bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrodeposition of Metallic Nanowires in Nanoporous Polycarbonate Films
Authors: Ohgai Takeshi , Mizumoto Masayuki , Nomura Shigeki , Kagawa Akio
Published: March 2009

A polycarbonate membrane filter with numerous cylindrical nanopores was used as a
template for growing metallic nanowires such as Ni, Co and Fe. The nanoporous template with
pore-diameter of 150 nm, pore-length of 6000 nm, and pore-density of 108 pore•cm-2 was modified as
a cathode with sputter-deposited gold layer. Inside the nano-pores, the metallic nanowires were
electrochemically deposited from an acidic sulfate solution containing metal ions. The growth rate of
metallic nanowires depended on the cathode potential during electrodeposition. The diameter of
electrodeposited nanowires corresponded to that of nanopores in the template. TEM diffraction
pattern suggested that each metallic nanowire composed of a single crystalline structure.
Short Stack Performance of Intermediate Temperature - Operating Solid Oxide Fuel Cells with Hydrocarbon Fuel Processor
Authors: Bae J. , Jee H. , Kim J. , Yoo Yung Sung
Published: March 2009

For intermediate temperature operation, we chose an anode-supported, planar type SOFC
(Solid Oxide Fuel Cell) design considering mass production with use ferritic stainless steels as
cost-effective interconnects. Anode-supported single cells with thin electrolyte layer of
YSZ(Yttria-Stabilized Zirconia) were fabricated and short stacks were built and evaluated. We also
developed diesel and methane autothermal reforming(ATR) reactors in order to provide fuels to
SOFC stacks. Influences of the H2O/C(steam to carbon ratio), O2/C(oxygen to carbon ratio) and
GHSV(Gas Hourly Space Velocity) on performances of stacks have been investigated. Performance
of the stack operated with a diesel reformer was lower than with using hydrogen as a fuel due to lower
Nernst voltage and carbon formation at anode side. The stack operated with a natural gas reformer
showed similar performances as with using hydrogen. Effects of various reformer parameters such as
H2O/C and O2/C were carefully investigated. We found O2/C is a sensitive parameter to control stack
performance.
Microstructure and Creep of γ-TiAl Containing β-Stabilizer
Authors: Seo Dongyi , Saari H. , Au Peter , Beddoes J.
Published: March 2009

Fully lamellar structures of powder metallurgy (PM), investment cast, and directionally
solidified (DS) TiAl alloys containing β stabilizer were produced after stepped cool heat treatment,
and interface β precipitates were formed after aging at 950°C. In addition, a columnar grain
structure combined with a fully lamellar structure aligned with the load direction and interface β
precipitates were formed by directional solidification and subsequent heat treatments. Creep test
results of PM TiAl indicate that controlling the initial microstructures is also critical for balancing
the primary and steady-state creep resistance during short and long-term tests. DS TiAl alloy
exhibits a significant reduction of the primary strain and creep rate compared to polycrystalline TiAl
due to the unique DS microstructure. Therefore, a DS microstructure with proper lamellar
orientation and controlled interface β precipitation is the ideal if maximum time to a relatively small
(<0.5%) strain is the design criterion of merit.
Tensile Properties and Creep Behavior of Compositional Modified Orthorhombic Ti2AlNb Alloys
Authors: Mao Yong , Hagiwara Masuo
Published: March 2009

Several beta stabilizing elements such as Mo, Cr, W, V and Fe have been added to Ti-
22Al-27Nb alloy for substituting a portion of Nb in order to further improve the tensile properties
and creep resistances of orthorhombic Ti2AlNb-based alloys. Six compositional modified alloys Ti-
22Al-19.2Nb-2Cr, Ti-22Al-12.5Nb-2W-2Cr, Ti-22Al-10.8Nb-2Mo-2Cr, Ti-22Al-16Nb-2Cr-2V,
Ti-22Al-11Nb-2Mo-1Fe, Ti-22Al-16.3Nb-2V-1Fe were prepared by plasma arc melting. The phase
constitutions of these alloys were found to be B2+O or B2+O+α2 phases. The tensile properties
were investigated at room temperature, and the creep behaviors were investigated under
650oC/310MPa and 650 to 750oC/200MPa. The results showed that Mo+Fe and W+Cr addition
improved effectively the 0.2% yield strength and creep resistance. Ti-22Al-11Nb-2Mo-1Fe alloy
exhibited the lower transient creep strain and steady-state creep rate, and longer 1% creep-strain
lifetime than Ti-22Al-27Nb alloy at 650 to 700oC creep. The dislocation-controlled creep
deformation mechanism was suggested to the creep behaviors of the Mo+Fe-modified alloy.
Intergranular and Pitting Corrosion Behavior of Fe-25Al-6Cr Intermetallic Compounds Containing Mo, Nb and B
Authors: Choe Han Cheol , Park S.J. , Eun S.W. , Ko Yeong Mu
Published: March 2009

