alternative

to conventional vacuum methods. A simple

thermodynamic model has been used to account

for the observed dependence of alloy composition

on the deposition potential.

Jonathan J. Mallett, William F. Egelhoff, Jr.,

and Thomas P. Moffat

Perhaps the most exciting application of iron-group

Pt alloys involves their high magnetic coercivity and

anisotropy in the L10 phase. This makes them ideal

candidates for future magnetic storage media, which

will require high coercivity material to sustain the

reductions in bit size needed to increase storage density.

Controlled alloy composition and microstructure are

essential for achieving the L10 phase, which requires

close to a 50:50 composition.

Iron-group Pt alloys may also find application

as poison-resistant hydrogen fuel cell catalysts.

A primary concern is the lifetime and efficiency of

the catalyst used to oxidize hydrogen gas in the cell.

Recent research suggests that replacing the traditional

Pt catalyst with a Pt alloy containing up to 15 %

of an Fe-group element can dramatically improve

the resistance of the catalyst to CO poisoning.

An inexpensive, reliable process for producing such

alloys is, therefore, likely to be of considerable utility

to fuel cell development.

An electrodeposition method has been developed

that allows smooth (< 5 nm RMS roughness) alloy

films to be deposited to a thickness of between 20 nm

and 3000 nm. Deposition takes place from a bath

containing 3 mM PtCl4 and 0.1 M of the reactive

metal ions (Fe2+, Ni2+, or Co2+). The deposition

potentials were chosen such that deposition of the

reactive metal in its bulk form would have been

energetically impossible. Platinum on the other hand

readily deposits at all of the chosen potentials. The

incorporation of the reactive metal occurs due to the

highly negative enthalpy of mixing of the alloy. This

reduces the activity of the reactive element in the alloy

and allows its deposition to occur at more positive

potentials than would be possible for the pure element.

The reactive ions are in much higher concentration than

the noble complexed platinum ions, which allows the

former to be reduced in a kinetically facile way that

enables equilibrium alloy compositions to be achieved.

Under these conditions, the alloy composition and

morphology was found to remain remarkably invariant

to significant perturbations in constituent concentrations.

The strong dependence of composition on potential is

shown in Figure 1 for three alloys.

Electrodeposited Pt1–x (Fe,Co,Ni)x Alloys

Figure 1: The theoretical (curves) and experimental (data points)

dependence of composition on potential.

Figure 2: The increase in coercivity on annealing.

Figure 2 shows the effect of annealing an FePt film

grown on a Cu(001) substrate. The transformation

to the L10 phase results in a dramatic increase in

magnetic coercivity. The 10 kOe coercivity produced

by the 650 oC anneal is suitable for next-generation

magnetic media.

Current activities are focused on extending

the investigation to ternary alloys and expanding

the available deposited structures to include

nanoparticles (useful as catalysts) and template-formed

nanostructures (for future magnetic recording media).

Contributors and Collaborators

E.B. Svedberg (Seagate Technology)
41

Materials for Electronics

Magnetic sensors play a central role in many

important technologies ranging from health care to

homeland security. A common need among these

technologies is greater sensitivity and smaller size.

In ultra-high density data storage, one of the most

pressing needs is for nano-structured media that store

data at ever-increasing densities. Improved methods

for the magnetic isolation of grains in ultra-thin films

are a key need; we have initiated research programs

in both areas.

William F. Egelhoff, Jr.

NIST’s Magnetic Engineering Research Facility

(MERF) is one of the most versatile facilities in the

world for the fabrication and analysis of novel magnetic

thin films. Two new areas of research, magnetic

sensors and magnetic media, illustrate this versatility.

The common link is that both require novel magnetic

thin films.

the correct composition for complex ultra-thin films.

MERF will soon become the only deposition system in

the world equipped for ultra-thin film deposition by IBSD,

AC and DC magnetron sputtering, and molecular beam

epitaxy. Such versatility will allow MERF to continue

to play a leading role in magnetic thin-film research.

In the area of novel magnetic media we have been

collaborating closely with Seagate. Seagate is the

world’s leading manufacturer of hard-disk drives, and

for the past two years, they have been sending a Ph.D.

physicist from their research labs to work with us,

first on ballistic magnetoresistance, and now on novel

magnetic media.

Novel Magnetic Materials for Sensors and

Ultra-High Density Data Storage

Figure 1: The Magnetic Engineering Research Facility (MERF).

It appears that ultra-sensitive magnetic sensors will

require the use of thin films of ultra-soft magnetic alloys.

These alloys often have a very complex composition such

as Fe73.5Si13.5B9Nb3Cu1 and require a very specific

annealing process. These materials are well-known in

bulk form but have never been produced in thin-film form.

The project goal is to carry out the metrology needed

to produce these materials as ultra-thin films.

We are presently modifying the MERF to add the

capability of ion-beam sputter deposition (IBSD). IBSD,

which is based on sputtering a target of the desired

composition, is the only reliable method for maintaining

Recent work determined a novel method for

magnetically decoupling grains in CoPd media. CoPd

multilayers are one of the leading candidates for the

next generation of magnetic media. We have found that

if a Au film is deposited on top of the CoPd and anneal

in air, two unexpected phenomena occur as a result of

rapid diffusion of atoms along grain boundaries. One is

that Co atoms diffuse to the surface, react with oxygen,

and remain at the surface. The other is that Au atoms

diffuse into the grain boundaries replacing Co. The net

effect is that the grain boundaries are demagnetized, and

each grain can magnetically switch independently of its

neighbors. This method provides the best magnetic

isolation of grains yet found.

Contributors and Collaborators

E.B. Svedberg, D. Weller (Seagate); R.D. McMichael,

T.P. Moffat, J. Mallett (Metallurgy Division, NIST);

D.P. Pappas (Electromagnetics Division, NIST)

Figure 2: Close collaborations with Seagate have contributed to

the success of this project.
Materials for Electronics

42

Magnetism is endemic to our society. Ferromagnets

are the basis for information storage in computers

and recording devices; they are found in all motors,

transformers, and generators; and they are used in

a host of other products like credit cards, cellular

telephones, radios, and televisions. However, the

magnetic characteristics of the ferromagnet used

in each of these applications varies with the

product. Consequently, industry needs to know

the interconnection between material characteristics

and magnetic properties, and how to control them.

A critical element in such an understanding is

knowledge of the fundamentals of spin interaction,

and how to measure it. NIST provides the metrology

needed by industry to do this.

Robert D. Shull and Jeffrey W. Lynn (NCNR)

I

n 1962, a new type of interaction between magnetic

 spins was predicted — a band structure effect caused

by an instability in the conduction electron gas near the

Fermi surface. The instability creates a new low-energy

state in which the magnetic spin orientations form a

standing wave, called a spin density wave (SDW).

Similarly, a wave of charge, called a charge density

wave (CDW), was also predicted. Charge density waves

have since been found experimentally, and the SDW

concept has been successfully used to explain the unusual

incommensurate antiferromagnetism in Cr. However,

evidence for SDWs in a ferromagnet has proven elusive.

Using neutron diffraction measurements at NIST,

we recently discovered a SDW in a single crystal of

Fe60Al40, a material with ferromagnetically interacting

spins. This was shown (Figure 1) by the presence of

scattering intensity at locations where there was no

atomic reciprocal lattice vector (i.e., at places where

there would normally be no coherent atomic scattering).

In fact, the data showed there are several SDWs in

the material with wave vectors near (110) directions

(shown in Figure 2). No such waves were found

along either (100) or (111) directions.

Discovery of Spin Density Waves in a Ferromagnet: Fe-Al

Figure 1: Neutron scattering intensity for a) polycrystalline

Fe60Al40 at 120 K and 1.7 K with their difference in the inset and

b) single crystal Fe60Al40 at 12 K shown as contours about the

(1/7, 1/7, 1/7) peak.

Figure 2: The reciprocal lattice spots in Fe60Al40, showing the

SDW wave vectors (black arrows) (Physical Review Letters 91,

217201-1 (2004).

The presence of SDWs shows the exchange

interactions between magnetic spins in Fe-Al is a band

structure (i.e., non-local) effect and explains the large

magnetism in these materials containing a large content

of “non-magnetic” atoms. This discovery should be as

important to the understanding of magnetism in metals as

the SDWs in Cr. In Cr, the SDW wave vector, close to a

(100) direction, makes moments of nearest neighbors in

the bcc structure almost oppositely aligned.

Contributors and Collaborators

A.S. Arrott (Virginia State University); D.R. Noakes

(Virginia State University); M.G. Belk (Virginia State

University); S.C. Deevi (Phillip Morris Co.); D. Wu

(Dartmouth College)
Program Overview

Safety and Reliability

While various structural failures have captured

national attention over the years, the events of

September 11, 2001 generated a greatly increased

awareness of vulnerabilities in our national

infrastructure. The extent of these vulnerabilities

depends to a large degree on the performance of

materials in situations outside of the original design

considerations. It is now recognized that a critical

and urgent national need exists to establish the

behavior of materials under such extreme loadings,

and to disseminate guidance and tools to assess and

reduce future vulnerabilities.

The goal of providing a technical basis for cost-effective

changes to national practices and standards, coupled with

a need for an integrated effort drawing on capabilities and

expertise of a broad collaborative team, has lead to the

development of the Safety and Reliability Program within

MSEL. This program draws on the expertise of several

divisions in MSEL and across NIST.