In order to investigate the intergranular and pitting corrosion behavior of Fe-25Al-6Cr
intermetallic compounds containing Mo, Nb and B, 11 kinds of Fe-25Al were prepared by arc
melting in Ar gas, using high purity aluminum and iron. The fabricated materials were heat treated
for homogenious structure and stabilization of the iron aluminides. The electrochemical methods
were used for interganular and pitting corrosion. Effects of Mo, Cr, Nb and B on the repassivation
current density(Ir) and the active current density(Ia) of Fe-25Al-6Cr were recorded in the following
order: Mo<Cr<Nb<B, with boron showing the highest active current density(Ia). Mo addition also
proved to be most efficient in reducing the thickness of the intergranular corrosion. The pitting
potential was increased in the order of Mo>Cr>Nb>B, from the highest to the lowest respectively.
Laparoscopic Surgical Manipulations Affect the Mechanical Properties and the Microstructure of Polymeric Sutures
Authors: Tremblay Sonia , El Maliki A. , Fiset Michel , Mantovani Diego
Published: March 2009

In the last years a new clinical method to carry out surgical operations has been introduced.
It consists in minimally invasive vascular surgery (also called laparoscopy). In one hand, during
laparoscopy procedures, sutures cannot be handled with fingers, and the use of stainless-steel needle
holders is required. In the other hand, companies that fabricate sutures clearly mention that
metal-made devices should be avoided when manipulating the monofilaments. Therefore, the
manipulation of the suture monofilaments (made of polymers) by laparoscopic needle holders (made
of metals) is controversial. Literature in this field is limited and incomplete. Therefore, the aim of this
study was to investigate the mechanical and microstructural effects of the manipulations with
laparoscopic needle holder on polymeric suture monofilament. Surgipro© (polypropylene),
Teflene© (polyvinylidene fluoride) and Gore-Tex© (polytetrafluoroethylene) monofilament suture
were pinched with a standard clinical protocol by a surgeon. Scanning electron microscopy,
micro-mechanical testing, differential scanning calorimetry, x-ray diffraction, small angle x-ray
scattering and Fourier transform infrared spectroscopy were then performed. Results showed that the
ultimate tensile strength of Teflene and Gore-Tex sutures does not change after pinching whereas it
decreases significantly for Surgipro sutures. This is attributed to stress concentration and to the
compressive strength applied on the monofilament, which are closely related to the permanent
deformation of the suture after pinching. Teflene and Gore-Tex monofilament sutures showed to be
not affected even after severe pinching with laparoscopic needle holders. Therefore, our results
clearly showed that the use of Surgipro II sutures in laparoscopic interventions should be avoided.
Mechanical Joining of Magnesium Components by Means of Inductive Heating - Realization and Capability
Authors: Hahn Ortwin , Horstmann Magnus
Published: March 2009

The aspect of lightweight constructions becomes more and more important. This
particularly applies to the automotive industry which wants to lower the fuel consumption by a
smaller vehicle weight. Under this point of view in recent years steel has often been replaced by
aluminum alloys. In comparison with this the application of lightweight magnesium alloys, whose
specific density is appropriate within the range of plastics, opens further prospects for weight
reduction. The pre-condition for this purpose is the supply of suitable joining processes for
magnesium alloys, which are universally applicable and offer the maximum utilization of the
materials of the joined parts under operating loads. Mechanical joining techniques provide the
opportunity of connecting magnesium components homogeneously as well as in material mix.
However, the anisotropic deformation characteristics of the hexagonal crystal structure of magnesium
at room temperature contain the application for mechanical joining techniques. Only starting from
temperatures of approx. 225°C a sufficient plastic deformation and thus a crack-free shaping of the
magnesium material is given. Therefore preheating of magnesium substrates leads to a broad
extension of deformability and offers the chance to realize a high quality mechanical joint. This article
describes a process-safe realization of the mechanical joining operations clinching, self piercing
riveting and clinch riveting of magnesium sheets by means of an inductive heating of the substrates in
laboratory scale. In this context, feasibilities and limits of the considered joining techniques are
shown.
Superior Corrosion Resistance and Mechanical Properties of a Mg Alloy Recycled by Solid-State Process
Authors: Chino Yasumasa , Mabuchi Mamoru
Published: March 2009

Superior mechanical properties of the recycled specimen by solid-state recycling were
introduced at first. AZ31 Mg machined chips were recycled by extrusion at 673 K with the different
extrusion ratios. The oxide contaminants were dispersed more uniformly in the recycled specimen
with the high extrusion ratio (1600:1). There was a remarkable increase in tensile strength and 0.2%
yield stress for the recycled specimen with the high extrusion ratio compared with an extrusion
reference subjected to the same deformation history. Next, superior corrosion resistance of the
recycled specimen was introduced. The recycled specimen with low extrusion ratio (45:1) possessed
superior corrosion resistance compared with the extrusion reference. The enhancement of corrosion
resistance for the recycled specimens was attributed to the presence of oxide contaminants which
were distributed parallel to the extrusion direction.
New Composite Metal Foams under Compressive Cyclic Loadings
Authors: Rabiei Afsaneh , Neville Brian , Reese Nick , Vendra Lakshmi
Published: March 2009

New composite metal foams are processed using powder metallurgy (PM) and gravity
casting techniques. The foam is comprised of steel hollow spheres, with the interstitial spaces
occupied by a solid metal matrix (Al or steel alloys). The cyclic compression loading of the
products of both techniques has shown that the composite metal foams have high cyclic stability
at very high maximum stress levels up to 68 MPa. Under cyclic loading, unlike other metal
foams, the composite metal foams do not experience rapid strain accumulation within collapse
bands and instead, a uniform distribution of deformation happen through the entire sample until
the densification strain is reached. This is a result of more uniform cell structure in composite
metal foams compared to other metal foams. As a result, the features controlling the fatigue life
of the composite metal foams have been considered as sphere wall thickness and diameter,
sphere and matrix materials, and processing techniques as well as bonding strength between the
spheres and matrix.
Femtosecond Laser Ablation of Zr55Al10Ni5Cu30 Bulk Metallic Glass
Authors: Sano Tomokazu , Takahashi Kengo , Hirose Akio , Kobayashi Kojiro F.
Published: March 2009

Dependence of the femtosecond laser ablation depth on the laser pulse energy was
investigated for Zr55Al10Ni5Cu30 bulk metallic glass. Investigation of the femtosecond laser ablation
of bulk metallic glasses has not been reported. Femtosecond laser pulses (wavelength of 800 nm,
pulse width of 100 fs, pulse energies of 2 – 900 μJ) were focused and irradiated on the polished
surface of metals in air. The ablation depth of the metallic glass is deeper than that of its crystallized
metal at a pulse energy in the strong ablation region. We suggest that the energy loss at grain
boundaries of hot electrons which is accelerated by the laser electric field influence the ablation
depth in the strong ablation region.
Analysis of Optimal Compositions of Ternary Bulk Metallic Glasses with Thermodynamic Quantities
Authors: Takeuchi Akira , Inoue Akihisa
Published: March 2009

The relationships of optimal compositions of bulk metallic glasses (BMGs) have been
analyzed with a set of thermodynamic quantities of mismatch entropy normalized with respect to
Boltzmann's constant (Sσ!/kB) and mixing enthalpy (Hmix) and with assistance of classification result
of BMGs. The analysis shows clear dependence of the location of Sσ!/kB and Hmix values for optimal
compositions of ternary BMGs in Sσ!/kB-Hmix chart in each alloy system. The ternary BMGs are
summarized into four types: (1) Cu-based, (2) La-, Zr- and Ca-based, (3) Pd-based and (4) Fe- and
Mg-based BMGs according to their maximum value of Sσ!/kB ((Sσ!/kB)max) and the largest and negative
value of Hmix ((Hmix)L.N.) or their half values which are obtained for each system. These types of
BMGs are related with the local arrangements of BMGs, which are widely accepted as an icosahedral
structure for Metal-Metal type, a transformed tetragonal dodecahedrons and triacontrahedrons
structure for Pd-Metalloid type, and a network-like structure for Metal-Metalloid type.
Anomalous SWAXS Analysis of Zr-Cu-Ni-Al Quaternary Metallic Glass Joints
Authors: Okuda Hiroshi , Murase Isao , Ochiai Shojiro , Yokoyama Yoshihiko , Inoue Katsuaki
Published: March 2009