Project selection is guided by an identification and

assessment of the particular vulnerabilities within our

materials-based infrastructure, and focusing on those

issues which would benefit strongly by improved

measurements, standards, and materials data. Ultimately,

we intend to moderate the effects of acts of terrorism,

natural disasters, or other emergencies, all through

improved use of materials.

Our vision is to be the key resource within the Federal

Government for materials metrology development as

realized through the following objectives:

■ Identify and address vulnerabilities and needed

improvements in U.S. infrastructure;

■ Develop and deliver standard measurements and data;

■ Develop advanced measurement methods needed by

industry to address new problems that arise with the

development of new materials;

■ Support other agency needs for materials expertise.

This program responds both to customer requests

(primarily other government agencies) and to the

Department of Commerce 2005 Strategic Goal of

“providing the information and framework to enable

the economy to operate efficiently and equitably.”

For example, engineering design can produce safe and

reliable structures only when the property data for the

materials is available and accurate. Equally important,

manufacturers and their suppliers need to agree on

how material properties should be measured.

The Safety and Reliability Program works toward

solutions to measurement problems on scales ranging

from the macro to the micro, in three of the Laboratory’s

Divisions (Materials Reliability, Metallurgy, and Polymers).

The scope of activities includes the development and

innovative use of state-of-the-art measurement systems;

leadership in the development of standardized test

procedures and traceability protocols; development of

an understanding of materials in novel conditions; and

development and certification of Standard Reference

Materials (SRMs). Many of the tests involve extreme

conditions, such as high rates of loading, high temperatures,

or unusual environments (e.g., deep underwater). These

extreme conditions often produce physical and mechanical

properties that differ significantly from the handbook

values for their bulk properties under traditional conditions.

These objectives will be realized through innovative

materials, property measurement and modeling.

The MSEL Safety and Reliability Program is

also contributing to the development of test method

standards through committee leadership roles in

standards development organizations such as the

ASTM International and the International Standards

Organization (ISO). In many cases, industry also

depends on measurements that can be traced to NIST

Standard Reference Materials (SRM®).

In addition to the activities above, all three divisions

provide assistance to various government agencies on

homeland security and infrastructural issues. Projects

include assessing the performance of structural steels

as part of the NIST World Trade Center Investigation,

advising the Bureau of Reclamation on metallurgical issues

involving pipelines and dams, advising the Department of

the Interior on the structural integrity of the U.S.S. Arizona

Memorial, and collaborating with both the Department

of Transportation and the Department of Energy on

pipeline safety issues.

Contact: Frank W. Gayle (Metallurgy Division)

43
44

Safety and Reliability

Analysis of Structural Steel in the World Trade Center

In 2002 NIST became the lead agency in the

investigation of the World Trade Center collapse.

The investigation addresses many aspects of the

catastrophe, from occupant egress to factors

affecting how long the Twin Towers stood after being

hit by the airplanes, with a goal of gaining valuable

information for the future. A critical aspect of

the investigation is the metallurgical analysis of

structural steels from the Twin Towers. The analysis

includes characterization of properties, failure

modes, and temperature excursions seen by the steel.

Stephen W. Banovic, Richard J. Fields,

Timothy J. Foecke, William E. Luecke,

J. David McColskey, Christopher N. McCowan,

Thomas A. Siewert, and Frank W. Gayle

The collapse of the World Trade Center (WTC)

Towers on September 11, 2001, was the worst building

disaster in human history. Engineers, emergency

responders, and the nation were largely unprepared for

such a catastrophe. NIST is investigating the disaster

(see http://wtc.nist.gov/), and a primary objective is to

determine why and how the towers collapsed after the

initial impact of the aircraft. As part of this investigation,

the Metallurgy and Materials Reliability Divisions in

MSEL are studying recovered structural steel from

the WTC site. Progress in this study is outlined here.

Task 1 — Collect and catalog physical evidence:

236 structural pieces of the WTC towers have

been collected, brought to NIST and studied. Reports

have been issued documenting the steel, the as-built

locations, the structure of the towers based on design

documents, and the standards at the time of construction.

Figure 1: Enhanced image of the impact zone of WTC 2 has

allowed determination of failure modes in the perimeter columns.

Figure 2: Normalized yield strength and ultimate tensile strength

measured as function of temperature. Model curve is based on

historical data for WTC era steels.

Task 2 — Categorize failure mechanisms

based on visual evidence: Available photographic

evidence and recovered steel have been examined and

documented as to failure mechanisms (Figure 1).

Task 3 — Determine steel properties to

support structure performance and airplane

impact modeling studies: 29 different steels

have been characterized for room temperature

mechanical properties. High-temperature and

high-strain-rate tests are now complete. Creep, or

time–temperature-dependent behavior, has been

determined for floor truss and column steel.

Task 4 — Correlate determined steel properties

with specified properties: Most steel was found to

exceed the specified minimum values by 5 to 10 percent.

Task 5 — Analyze steel to estimate temperature

extremes: We have developed a technique of

paint characterization to provide a quick mapping of

temperature excursions seen by the steel. Challenges

included deciphering pre- and post-collapse exposure

(see related Highlight in this report).

Data on material properties have been provided to aid

in the modeling of plane impact and structural response

to the fires. A final draft of the investigation report will

be released for public comment in December 2004.

Contributors and Collaborators

R. Santoyo, L. Rodine (Materials Reliability Division,

MSEL, NIST); M. Williams, S. Claggett, M. Iadicola,

R. Jiggetts (Metallurgy Division, MSEL, NIST)
45

Safety and Reliability

Standard Test Methods for Fire-Resistant Steel

The fires in the World Trade Center and the

ensuing collapse focused attention on the

vulnerability of structural steel to fire. Recently,

steel mills in Europe and Japan have begun to

market steels designated as “fire-resistant.”

This project is developing a standard test method

for quantitatively evaluating and comparing

the resistance to high-temperature deformation

and failure of structural steels.

William E. Luecke, J. David McColskey,

Richard J. Fields, and Frank W. Gayle

At room temperature, the stress–strain behavior of

 structural steel is considered to be independent of

time. Above about 300 °C, structural steel begins to lose

strength. At still higher temperatures, about 500 °C,

creep, or time-dependent deformation, further reduces

the load-carrying capability. By 600 °C, most structural

steels have lost more than half their strength. For this

reason, structural steels in buildings are insulated to

minimize the temperature rise and resulting strength loss.

Fire resistant (FR) steels are intended to be drop-in

replacements for structural steel. They typically meet

the same specifications with similar welding properties

and cost only marginally more. Yet these steels retain

superior high-temperature strength, offering potential

for extra time for building occupants to escape a fire.

In Japan and Europe, FR steels are qualified

based on yield strength retention at high temperature.

This definition may not be the most appropriate since

retained yield strength is a short-time property, yet

fire-resistance is often measured in hours. Also, with

increasing temperature, strength becomes increasingly

sensitive to the strain rate. Current U.S. standards for

load-bearing components in fire are based on time to

reach a given temperature, so effectively all steels are

considered to have the same high-temperature strength

reduction, regardless of actual properties.

We are currently studying a hybrid of creep and

conventional tension tests. The test specimen is held

under constant load as the test temperature ramps

upward linearly. Over a narrow temperature range,

which can be approximated as a critical temperature,

the deformation rate increases dramatically, and the

specimen fails. This critical temperature can be used

as a measure of fire resistance.

One goal of this project is to refine this test

technique and offer it as a draft standard. Published

research has established that the temperature ramp test

Figure 1: Comparison of “run-away creep” deformation of

FR and ordinary construction steel.

can rank steels, but definitive studies comparing

ordinary and FR steels are lacking. Until a standard

test method is developed, it is difficult to confidently

compare results between laboratories. This research

will focus on understanding the limitations, repeatability,

and reproducibility of the method by characterizing

several different classes of construction steels.

Interlaboratory studies will be used to probe the

method’s limitations, precision and bias.

A second goal is to generate constitutive models

for modeling high-temperature deformation of steels.

If test results are not predictable from underlying

deformation behavior, a test cannot possibly indicate

real-world performance. A second benefit is that

much-needed data will be supplied for finite element

modeling of modern structural steel deformation in fire,

a prerequisite for performance-based fire resistant design.

Figure 1 illustrates the concept of critical

temperature for “run-away” creep for two FR steels

and one conventional construction steel. The results

demonstrate the potential performance advantage of

FR steel. Much more work is necessary, however, to

understand the variability in performance of ordinary

and FR steels.

During 2004, we also spearheaded the development

of an ASTM task group under committee A01 to evaluate

test methods for fire resistance of structural steel.

Contributors and Collaborators

M. Bykowski (SURF)
46

Safety and Reliability

Pipeline Safety: Corrosion, Fracture, and Fatigue

A critical element of the nation’s infrastructure is

the more than 2 million miles of natural gas and

hazardous liquid pipelines that provide over half

of the nation’s energy. While pipelines are the

safest means of transporting these materials, they

are not immune to failures. In 2002, Congress

passed the Pipeline Safety Improvement Act to

reduce pipeline failure rates, increase public

safety, and ensure a continuous and uninterrupted

delivery of the nation’s energy supply. NIST is

working with the pipeline industry, DoT, and DoE

to provide the measurement methods, standards,

and data needed to accomplish this objective.

Richard E. Ricker

I

n December 2002, Congress passed the Pipeline

 Safety Improvement Act (PSIA), through which

the DoT Office of Pipeline Safety (DoT/OPS), DoE,

and NIST will coordinate pipeline R&D. In FY 2004,

DoT/OPS, DoE, and NIST signed a memorandum

of understanding (MOU) and a Five-Year Joint R&D

Plan detailing agency responsibilities in a program

of research, development, demonstration, and

standardization for pipeline integrity. The Department

of the Interior/MMS has also been included in the

plan because of its responsibility for off-shore oil

pipelines. Under these agreements, NIST is responsible

for materials research, fire safety, and standards

development that pertain to pipeline safety, reliability,

and damage prevention.