Anomalous small and wide angle scattering measurements on electron-beam welded
joint has been carried out at Zr absorption edge. We preformed an anomalous and simultaneous
small- and wide-angle scattering (A-SWAXS) analysis on the welded joint with and without
crystallization. For the wide angle measurements, we extend the SAXS measurements up to 13
nm-1, where q is still below the first halo, but is large enough for several Bragg peaks to be
observed. In the present analysis, the ASAXS analysis at the HAS/beads interface is
interpreted in conjunction with the corresponding AWAXS analysis. The origin of SAXS and
WAXS was found to be different.
Change of Nanostructure in (Fe0.5Co0.5)72B20Si4Nb4 Metallic Glass on Annealing
Authors: Hirata Akihiko , Hirotsu Yoshihiko , Amiya Kenji , Nishiyama Nobuyuki , Inoue Akihisa
Published: March 2009

Nanoscale structural change in (Fe0.5Co0.5)72B20Si4Nb4 bulk glassy alloy on annealing
has been investigated using transmission electron microscopy. On annealing at temperatures
above 773K, electron diffraction intensity analysis showed a clear structure change for a
Cr23C6-type local atomic ordering. The local structure formation of Cr23C6-type nanophase was
confirmed by nanobeam electron diffraction. A development process of dense precipitates of the
Cr23C6-type nanophase was further studied by high-resolution electron microscopy. It was found
that the formation of the highly-dense nanoprecipitates provides an increase in Vickers hardness.
Intergranular Fatigue Cracking Enhanced by Impurity Segregation
Authors: Daniel Claire , Christien Frédéric , Le Gall René
Published: March 2009

It was previously reported that fatigue life of some alloys can be dramatically reduced if the
grain boundaries contain a high level of impurity segregation before fatigue tests. In this paper the
susceptibility of single phase brass samples (90Cu10Zn) to this form of damage is studied. After cold
drawing of as cast brass bars, fatigue samples were heat treated at 800°C during 30min to promote
recrystallization and impurity segregation at grain boundary. The samples were then tested under high
frequency bending fatigue test at 200°C. After cracking, fracture surfaces were studied using both
scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The SEM
micrographs showed that the fractures were mostly intergranular. Chemical composition of
intergranular cracks surface were analyzed using EPMA at low accelerating voltage. A high
concentration of sulfur was found on most of grain boundary facets. The internal stress in alloys after
fatigue was qualitatively estimated using electron backscattering diffraction in scanning electron
microscopy. A high level of local misorientation was found near most grain boundaries. The
mechanism of intergranular cracks formation during fatigue is discussed taking into account both the
segregation of sulfur at grain boundaries and accumulation of plastic strain at grain boundaries
Investigations on Structure and High Temperature Properties of Iridium
Authors: Merker Jürgen , Fischer Bernd , Lupton David F. , Witte Joerg
Published: March 2009

Due to its outstanding mechanical properties at high temperatures and chemical stability
iridium is used for demanding high temperature applications. In order to obtain materials data
necessary for the design of high temperature equipment and the numerical simulation of their
service performance the stress-rupture strength and creep behaviour have been investigated in a
temperature range between 1650°C and 2300°C. The results of metallographic and fracture
examinations (SEM) revealed that, in common with other pure metals, unalloyed iridium shows
marked grain growth at high temperatures. Under these conditions, the deformation characteristics
of iridium may not be entirely uniform and predictable, as will be demonstrated with examples from
the creep studies. Both metallographic examination and investigations by means of scanning
electron microscopy gave indications of possible causes for a significant anomaly in the creep
behaviour. It is therefore advantageous for the mechanical properties if a fine-grained microstructure
can be maintained even at the highest service temperatures.
Improvement of Materials Efficiency for a Sustainable Resource Management
Authors: Simon Franz Georg
Published: March 2009

Industry has to handle two major cost factors: labor and materials. To improve
competitiveness, companies usually try to optimize the personnel cost which leads, however, to
augmentation of unemployment. In spite of this, materials costs are often higher than the cost for labor
in producing industries. Beside this economic aspect lower materials consumption is also a benefit for
the environment.
In Germany, a program was started in 2004 by the German government to improve materials
efficiency. A study has been undertaken to identify potential fields of improvement in the industry and
potential measures to achieve improvements in materials efficiency. According to the results of the
study improvement of materials efficiency can be achieved by application of interdisciplinary
technologies, reduction of waste and cuttings (“zero-loss management”), improved product quality
and optimization of construction and product design (“design to cost”). Another tool within the
program is the competition for the German Materials Efficiency Award dedicated to small and
medium-sized enterprises, given to best-practice examples of materials efficiency in small and
medium-sized enterprises.
The paper discusses the different categories of efficiency and the environmental impact of
materials consumption considering the concept of TMR (Total Materials Requirement). With the
concept of TMR (Total Materials Requirement) it is possible to express the total mass of primary
materials extracted from nature including “hidden” flows to generate raw material for industrial
production.
Modelling of Precipitation Hardening in Alloys: Effective Analytical Submodels for Impingement and Coarsening
Authors: Starink Marco J.
Published: March 2009

To predict strength evolution of precipitation hardening alloys, a wide range of modelling
approaches have been proposed. The most accurate published models are physics-based approaches
which use both nanoscale processes with their related constants and parameters, as well as parameters
calibrated to one or more macroscale measurements of yield strength of one or more samples. Recent
developments in submodels including analytical expressions for volume fraction and size evolution
including impingement and coarsening are reviewed. It is also shown that Kampmann-Wagner and
JMAK models are generally not consistent with data on the progress of precipitations in the main
precipitation hardening Al alloys systems, and improved model formulations are described.
3-D High-Density Strain Mapping Procedure Based on High-Resolution CT
Authors: Kobayashi Masakazu , Toda Hiroyuki , Ohgaki Tomomi , Uesugi Kentaro , Wilkinson David S. , Kobayashi Toshiro , Kawai Yuji , Aoki Yoshimitsu
Published: March 2009

A tracking procedure for the high-resolution X-ray computed tomography (CT) has been
developed in order to measure 3-D local strain within a deforming material in high-density. A
dispersion-strengthened copper alloy model sample with alumina particles, which contains micropores,
was visualized by the synchrotron radiation CT. The pores observed in reconstructed CT
volumes were used as tracking markers. The developed tracking method using a set of matching
parameters, which classifies matched, pended and rejected markers, exhibited high ratio of success
tracking. Furthermore, the ratio was improved by applying the spring model method, which is one
of the particle image velocity (PIV) methods utilized in the field of the fluid mechanics, to the
pended markers. The method based on the image analysis of CT imaging volumes provides us 3-D
high-density strain mapping.
Thermal Applications of Cellular Lattice Structures
Authors: Wadley Haydn N.G. , Queheillalt Douglas T.
Published: March 2009

Numerous methods have recently emerged for fabricating cellular lattice structures with
unit cells that can be repeated to create 3D space filling systems with very high interconnected pore
fractions. These lattice structures possess exceptional mechanical strength resulting in highly
efficient load supporting systems when configured as the cores of sandwich panels. These same
structures also provide interesting possibilities for cross flow heat exchange. In this scenario, heat is
transported from a locally heated facesheet through the lattice structure by conduction and is
dissipated by a cross flow that propagates through the low flow resistant pore passages. The
combination of efficient thermal conduction along the lattice trusses and low flow resistance through
the pore channels results in highly efficient cross flow heat exchange. Recent research is investigating
the use of hollow truss structures that enable their simultaneous use as heat pipes which significantly
increases the efficiency of heat transport through the lattice and their mechanical strength. The
relationships between heat transfer, frictional flow losses and topology of the lattice structure are
discussed and opportunities for future developments identified.
Analytical and Computational Models for Investigations of Local Buckling in Honeycomb Sandwiches
Authors: Pahr D.H. , Rammerstorfer F.G.
Published: March 2009