A number of factors have combined to increase the

need for improvements in the safe operation of pipelines.

Among these are increases in national energy needs,

population densities near pipelines, environmental

concerns, and average pipeline age. While recent accidents

have brought increased attention to this issue, pipeline

incident rates have not changed significantly since 1986

(Figure 1). While failure mechanisms are not always

thoroughly documented, the DoT/OPS incident data can

be used to estimate the distribution of failure mechanisms

(Figure 2). Clearly, fracture, fatigue and corrosion account

for a significant proportion of the failures. Understanding

and developing better standards for preventing these

materials-related failure mechanisms is the objective

of NIST R&D in 2004–2005 project.

Figure 1: Pipeline incidents and damage since 1986 (DoT/OPS).

Figure 2: Estimated pipeline failure mechanism distribution

based on DoT/OPS data over ≈ 10 years.

NIST has a history of contributions to pipeline safety.

For example, NIST conducted welding and fracture

research for the Alaskan pipeline, and the NIST 14-year

study of underground corrosion is the basis for several

current pipeline standards. The current program will

review existing standards, the current corrosion, fatigue,

and fracture issues, and evaluate where improvements

may be possible. This work will be done in collaboration

with industry, particularly the Pipeline Research Council

International (PRCI) Corrosion and Inspection Technical

Committee, and with private sector consensus standards

setting organizations. NIST and its collaborators

have discussed and reviewed NIST R&D plans and

coordination. A Government/Industry Pipeline

R&D Forum is being organized for April 2005 to

present the Five-Year Joint R&D Plan.

Contributors and Collaborators

R.J. Fields, T.J. Foecke, F.W. Gayle,

C.A. Handwerker (Metallurgy Division, NIST);

T. Siewert, C. McCowan (Materials Reliability Division,

NIST); C. Sames (PRCI); J. Merritt, S. Gerard,

R. Smith (DoT/OPS); C. Freitas, R. Anderson,

D. Driscoll (DoE); M. Else (DoI)
47

Frangible Bullets and Soft Body Armor

Safety and Reliability

Police officers’ lives often depend upon the

effectiveness of their soft body armor. Continued

introduction of new types of body armor and

bullets (including lead-free frangible models) are

overwhelming the enforcement community’s ability

to test everything adequately. At the request of

the Office for Law Enforcement Standards (OLES),

we are conducting a thorough study to identify

the determining factors for effective protection

against the various types of bullets on the market.

Lyle E. Levine and Richard Rhorer (822)

The impact of a bullet on soft body armor is a

remarkably complex process involving complex

geometries (including the density and weave pattern of

the body armor fibers) and high-strain-rate properties

of the bullet and armor materials. Complicating the

issue further, recent lead-free bullet designs are being

produced with a wide range of materials (copper, tin,

iron, tungsten, zinc and polymers) and processing

conditions (sintering, cold-pressing and injection

molding). The mechanical behavior of these new bullet

designs can be dramatically different from those of the

conventional lead bullets for which soft body armor has

been designed. Degradation of body armor materials

with age, mechanical wear and exposure conditions

(moisture and light) is also important. A long-term,

comprehensive project to address all of these issues

was started this fiscal year.

Planned tasks for bullets include:

■ High-strain-rate testing of bullets (longitudinal and

diametral) and bullet materials using the NIST Kolsky

bar facility. Approximately 600 tests will be required.

■ Corresponding low-strain-rate testing using a

conventional mechanical testing machine.

■ Metallographic and chemical analyses of bullet

materials.

Planned tasks for soft body armor materials include:

■ Design and construction of a miniature Kolsky bar

for high-strain-rate testing of fibers.

■ Design and construction of tensile cages for

miniature and existing Kolsky bars.

■ Exposure of fiber test samples to degrading

conditions (light, moisture and abrasion)

■ High-strain rate testing of as-received and degraded

individual fibers, multiple non-braided fibers, and

braided fiber bundles. Approximately 2000 tests

will be required.

■ Corresponding low-strain-rate testing using a

conventional mechanical testing machine.

These tasks will be complemented by finite element

modeling of:

■ High-strain-rate bullet tests using measured

high-strain-rate behavior of bullet materials.

■ Fiber and fiber bundle tests using measured

high-strain-rate behavior of fiber materials.

■ Bullet impacts with woven body armor fabric.

Expected Impacts

The test data will be used by the U.S. Department of

Justice to determine what actions are required to ensure

that soft body armor provides adequate protection to

police officers in the field. The experimentally validated

finite element models will be used to screen combinations

of bullets and body armor designs to identify potential

threats at an early stage.

Contributors and Collaborators

S. Banovic, R. Fields, L. Ma, S. Mates

(Metallurgy Division, NIST); M. Kennedy, E. Whitenton

(Manufacturing Metrology Division, NIST); T. Burns

(Mathematical and Computational Sciences Division,

NIST)

Figure 1: Frangible 9 mm bullet and remains after impact.
48

Safety and Reliability

Marine Forensics and Preservation of Historic Shipwrecks

Historic shipwrecks are valuable cultural

resources continuously under attack by their

environment. Preservation techniques aimed at

slowing corrosion processes and mechanically

stabilizing shipwreck structures are being modeled

and designed in coordination with the National

Park Service, NOAA, and the U.S. Navy. These

techniques are being applied to such wreck sites

as the USS Arizona, the Ellis Island Ferry, RMS

Titanic, CSS Hunley, and the USS Monitor.

Tim Foecke

Since the attack on Pearl Harbor on December 7th,

1941, the wreck of the USS Arizona has been

slowly corroding and collapsing. The monument that

straddles the wreck sees over 700,000 visitors per year,

and there is immense interest in preserving the wreck

for as long as possible. Aside from the historical

interest, there are substantial environmental risks

associated with any large-scale collapse of the wreck,

as there is still an estimated 500,000 gallons of fuel oil

trapped below water.

The Submerged Cultural Resources Unit (SCRU) of

the National Park Service (NPS) has responsibility for

maintaining and preserving the wreck. Based on our

past experience in marine forensics, SCRU approached

the Metallurgy Division for assistance in several areas.

Figure 1: Finite element model of the center section of the

USS Arizona, where fuel oil is believed to be concentrated.

Advice is being given on methods to measure the

remaining thickness of the hull through the existing

bioencrustation. A finite element model (Figure 1) is

under construction, and techniques are being developed

to map the corrosion current data gathered by the NPS

over the last 20 years onto the model in the form of

decreasing plate thicknesses.

The tools developed in this project will eventually

be transferred to companies and organizations that

are responsible for monitoring submerged wrecks

containing hazardous materials, allowing them to

better simulate critical conditions.

Figure 2: Cross-section of a rivet extracted from the submarine

HL Hunley, showing slag flow lines on the left. The submarine, the

first to sink an enemy ship, is currently on shore in Charleston, SC).

In addition to the USS Arizona, we are providing

assistance and technical expertise to NPS, NOAA and

the Navy regarding preservation of the Ellis Island

Ferry, the CSS Hunley (Figure 2), the USS Monitor

(partially salvaged), and the RMS Titanic. NIST

participated in a multi-agency remote survey of the

Titanic wreck in June 2004 at the University of Rhode

Island, satellite linked to the NOAA Ship Ron Brown.

Ongoing analysis of the photos and videos taken during

this expedition will attempt to map the degradation of

the wreck and chart the impact of any human visits.

Contributors and Collaborators

L. Ma, S. Banovic (Metallurgy Division, NIST);

L. Murphy, M. Russell, D. Conlin (Submerged Cultural

Resources Unit, National Park Service); Lt. J. Weirich

(NOAA); Cdr. J. Morganthou (CINCPAC, U.S. Navy)
49

Safety and Reliability

Kinetic Penetrators and Amorphous Metals

Environmental and political debate on the

continued use of depleted uranium (DU) alloys

has led to increased efforts at developing low-cost,

reduced-toxicity replacement penetrator materials

with similar ballistic performance. The Metallurgy

Division has been working with the Army Research

Laboratory (ARL) on a novel tungsten-amorphous

metal composite material as one of these new

DU alloy replacements. The project relies on

the Metallurgy Division’s expertise in rapid

solidification processing and instrumented

powder consolidation to provide these composite

materials to the ARL for ballistic testing.

Stephen D. Ridder

Bulk amorphous metal (BAM) alloys are a relatively

new class of alloys that solidify amorphously in

castings with cross-sections as large as 10 mm

across, a significant improvement over the sub-1 mm

castings of conventional amorphous metal alloys.

The Army’s interest in high-density BAM alloys is a

result of their need for a new armor-piercing projectile

material to replace the current Depleted Uranium

technology.

Modern, tank-fired armor-piercing munitions are

high-velocity projectiles machined from DU alloys or

from two-phase, tungsten-based heavy alloy (W–)

composites. High-density materials are chosen to

maximize the kinetic energy available for armor

penetration. The projectile material is partially

consumed by erosion or back extrusion as it enters

armor plate. Current DU alloys are superior to available

W-composites due to “continuous tip sharpening”

compared to the tip blunting and “mushrooming”

seen in the W-composites. This tip sharpening is

generally attributed to adiabatic shear localization

(ASL) and failure, a specific failure mode exhibited

by DU alloys when rapidly loaded. Heat generated

within the penetrator during high-strain-rate loading

produces sufficient thermal softening of the DU alloy

structure to overcome work-hardening in ASL bands

concentrated near the tip of the penetrator that

promotes rapid removal of deformed material.

The continuously sharpened penetrator concentrates

the remaining kinetic energy at the end of a relatively

narrow tunnel, thus reducing energy loss and

improving penetrator efficiency.

Recent work by the ARL has shown that

BAM alloys have promise in providing the necessary

The Metallurgy Division designed and

built a small-scale gas atomizer to study the

composition-dependent solidification behavior of

BAM alloys using small batch (250 g) processing

to reduce material and processing costs. Figure 1

shows spherical amorphous Hf alloy powder

particles recently produced. The material produced

by this device is preferred to the more readily

available comminuted melt-spun amorphous ribbon

material because these spherical particles can be

blended with tungsten powder and consolidated to

produce a more homogeneous W-composite billet.

A hot isostatic press (HIP) has been instrumented

with an eddy current sensor developed at NIST to

follow the composite consolidation and provide the

necessary quantitative, real-time monitoring of the

progress of densification. This technology will

allow full densification of the W-composite without

inducing large-scale crystallization of the Hf based

BAM powder.

Contributors and Collaborators

F.S. Biancaniello, C.E. Campbell, R.J. Fields,

R.D. Jiggetts, U.R. Kattner, S.P. Mates (NIST),

L. Kecskes (U.S. Army)

Figure 1: Amorphous Hf alloy powder particles produced in

NIST small-scale gas atomization facility.

ASL-like behavior that could lead to a W-composite

penetrator material with performance similar to

DU alloys.
50
51

Metallurgy Division FY04 Annual Report Publication List

Metallurgy Division FY04 Annual Report Publication List

Anelasticity and Springback Prediction

Ma, L., T.F. Zahrah, and R.J. Fields, “Numerical

three dimensional simulation of cold compaction and

springback for particulate prealloyed reinforced

composites,” Powder Metallurgy Journal 47 (1),

31–36, 2004.

Munitz, A., D. Dayan, D.J. Pitchure, and

R.E. Ricker, “Dynamic mechanical analysis of pure

Mg and Mg AZ31 alloy,” Magnesium Technology 2004,

edited by A.A. Lu, TMS, 2004.

Paul, R.L., H. Chen–Mayer, G.R. Myneni,

W.A. Lanford, and R.E. Ricker, “Hydrogen uptake

by high purity niobium studied by nuclear analytical

methods,” Matériaux and Techniques 91 (7-8-9),

23–27, 2003.

Microstructural Origins of

Surface Roughening and Strain Localization

Liu, J., S.W. Banovic, F.S. Biancaniello, and

R.D. Jiggetts, “Through-thickness texture

inhomogeneity in a recrystallized Al-Mg alloy,”

Met. Trans. A Communications, (submitted), 2004.

Liu, J., and J.G. Morris, “Recrystalliation

microstructures and textures in AA 5052 continuous

cast and direct chill cast aluminum alloy,” Materials

Science Eng A, (submitted), 2004.

Stoudt, M.R., S.W. Banovic, and T. Quarrick,

“Evolution of deformation-induced surface

morphologies developed on Fe-based sheet metal,”

45th MWSP Conference Proceedings, edited by

M.A. Baker, Warrendale, PA: Iron and Steel Society,

pp. 507–517, 2003.

Stoudt, M.R., J.B. Hubbard, and S.W. Banovic,

“Evolution of deformation induced surface

morphologies generated in Fe-based sheet,”

Test and Measurement World, (submitted), 2004.

Stoudt, M.R., J.B. Hubbard, and S.W. Banovic,

“Evolution of deformation induced surface

morphologies generate in Fe-based sheet,” Special

Publication # 1837; Innovations in Modeling and

Testing of Steel Structures for Automotive Applications,

edited by R. Mohan, et al., Warrendale, PA: SAE, 2004.

Stoudt, M.R., J.B. Hubbard, and S.W. Banovic,

“Evolution of deformation induced surface

morphologies generated in Fe-based sheet,”

Transactions of the SAE, (submitted), 2004.

Stoudt, M.R., J.B. Hubbard, and S.W. Banovic,

“Evolution of deformation induced surface

morphologies generated in Fe-based sheet,”

SAE Transactions: Journal of Materials and

Manufacturing, (in press), 2004.

Stoudt, M.R., A. Munitz, S.W. Banovic, and

R.J. Fields, “Effect of uniaxial strain on the surface

roughness of pure Mg and Mg AZ31 alloy,”

Magnesium 2004, (submitted), 2004.

Stoudt, M.R., A. Munitz, S.W. Banovic, and

R.J. Fields, “Effect of uniaxial strain on the surface

roughness of pure Mg and Mg AZ31 alloy,” Magnesium

Technology 2004, edited by A.A. Luo, Warrendale, PA:

TMS, pp. 269–274, 2004.

Underlying Processes of

Plastic Deformation in Metal Alloys

Cai, M., S.C. Langford, L.E. Levine, and

J.T. Dickinson, “Determination of strain localization

in aluminum alloys using laser-induced photoelectron

emission,” Journal of Applied Physics, (submitted),

2004.

Delos–Reyes, M.A., M.E. Kassner, and L.E. Levine,

“X-ray diffraction and the existence of long range

internal stresses,” Dislocations, Plasticity and Metal

Forming, edited by A.S. Khan, R. Kazmi, and J. Zhou,

Fulton, MD: Neat Press, p. 262, 2003.

Khan, S.M, H.M. Zbib, and D.A. Hughes,

“Multi-scale dislocation dynamics plasticity: application

for Frank’s dislocation boundaries,” (submitted), 2004.

Kramer, D.E., M.F. Savage, and L.E. Levine,

“AFM observations of slip band development in Al

single crystals,” Acta Materialia, (submitted), 2004.

Levine, L.E., “Multiscale phenomena in materials —

experiments and modeling related to mechanical

behavior,” Symposium Proceedings Vol. 779, edited by

H.M. Zbib, D.H. Lassila, L.E. Levine, and K.J. Hemker,

Warrendale, PA: MRS, 2003.

Levine, L.E., and R.M. Thomson, “A statistical

connection between dislocations and mechanical

properties,” Dislocations, Plasticity and Metal

Forming, edited by A.S. Khan, R. Kazmi, and J. Zhou,

Fulton, MD: Neat Press, p. 286, 2003.

Tavazza, F., L.E. Levine, and A. Chaka, “Atomistic

insights into dislocation dynamics in metal forming,”

Proceedings of 3rd International Computational

Modeling and Simulation of Materials, Acireale, Italy,

(in press), 2004.
52

Metallurgy Division FY04 Annual Report Publication List

High Speed Machining

Basak, D., H.W. Yoon, R. Rhorer, T.J. Burns, and

T. Matsumoto, “Temperature control of pulse heated

specimens in a Kolsky bar apparatus using microsecond

time-resolved pyrometry,” International Journal of

Thermophysics, 25 (2), 561–574, 2004.

Basak, D., H.W. Yoon, R. Rhorer, and T.J. Burns,

“Microsecond time-resolved pyrometry during

rapid resistive heating of samples in a Kolsky bar

apparatus,” American Institute of Physics, 684, Part 2,

pp. 753–757, 2003.

Burns, T., M. Davies, R. Rhorer, D. Basak,

H. Yoon, R.J. Fields, L.E. Levine, E. Whitenton,

M. Kennedy, and R. Ivester, “Influence of heating rate

of flow stress in modeling of machining processes,”

Proceedings of the CIRP International Workshop on

Modeling and Machining, Cluny, France, (in press),

May 2004.

Mechanisms for Delivery of

Thermodynamic and Kinetic Data

Campbell, C.E., W.J. Boettinger, T. Hansen,

P. Merewether, and B.A. Mueller, “Examination of

multicomponent diffusion between two Ni-base

superalloys,” Properties of Complex Inorganic Solids 3,

edited by P. Turchi, et al., New York: Kluwer

Academics/Plenum Publishers, (in press), 2003.

Campbell, C.E., J.C. Zhao, and M.F. Henry,

“Comparison of experimental and simulated

multicomponent Ni-base superalloy diffusion couples,”

Journal of Phase Equilibria and Diffusion, 25 (1),

6–15, 2004.

Kattner, U.R., J.E. Morral, and W.J. Boettinger,

“Databases for computational thermodynamics and

diffusion modeling,” Journal of Phase Equilibria and

Diffusion, 24 (3), 416–421, 2003.

Phase Field Modeling Tools for

Microstructure and Stress Evolution

Alikakos, N.D., P.W. Bates, J.W. Cahn, P.C. Fife,

G. Fusco, and G.B. Tangoglu, “Extreme Anisotropy of

Diffusion Interfaces in Crystals,” SIAM Journal of

Applied Mathematics, (in press), 2003.

Cahn, J.W., and J. Taylor, “A unified approach

to motion of grain boundaries, relative tangential

translation along grain boundaries, and grain rotation,”

Acta Materialia, (in press), 2003.

Granasy, L., T. Pusztai, T. Borzsonyi, J.A. Warren,

and J.F. Douglas, “A general mechanism of

polycrystalline growth,” Nature Materials, (in press),

2004.

Granasy, L., T. Pusztai, G. Tegze, J.A. Warren,

and J.F. Douglas, “On the growth and form of

spherulites,” NATURE, (submitted), 2004.

Granasy, L., T. Pusztai, and J.A. Warren,

“Modelling polycrystalline solidification using phase

field theory,” Journal of Physics: Condensed Matter,

(in press), 2004.

Guyer, J.E., W.J. Boettinger, J.A. Warren,

and G.B. McFadden, “Phase Field Modeling of

Electrochemistry I: Equilibrium,” Physical Review E,

69 (2) Art. No. 021603, Part 1, February 2004.

Guyer, J.E., W.J. Boettinger, J.A. Warren,

and G.B. McFadden, “Phase Field Modeling of

Electrochemistry II: Kinetics,” Physical Review E,

62 (2), Art. No. 02164, 2004.

Guyer, J.E., D. Wheeler, and J.A. Warren,

“A finite volume PDE solver using Python (FlPy),”

http://www.python.org/dc2004/papers/28,

WEB Publication, (submitted), 2004.

Lewis, D.J., T. Puztai, L. Granasy, J.A. Warren,

and W.J. Boettinger, “Phase field models for eutectic

solidification,” Journal of Materials, 56 (4), 34–39,

April 2004.

Sekerka, R.F., and J.W. Cahn, “Solid–liquid

equilibrium for non-hydrostatic stress,” Acta

Materialia, (submitted), 2003.

Tegze, G., J.A. Warren, L. Granasy, T. Puztai,

T. Borzsonyi, and J.F. Douglas, “The influence of

foreign particles in the formation of polycrystalline

solidification patterns,” Solidification Processes and

Microstructures: A Symposium in Honor of Prof.

W. Kurz, M. Rappaz, C. Beckermann, and R. Trivedi,

TMS, pp. 379–385, 2004.

Upmanyu, M., D.J. Srolovitz, A.E. Lobkovsky,

J.A. Warren, and W.C. Carter, “Simultaneous grain

boundary migration and grain rotation,” Acta

Materialia, (submitted), 2003.

Warren, J.A., R. Kobayashi, A.E. Lobkovsky,

and W.C. Carter, “Extending phase field models of

polycrystalline materials,” Acta Materialia, 51,

6035–6058, 2003.

Warren, J.A., L. Loginova, L. Granasy,

T. Borzsonyi, and T. Pusztai, “Phase field modeling

of alloy polycrystals,” Proceedings for Modeling

Casting and Advanced Solidification Processes X,

edited by D. Stefanescu, J.A. Warren, M. Krane,

and M. Jolly, p. 45–52, 2003.
53

Metallurgy Division FY04 Annual Report Publication List

Hardness Standardization — Rockwell,

Vickers, Knoop

Ma, L., S. Low, and J. Fink, “Effect of steel and

tungsten carbid ball indenters on Rockwell hardness

tests,” Proceedings of HARDMEKO, (submitted), 2004.

Stibler, A., S.R. Low, and R. Ellis, “Comparative

measurements of Slovenian and USA Rockwell C

hardness scales,” Hardmeko 2004, (submitted), 2004.

3D Electron Microscopy

Ford, A.X., J.E. Bonevich, R.D. McMichael,

M.D. Vaudin, and T.P. Moffat, “Structure and magnetic

properties of electrodeposited Co on n-GaAs(001),”

Journal of Electrochemical Society, Vol. 150, Issue 11,

pp. C753–759, September 2004.

Lehman, S.Y., A. Roshko, R.P. Mirin, and

J.E. Bonevich, “Investigation of the shape of InGaAs/

GaAs quantum dots,” Proceedings of Materials

Research Society, Vol. 737, 2003, (in press).

Nanostructure Fabrication Processes:

Electrochemical Processing of Nanowires

Kongstein, O., U. Bertocci, and G.R. Stafford,

“In situ stress measurements during copper

electrodeposition on (111)-textured Au,” (submitted),

2004.

Wheeler, D., T.P. Moffat, G.B. McFadden,

S.R. Coriell, and D. Josell, “Influence of a catalytic

surfactant on roughness evolution during film growth,”

Journal of Electrochemical Society, 151 (8),

C538–544, July 2004.

USAXS Imaging of Biomaterials

Levine, L.E., and G.G. Long, “X-ray imaging

with ultra-small-angle x-ray scattering as a contrast

mechanism,” Journal of Applied Crystallography,

(in press), 2004.

Measurements for Compound

Semiconductors

Davydov, A.V., L.A. Bendersky, W.J. Boettinger,

D. Josell, M.D. Vaudin, C.S. Chang, and I. Takeuchi,

“Combinatorial investigation of structural quality of

Au/Ni contacts on GaN,” Applied Surface Science

Journal 223 (1–3), 24–29, 2004.

Lu, C.J., L.A. Bendersky, H. Lu, and W.J. Schaff,

“Suppression of threading dislocations in InN thin films

grown on (0001) sapphire with a GaN buffer layer,”

Applied Physics Letters 83, 2817, 2003.

Lu, C.J., A.V. Davydov, D. Josell, and

L.A. Bendersky, “Interfacial reactions of Ti/n-GaN

contacts at elevated temperature,” Journal of Applied

Physic, Vol. 94, No. 1, pp. 245–253, 2003.

Schenck, P., D.L. Kaiser, and A.V. Davydov,

“High-throughput characterization of the optical

properties of compositionally graded combinatorial

films,” Applied Surface Science Journal, 223 (1-3),

200, 2004.

Pb-free Surface Finishes: Sn Whisker Growth

Bogustavsky, I., P. Bush, E. Kam–Lum, M. Kwoka,

J. McCullen, K. Spalding, K. Vo, and M.E. Williams,

“NEMI tin whisker test method standards,” SMTAI

Proceedings, (submitted), 2003.

Pb-free Solder: Manufacturability and

Reliability

Allen, S.L., M.R. Notis, R.R. Chromik, R.P. Vinci,

D.J. Lewis, and R.J. Schaefer, “Microstructural

evolution in lead-free solder alloy Part II: directionally

solidified eutectic tin–silver–copper, tin–copper and

tin–silver alloys,” Journal of Materials Research,

(submitted), 2004.

Bertocci, U., “An EQMB examination of Cu surface

oxides in borate buffer,” Electrochemica Acta 49,

1831–1841, 2004.

Handwerker, Carol, Jasbir Bath, Elizabeth

Bennedetto, Edwin Bradley, Ron Gedney, Tom Siewert,

Polina Snugovsky, and John Sohn, NEMI Lead-Free

Assembly Project: Comparison Between PbSn and

SnAgCu Reliability and Microstructures, Benedetto,

Proceedings of Surface Mount Technology

International, Chicago, 2003.

Handwerker, C.A., U.R. Kattner, and K.-W. Moon,

“Materials Science Concepts in Lead-Free Soldering,”

Pb-Free Solders, edited by K. Suganuma, Marcel

Dekker, 2004.

Handwerker, C.A., E.E. deKluizenaar, K. Suganuma,

and F.G. Gayle, “Major International Lead (Pb)-Free

Solder Studies,” Handbook of Lead-Free Solder

Technology for Microelectronic Assemblies, edited

by K. Puttlitz and K. Stalter, McGraw Hill/IEEE,

pp. 665–728, 2004.

Moon, K., and W.J. Boettinger, “Difficulties in

determining eutectic compositions: the Sn-Ag-Cu

ternary eutectic,” JOM 56 (4), 22–27, 2004.
54

Metallurgy Division FY04 Annual Report Publication List

Rae, A., and C.A. Handwerker, “NEMI’s

Characterization of Lead-Free Alloy Applicable to

Today’s Commercially Available Alloys,” Circuits

Assembly, April 2004.

Schaefer, R.J., and D.J. Lewis, “Directional

solidification in a AgCuSn eutectic alloy,” Journal of

Electronic Materials, (in press), 2003.

Electrical Properties of On-Chip

Interconnections

Gayle, F., “FY2003 Programs and Accomplishments

– MSEL Materials for Micro- and Optoelectronics,

NISTIR 7019, 2004.

Josell, D., C. Burkhard, D. Kelley, Y.-W. Cheng,

R.R. Keller, T.P. Moffat, Y. Li, B.C. Baker, C.A. Witt,

and J.E. Bonevich, “Electrical properities of superfilled

Sub-100 nm silver metallizations,” Journal of Applied

Physics, 96 (1), 759–768, 2004.

Josell, D., S. Kim, D. Wheeler, T.P. Moffat, and

S.G. Pyo, “Quantifying superconformal filling of the

submicrometer features through surfactant catalyzed

chemical vapor deposition,” Proceedings of 2003 Spring

Meeting of Electrochemical Society in Paris, France,

PV 2003-8, pp. 98–103, 2003.

Josell, D., T.P. Moffat, and D. Wheeler, “An exact,

algebraic solution for the incubation period of superfill,”

Journal of the Electrochemical Society 151 (1),

C19–C24, 2004.

Moffat, T.P., and D. Josell, “Electrodeposition

of copper in the SPS-PEG-C1 additive system:

I. kinetic measurements: influence of SPS,” Journal of

Electrochemical Society 151 (4), C262–C271, 2004.

Turchi, P.E.A., R.M. Waterstrat, R. Kuentzler,

V. Drchal, and J. Kudrnovsky, “Electronic and phase

stability properties of V – X (X = Pd, Rh, Ru) alloys,”

Journal of the Physics of Condensed Matter, (in press),

2004.

Nanomagnetodynamics

Lewis, A.C., D. Josell, and T.P. Weihs, “Stability

in thin film multilayers and microlaminates: the role

of free energy, structure, and orientation at interfaces

and grain boundaries,” Scripta Materialia 48 (8),

1079–1085, 2003.

McMichael, R.D., “A classical model of extrinsic

ferromagnetic resonance linewidth in ultra-thin films,”

IEEE Transactions on Magnetics 40 (1), June 2004.

McMichael, R.D., “Ferromagnetic resonance

linewidth models for perpendicular media,” Journal

of Applied Physics 95 (1), 1 June 2003.

Magnetic Materials for Sensors and

Ultra-high Density Data Storage

Buchanan, J.D., T.P. Hase, B.K. Tanner,

C.J. Powell, and W.F. Egelhoff, Jr., “Interface

intermixing and in-plane grain size in aluminumtransition metal bilayers,” Physical Review B,

(submitted), 2004.

Chopra, H.D., Yang, D.X., Chen, P.J., and

W.F. Egelhoff, Jr., “Domain structure and

magnetoeleastic properttes of Fe/Pd ferromagnetic

thin films and multilayers,” Journal of Applied

Physics, (submitted), 2004.

Egelhoff, Jr., W.F., “Coercivities above 10 kOe

in CoPd superlattices,” Journal of Applied Physics,

(submitted), 2004.

Egelhoff, Jr., W.F., L. Gan, H. Ettedgui, Y. Kadmon,

C.J. Powell, P.J. Chen, A.J. Shapiro, R.D. McMichael,

J. Mallet, T.P. Moffat, M.D. Stiles, and E.B. Svedberg,

“Artifacts that mimic ballistic magnetoresistance,”

Journal of Magnetism and Magnetic Materials,

(submitted), 2004.

Egelhoff, Jr., W.F., L. Gan, H. Ettedgui, Y. Kadmon,

C.J. Powell, P.J. Chen, A.J. Shapiro, R.D. McMichael,

J. Mallet, M.D. Stiles, and E.B. Svedberg, “Artifacts in

ballistic magnetoresistance measurements,” Journal of

Applied Physics, 95, 7554, 2004.

Egelhoff, Jr., W.F., L. Gan, E.B. Svedberg,

C.J. Powell, A.J. Shapiro, R.D. McMichael, J. Mallet,

M.D. Stiles, and T.P. Moffat, “Artifacts that could

be misinterpreted as ballistic magnetoresistance,”

Digest of PMRC 2004, p. 248, 2004.

Hong, J.I., S. Sankar, A.E. Berkowitz, and

W.F. Egelhoff Jr., “Perpendicular anisotropy in Co/Pd

multilayers,” Journal of Magnetism and Magnetic

Materials, (submitted), 2004.

Huang, H., K. Seu, W.F. Egelhoff, Jr., and A. Reilly,

“Ultrafast pump-probe laser spectroscopy of the

half-metal CrO2,” Journal of Applied Physics,

(in press), 2004.

Lee, C.G., J.-G. Jung, V.S. Gornakov,

R.D. McMichael, A. Chen, and W.F. Egelhoff, Jr.,

“Effects of annealing on the GMR and domain structure

stabilization in a Py/Cu/Py/MnIr spin valve,” Journal

of Magnetism and Magnetic Materials 272, 1887,

2004.

Mallett, J.J., E.B. Svedberg, H. Ettedgui,

T.P. Moffat, and W.F. Egelhoff, Jr., “A search for

ballistic magnetoresistance (BMR) in electrodeposited

Ni nanocontacts: feedback control used to select

the contact resistance,” Applied Physical Letters,

(in press), 2004.
55

Metallurgy Division FY04 Annual Report Publication List

Mallet, J., E.B. Svedberg, S. Sayan, A.J. Shapiro,

P.J. Chen, W.F. Egelhoff, Jr., and T.P. Moffat,

“Compositional control in electrodeposited CoPt films,”

Electrochemical Solid State Letters, (in press), 2004.

Misra, R.D.K., S. Gubbala, A. Kale, and

W.F. Egelhoff, Jr., “A comparison of the magnetic

characteristics of nanocrystalline Ni, Zn, and Mn

ferrites synthesized by reverse micelle technique,”

Materials Science and Engineering, (in press), 2004.

Osofsky, M.S., R.J. Soulen, Jr., G. Woods,

and W.F. Egelhoff, Jr., “Enhanced Tc near the

metal/insulator transition: new insight into novel

superconducting materials,” Physical Review Letters,

(submitted), 2003.

Sanz, M., A. Papageorgopoulos, W.F. Egelhoff, Jr.,

M. Nieto–Vesperianas, and N. Garcia, “Wedge-shaped

absorbing samples look left handed: the problem of

interpreting negative refraction, and Its Solution,”

Physical Review E 67, Art. No. 067601, 2003.

Svedberg, E.B., J.J. Mallett, H. Ettedgui, L. Gan,

P.J. Chen, A.J. Shapiro, N. García, T.P. Moffat, and

W.F. Egelhoff, Jr., “Possible ballistic magnetoresistancelike artifacts in electrodeposited nanocontacts,” Journal

of Applied Physics, (in press), 2004.

Svedberg, E.B., J. Mallett, S. Sayan, A.J. Shapiro,

W.F. Egelhoff, Jr., and T.P. Moffat, “Recrystallization

texture and magnetic properties of electrodeposited

FePt on Cu (001),” (submitted), 2004.

Woods, G.T., R.J. Soulen, Jr., I.I. Mazin,

B. Nadgorny, M.S. Osofsky, J. Sanders, H. Srikanth,

W.F. Egelhoff, Jr., and R. Datla, “Analysis of pointcontact Andreev reflection spectra in spin polarization

measurements,” Physical Review B, (in press), 2004.

Yang, D.X., H.D. Chopra, P.J. Chen, and

W.F. Egelhoff, Jr., “Mixed-surfactants as a novel

approach to atomic engineering of spin values,”

IEEE Transactions of Magnetics, (submitted), 2004.

Yang, D.X., E.J. Repetski, H.D. Chopra, B.J. Spencer,

D.C. Parks, P.J. Chen, and W.F. Egelhoff, Jr., “A pinhole

coupling strength in giant magnetoresistance spin

valves: a statistical approach,” Physical Review B,

(in press), 2004.

Electrodeposited Pt1–x (Fe,Co,Ni)x Alloys

Mallet, J., E.B. Svedberg, S. Sayan, A.J. Shapiro,

W.F. Egelhoff, Jr., and T.P. Moffat, “Compositional

control in electrodeposition of FePt films,”

Electrochemical Solid State Letters, (submitted), 2004.

Zheng, L.A., E.V. Barrera, and R.D. Shull,

“Magnetic properties of the Co-C(d60) and Fe-C(d60)

nanocrystalline magnetic thin films,” Journal of

Applied Physics, (submitted), 2003.

Magnetic Properties and

Standard Reference Materials

Provenzano, V., J. Li, T.T. King, E.R. Canavan,

P. Shirron, M.J. DiPorrp, and R.D. Shull, “Enhanced

magnetocaloric effects in R3(Ga1–xFe x)5O12

(R = Gd, Dy, Ho; (O < x < 1) nanocomposites,”

Journal of Magnetism and Magnetic Materials

266, 185–193, 2003.

Provenzano, V., A.J. Shapiro, T.T. King,

E.R. Canavan, P. Shirron, M. DiPirro, and R.D. Shull,

“Peak magentocaloric effects in Al-Gd-Fe- alloys,”

Journal of Applied Physics, (submitted), 2004.

Provenzano, V., A.J. Shapiro, and R.D. Shull,

“Near-elimination of large hysteresis losses in the

Gd5Ge2S12 magnetic refrigerant compound by a

small alloying addition of iron,” Nature Journal,

(submitted), 2004.

Shir, F., L.H. Bennett, E. Della Torre, C. Mavripis,

L. Yanik, and R.D. Shull, “Details of the sequential

steps in magnetocaloric regeneration,” IEEE

Transactions on Magnetics, (submitted), 2004.

Shir, F., E. Della Torre, L.H. Bennett, C. Mavripis,

and R.D. Shull, “Modeling of magnetization and

demagnetization in magnetic regenerative refrigeration,”

IEEE Transactions on Magnetics, (submitted), 2004.

Shir, F., E. Della Torre, L.H. Bennett, C. Mavripis,

and R.D. Shull, “Modeling of magentization and

demagnetization in magnetic regenerative refrigeration,”

IEEE Transactions of Magnetics, (submitted), 2004.

Shull, R.D., E. Quandt, and A.J. Shapiro, “MOIF

observations of domain motion in magnetostrictive

materials under stress,” Journal of Applied Physics,

(submitted), 2004.

Taketomi, S., R.V. Drew, and R.D. Shull,

Anomalous magnetic aftereffect of a frozen magnetic

fluid,” Journal of Applied Physics, (submitted), 2004.

Taketomi, S., R.V. Drew, and R.D. Shull,

“Magnetic fluids’ phase transition between micelle

and mono-dispersed phases,” Physical Review E,

(submitted), 2004.

Taketomi, S., and R.D. Shull, “Experimental

verification of interactions between randomly

distributed fine magnetic particles,” Journal of

Magnetism and Magnetic Materials, (in press), 2003.
56

Metallurgy Division FY04 Annual Report Publication List

Turchinskaya, M.J., L.A. Bendersky, A.J. Shaprio,

K.S. Chang, I. Takeuchi, and A.L. Roytburd, “Rapid

constructing magnetic phase diagrams by magnetooptical imaging of composition spread films,” Journal

of Materials Research, (submitted), 2004.

Analysis of Structural Steel in the

World Trade Center

Gayle, F.W., S.W. Banovic, T. Foecke, R.F. Fields,

W.E. Luecke, J.D. McColskey, C. McCowan, and

T.A. Siewert, “The Structural Steel of the World Trade

Center Towers,” Advanced Materials and Processes,

(in press), October 2004.

Gayle, F.W., R.J. Fields, T.A. Siewert, and

W.E. Luecke, “Interim Report on Contemporaneous

Structural Steel Specifications,” June 2004 Progress

Report on the Federal Building and Fire Safety

Investigation of the World Trade Center Disaster, NIST

Special Publication 1000-5, pp. E–1 to E–61, 2004.

Banovic, S.W., “Interim Report on Inventory and

Identification of Steels Recovered from the WTC

Buildings,” June 2004 Progress Report on the Federal

Building and Fire Safety Investigation of the World

Trade Center Disaster, NIST Special Publication

1000-5, pp. F–1 to F–64, 2004.

Pipeline Safety

Datta, P.K., H.L. Du, J.S. Burnell–Gray, and

R.E. Ricker, “Corrosion of intermetallics,” ASM Metals

Handbook, Vol. 13, Corrosion, (in press), 2004.

Kolsky Bar (OLES Project)

Ma, L., J. Song, E. Whitenton, and T. Vorburger,

“A bullet signatgure measurement system for NIST RM

(Reference Material) 8240 standard bullets,” Journal of

Forensic Sciences 49 (4), 649–659, 2004.

Rhorer, R., D. Basak, G. Blessing, T. Burns,

M. Davies, B. Dutterer, R.J. Fields, M. Kennedy,

L.E. Levine, E. Whitenton, and H. Yoon, “Kolsky bar

with electrical pulse heating of the sample,” Proceedings

for Society of Experimental Mechanics Annual

Meeting, (submitted), 2003.

Rhorer, R.L., L.E. Levine, T.J. Burns, R.J. Fields,

H.W. Yoon, M.A. Davies, D. Basak, E.P. Whitenton,

G.V. Blessing, B.S. Dutterer, and M.D. Kennedy,

“Constitutive model data for machining simulation using

the NIST pulse-heated kolsky bar,” Dislocations,

Plasticity and Metal Forming, edited by A.S. Khan,

R. Kazmi, and J. Zhou, Fulton, MD: NEAT Press,

p. 103, 2003.

Yoon, H.W., D. Basak, R. Rhorer, E. Whitenton,

T. Burns, R.J. Fields, and L.E. Levine, “Thermal

imaging of metals in a kolsky-bar apparatus,”

Thermosense XXV, edited by E. Cramer and

X.P. Maldague, Proceedings of SPIE, 5073,

284–294, 2003.

Marine forensics

Hooper, J.J., T.J. Foecke, L. Graham, and

T.P. Weihs, “Metallurgical forensic analysis of wrought

iron from the RMS titanic,” Marine Technology,

SNAME N40(2), pp. 73–81, April 2002.

Kinetic Penetrators and Amorphous Metals

Biancaniello, F.S., T.F. Zahrah, R.D. Jiggetts,

L. Kecskes, L.J. Rowland, S.P. Mates, and

S.D. Ridder, “Structure and Properties of Consolidated

Amorphous Metal Powder,” Powder Materials:

Current Research and Industrial Practices III, edited

by F.D.S. Marquis, Warrendale, PA: TMS, 2003.

Other

Basak, D., R.A. Overfelt, and D. Wang,

“Measurement of specific heat capacity and electrical

resistivity of industrial alloys using pulse heating

techniques,” International Journal of Thermophysics,

24 (6), 1721–1733, 2003.

Benderksy, L.A., I.D. Fawcett, and M. Greenblatt,

“TEM study of two-dimensional incommensurate

modulation in layered La2–2x Ca1+2x Mn2O7

(0.6 < x < 0.8),” Chemical Materials, (submitted), 2004.

Bendersky, L.A., and I. Takeuchi, “Use of

transmission electron microscopy in combinatorial

studies of functional oxides,” Macromolecular Rapid

Comm., 25 (6), 695, 2004.

Bobordis, K., A. Seifter, A.W. Obst, and D. Basak,

“Radiance temperatures and normal spectral emittances

(in the wavelength range of 1500 nm to 5000 nm) of

tin, zinc, aluminum, and silver at their melting points by

a pulse-heating technique,” International Journal of

Thermophysics, (in press), 2003.

Bobordis, K., A. Seifter, A.W. Obst, and D. Basak,

“Validation of a new high-speed fiber-coupled

four-wavelength infrared pyrometer in the range of

505 k to 1234 k by a pulse-heating technique, using

the melting points of tin, zinc, aluminum, and silver

as reference points,” International Journal of

Thermophysics, (in press), 2003.
57

Metallurgy Division FY04 Annual Report Publication List

Boettinger, W.J., C.E. Campbell, T. Hansen,

P. Merewether, and B.A. Mueller, “Properties of

complex inorganic solids,” edited by P.E.A. Turchi,

A. Gonis, A. Meike, and K. Ragan, New York: Kluwer

Academics/Plenum Publishers, (in press), 2003.

Boettinger, W.J., D. Josell, S.R. Coriell, and

D. Basak, “Rapid melting of Nb – 47 mass % Ti:

effect of heating rate and grain size,” Solidification

Processes and Microstructures, edited by Rappaz,

Beckermann and Trivedi, Warrendale, PA: TMS,

pp. 87–98, 2004.

Chang, K.-S., M. Aronova, C.-L. Lin,

M. Murakami, M.H. Yu, J. Hattrick–Simpers,

O.O Famodu, S.Y. Lee, R. Ramesh, M. Wuttig,

I. Takeuchi, C. Gao, and L.A. Bendersky, “Exploration

of artificial multiferroic thin-film heterostructures using

compositon spreads,” Applied Physical Letters, 84

(16), 3091, 2004.

Famodu, O.O., J. Hattrick–Simpers, M. Aronova,

K.-S. Chang, M. Murakami, M. Wuttig, T. Okazaki,

Y. Furuya, L. Knauss, L.A. Bendersky, F.S. Biancaniello,

and I. Takeuchi, “Combinatorial investigation of

ferromagnetic shape-memory alloys in the Ni-Mn-Al

ternary system suing a composition spread technique,”

Materials Transactions, 45, 173, 2004.

Kramer, D.E., M.F. Savage, A. Lin, and

T.J. Foecke, “Novel method for TEM characterization

of deformation under nanoindents in nanolayered

materials,” Scripta Materialia, 50 (6), 745–749, 2004.

Lu, C.J., L.A. Bendersky, K. Chang, and

I. Takeuchi, “HRTEM study on the extended defect

structure of epitaxial Ba0.3Sr0.7TiO3 thin films grown

on (001) LaAl03,” Proceedings of MRS Symposium,

Vol. 751, 23.3, 2003.

Mates, S.P., F.S. Biancaniello, and S.D. Ridder,

“NIST experiments in gas atomization 1986–1999,”

Proceedings of the 2004 International Conference on

Powder Metallurgy and Particulate Materials, MPIF,

Princeton, NJ, (submitted), 2004.

Mates, S.P., F.S. Biancaniello, and S.D. Ridder,

“The effect of swirl on gas velocity decay in a generic

annular close-coupled nozzle,” Powder Materials:

Current Research and Industries Practices III, edited

by F.D.S. Marquis, Warrendale, PA: TMS, 2003.

Mates, S.P., and G.S. Settles, “A study of liquid

metal atomization using close-coupled nozzles, part 1:

gas dynamics,” Atomization and Sprays, (in press),

2003.

Mates, S.P., and G.S. Settles, “A study of liquid

metal atomization using close-coupled nozzles, part 2:

atomization behavior,” Atomization and Sprays,

(in press), 2003.

Ricker, R.E., “Modeling the influence of crack

path deviations on the propagation of stress corrosion

cracks,” Hydrogen Effects on Materials Behavior

and Corrosion Deformation Interactions, edited by

N.R. Moody, A.W. Thompson, R.E. Ricker, G.S. Was,

and R.H. Jones, Warrendale, PA: TMS, pp. 629–638,

2003.

Ricker, R.E., and A.K. Vasudevan, “The influence

of grain boundary precipitation on the stress corrosion

cracking of Al-Li and Al-Li-Cu alloys,” Hydrogen

Effects on Materials Behavior and Corrosion

Deformation Interactions, edited by N.R. Moody,

A.W. Thompson, R.E. Ricker, G.S. Was, and

R.H. Jones, Warrendale, PA: TMS, pp. 927–935, 2003.

Stoudt, M.R., and R.E. Ricker, “Electrochemical

evaluation of a corrosion fatigue failure mechanism in

a duplex stainless steel,” Metallurgical and Materials

Transactions A 35 (A) (8), 2427–2437, 2004.

Takeuchi, I., W. Yang, K.-S. Chang, M. Aronova,

T. Venkatasan, R.D. Vespute, and L.A. Bendersky,

“Monolithic multi-channel UV detector arrays and

continuous phase evolution in MgxZn1–xO composition

spreads,” Journal of Applied Physics 94, 7736, 2003.

Tsuda, T., C.L. Hussey, and G.R. Stafford,

Electrodeposition of Al-Mo Alloys from the lewis acidic

aluminum chloride-1 ethyl-3-methylimidazolium chloride

molten salt,” Journal of Electrochemical Society,

Vol. 151, Issue 8, pp. 379, 2004.

Tsuda, T., C.L. Hussey, G.R. Stafford, and

O. Kongstein, “Electrodeposition of Al-Zr alloys from

the lewis acidic aluminum chloride-1ethyl-3-

methylimidazolium chloride melt,” Journal of

Electrochemical Society, 151, C445, 2004.
58

Metallurgy Division FY04 Annual Report Publication List
59

Metallurgy Division

Metallurgy Division

Chief

Carol A. Handwerker

Phone: 301–975–6158

E-mail: carol.handwerker@nist.gov

Deputy Chief

Frank W. Gayle

Phone: 301–975–6161

E-mail: frank.gayle@nist.gov

NIST Fellows

William J. Boettinger

Phone: 301–975–6160

E-mail: william.boettinger@nist.gov

John W. Cahn

Phone: 301–975–5664

E-mail: john.cahn@nist.gov

Group Leaders

Electrochemical Processing Group

Gery R. Stafford

Phone: 301–975–6412

E-mail: gery.stafford@nist.gov

Magnetic Materials Group

Robert D. Shull

Phone: 301–975–6035

E-mail: robert.shull@nist.gov

Materials Performance Group

Stephen D. Ridder

Phone: 301–975–6175

E-mail: stephen.ridder@nist.gov

Materials Structure and Characterization Group

Frank W. Gayle

Phone: 301–975–6161

E-mail: frank.gayle@nist.gov

Metallurgical Processing Group

Stephen D. Ridder

Phone: 301–975–6175

E-mail: stephen.ridder@nist.gov
60

Research Staff

Research Staff

Drew, Rosetta V.

rossetta.drew@nist.gov

Magnetometry

Database maintenance

Egelhoff Jr., William F.

william.egelhoff@nist.gov

Magnetic thin films

Ultrasoft magnets

Magnetic sensors

Ultrahigh density data storage media

Fields, Richard J.

richard.fields@nist.gov

Mechanical properties

Mechanical testing

Powder consolidation

Metal forming

Fink, James L.

james.fink@nist.gov

Hardness standards

Hardness testing

Mechanical properties measurement

Metal powder consolidation

Environmental corrosion

Metallography

Foecke, Timothy J.

timothy.foecke@nist.gov

Metal forming standards

Nanostructured materials

Experimental fracture physics

SEM, TEM, SPM

Micro- and nano-mechanics of materials

Dislocation-based deformation mechanisms

Historical metallurgy and failure analysis

Gates, Hilary G.

hilary.gates@nist.gov

Standard reference materials

Gayle, Frank W.

frank.gayle@nist.gov

Structure/property relationships

Transmission electron microscopy

Intrastructural materials

Guyer, Jonathan E.

jonathan.guyer@nist.gov

III–V semiconductors

Molecular beam epitaxy

Alloy film deposition

Stress-induced mass transport

Banovic, Stephen W.

stephen.banovic@nost.gov

Metal forming

Mechanical properties

Texture analysis

Beauchamp, Carlos R.

carlos.beauchamp@nist.gov

Standard reference materials

Bendersky, Leonid A.

leonid.bendersky@nist.gov

Functional ceramics

Analytical and high-resolution TEM

Metal glasses

Combinatorial methods

Biancaniello, Frank S.

frank.biancaniello@nist.gov

Spray deposition measurements and diagnostics

Inert gas atomization: metal powder

measurements and consolidation

Nitrogenated steels, standard reference materials

Special alloys, bulk metallic glasses

Biomaterials

Boettinger, William J.

william.boettinger@nist.gov

Relation of alloy microstructures to processing

conditions; solidification

Thermal analysis

Solder

Bonevich, John E.

john.bonevich@nist.gov

Electron holography

Interfacial structure and chemistry

High resolution/analytical electron microscopy

Magnetic materials

Campbell, Carelyn E.

carelyn.campbell@nist.gov

Transient liquid phase bonding

Multicomponent diffusions simulations

Alloy design methodology

Claggett, Sandra W.

sandra.claggett@nist.gov

Specimen preparation for electron microscopy

Digital imaging

Specimen preparation for scanning electron

microscopy

Image analysis

Metallography of materials
61

Research Staff

Handwerker, Carol A.

carol.handwerker@nist.gov

Interface thermodynamics and kinetics

Solder science

Microstructure evolution

Iadicola, Mark

mark.iadicola@nist.gov

Mechanical properties

Mechanical testing

Stress measurement

Metal forming

Shape memory alloys

Jiggetts, Rodney D.

rodney.jiggetts@nist.gov

Substrate analysis

Grit blasting

Roughness measurements

Metallography of coatings

Image analysis

Micro analysis/characterization

Hot isostatic processing

Johnson, Christian E.

christian.johnson@nist.gov

Ultra-black coatings

Electroless deposition processes

Metallic glass alloy deposition

Microhardness SRM research

Chromium deposition

Pulse alloy deposition

Lead-free solder

Johnson, Frank

frank.johnson@nist.gov

Soft magnetic materials

Nanostructured metallic alloys

Magnetocaloric materials

Magnetic properties measurements

Metallographic analysis

Josell, Daniel

daniel.josell@nist.gov

Mechanical and structural properties

of multilayer materials

Electrical properties of submicrometer

interconnects

Filling of sub-100 nm features by

electrodeposition

Kattner, Ursula R.

ursula.kattner@nist.gov

Computational thermodynamics

Alloy phase equilibria evaluations

Solder alloy systems

Superalloy systems

Metal hydrogen systems

Kelley, David R.

david.kelley@nist.gov

Microhardness SRM development

Dye penetration SRM development

Precious metal electrodeposition

Plating on aluminum

Electroplating

Levine, Lyle E.

lyle.levine@nist.gov

Diffraction theory

Dislocation-based deformation

Synchrotron x-ray techniques

Percolation theory

TEM, SEM, SPM

Kolsky bar techniques

Nanomechanics

Multiscale modeling

Low II, Samuel R.

samuel.low@nist.gov

Hardness standards

Hardness testing

Mechanical properties of materials

Mechanical testing of material

Luecke, William E.

william.luecke@nist.gov

High-temperature mechanical testing

Fire-resistant steel

Creep of ceramics

Silicon nitride

Maranville, Brian B.

brian.maranville@nist.gov

Ferromagnetic resonance

Perpendicular magnetic media

Atomic force microscopy

Mates, Steven P.

steven.mates@nist.gov

Compressible fluid flow

Metal sprays

Fluid flow visualization

McMichael, Robert D.

robert.mcmichael@nist.gov

Giant magnetoresistance

Ferromagnetic resonance

Nanocomposites

Moffat, Thomas P

thomas.moffat@nist.gov

Electrochemistry

Scanning probe microscopy

Nanostructures

Surfactant mediated growth (ADD)
62

Research Staff

Shull, Robert D.

robert.shull@nist.gov

Nanocomposites

Magnetic susceptibility

Mossbauer effect

X-ray and neutron diffraction

Magneto-caloric and magneto-optical effects

Magnetic domain imaging

Stafford, Gery R.

gery.stafford@nist.gov

Electrochemical transients

Electrodeposition

Molten salt electrochemistry

Stress in thin films (ADD)

Stoudt, Mark R.

mark.stoudt@nist.gov

Deformation-induced surface roughness

Mechanical properties

Metal fatigue

Thin films

Environmentally assisted cracking

Warren, James A.

james.warren@nist.gov

Computer simulations of solidification

Dendrite pattern formation

Modeling of solder/substrate wetting processes

Modeling grain boundaries

Williams, Maureen E.

maureen.williams@nist.gov

Differential thermal analysis

Powder x-ray diffraction

Solder Wettability

SEM

Pierce Jr., Thomas A.

tpierce@nist.gov

Hardness measurements

Metallography

Pitchure, David J.

david.pitchure@nist.gov

Mechanical testing

Computer-aided design

Mechanical engineering

Rantschler, James O.

rantschl@nist.gov

Ferromagnetic resonance

Magnetic characterization

Damping formalisms

Ricker, Richard E.

richard.ricker@nist.gov

Corrosion mechanisms

Deformation mechanisms

Stress corrosion cracking (SCC)

Hydrogen embrittlement

Corrosion fatigue

Dynamic mechanical analysis

Ridder, Stephen D.

stephen.ridder@nist.gov

Metal powder production and characterization

Metal spray processing

Process metallurgy, modeling, and control

Shapiro, Alexander J.

alexander.shapiro@nist.gov

Magnetic domain imaging

Mossbauer effect

Scanning electron microscopy (SEM) and

X-ray microanalysis

Image analysis
63

Organizational Charts

Organizational Charts

Materials Science and Engineering Laboratory

Polymers

E.J. Amis, Chief

C.R. Snyder, Deputy

Metallurgy

C.A. Handwerker, Chief

F.W. Gayle, Deputy

Ceramics

D.L. Kaiser, Chief

R.G. Munro, Deputy

Materials Reliability

A.F. Clark, Chief

T.A. Siewert, Deputy

NIST Center for

Neutron Research

P.D. Gallagher, Director

Director

Deputy Director

National Institute of Standards and Technology

Director

Boulder Laboratories

Baldrige National Quality

Program

Director for

Administration

& Chief Financial

Officer

Technology

Services

Advanced

Technology

Program

Manufacturing

Extension

Partnership

Manufacturing

Engineering

Laboratory

Chemical Science

and Technology

Laboratory

Materials Science

and Engineering

Laboratory

Electronics and

Electrical Engineering

Laboratory

Information

Technology

Laboratory

Physics

Laboratory

Building and

Fire Research

Laboratory

L.E. Smith, Director

S.W. Freiman, Deputy Director
64