This work highlights and solves problems with the prediction of the compressive strength, limited by
local instabilities, of sandwich material compounds based on honeycomb cores and very thin
facesheets. Analytical methods in conjunction with periodic finite element unit cell models are
utilized for this task. The finite element models are found to be well suited for all kinds of buckling
predictions. Different uni- and bi-axial loadings are considered as well as influences of core height,
core material, core geometry, and facesheet thickness are investigated. Finally, a new analytical
approach is introduced for the treatment of the rather unexpected core cell wall buckling under
in-plane compression of the sandwich, which predicts the critical load very accurately.
Using of FEM to Analyse of the Reinforcement Bar Rolling Process
Authors: Szota Piotr , Dyja Henryk
Published: March 2009

Reinforcement bars are chiefly used in the building industry at production of reinforced concrete
constructions and as working elements in bridge building. An important factor for strength joining
bar and concrete are dimensions and positioning of ribs at the bar’s surface.
In this paper the computer simulation of the rolling of the round reinforcement bar is presented. It
has been performed in order to define the specific features of the mode of metal flow in the roll gap
and to determine the effect of the shape and dimensions of the roll on the pitch of the ribs of the
finished bar.
Structural Models of Progressive Interface Failure under Shear Stresses
Authors: Monetto Ilaria
Published: March 2009

This paper deals with the problem of decohesion in composite structures containing
interfaces of similar/dissimilar materials. The analysis of the tractions transmitted between opposite
faces into contact as well as of the initiation and propagation of delamination zones is studied with
reference to plane structures with adhesive joints under shear stresses. A simplified monodimensional
structural model is formulated and applied to develop basic understanding of the
standard adhesion test. The analytical results obtained are used to optimize the performance of
single-lap adhesive joints in practical applications.
Investigation of Sintering of Spherical Copper Powder by Micro Focus Computed Tomography (μCT) and Synchrotron Tomography
Authors: Nöthe Michael , Schulze Matthias , Grupp Rainer , Kieback Bernd , Haibel A.
Published: March 2009

The two-particle model describes the approach of particle centres and the growth of the
interparticle contacts during sintering of metal powders. Unfortunately the comprehensive description
of processes inside of three dimensional specimens must consider the contribution of particle
rearrangements. The recent developments of combined micro focus computed tomography (CT) and
3D photogrammetric image analyzing give the opportunity to obtain the experimental data required to
overcome the shortcomings of sintering theories based on the two-particle model. The analysis of
spherical poly and single crystalline copper powder was performed by CT. In addition a single
crystal specimen was analyzed by high resolution synchrotron radiation tomography - a more
sophisticated analysis method with very limited availability. The analysis of the 3D tomographic
image by photogrammetric image analyzing yielded the positions and radii of all particles and their
contact partners as well. A statistical analysis of the retrieved data was performed. The formation and
breaking of necks during sintering could be observed. An in-depth analysis of the particle rotation
with respect to the coordination number and local density will be presented.
Nanotubes Obtained from Mono and Bimetallic Carbides Produced by Mechanical Alloying
Authors: Díaz-Barriga Arceo Lucia , Rendón-Vázquez L. , Orozco Eligio , Garibay-Febles V. , Palacios Gonzalez E. , Leyte Guerrero F.
Published: March 2009

The main purpose of this work was to produce nanotubes using a two step method:
mechanical alloying and heat treatment. Mechanical Alloying (MA) was used to prepare the
monometallic Co3C carnide and the bimetallic C-25%at Ni-25%at Mo carbide with Ti impuririties
by milling of pure elemental powders of cobalt, molibdenum, titanium and carbon, in a high-energy
rotatory mill under an Ar atmosphere. The nanocrystalline carbides were used to produce metal
filled nanotubes and nanoparticles, by means of precipitation after heating for 15 minutes at 800°C.
Microstructural characterisation of the as-milled and heat-treated powders was performed using
Transmisssion Electron Microscopy (TEM) techniques. It was possible to obtain filled nanotubes,
carbide nanorods, and observe a nucleation phenomena inside carbon cavities.
Optimization of Nb HSLA Microstructure Using Advanced Thermomechanical Processing in a CSP Plant
Authors: DeArdo Anthony J. , Marraccini R. , Hua Ming Jian , Garcia C. Isaac
Published: March 2009

There are two obstacles to be overcome in the CSP production of HSLA heavy gauge strip and
skelp, especially for API Pipe applications. First, the microalloying should be conserved by eliminating the
high temperature precipitation of complex particles. Second, the heterogeneous microstructure that
normally results from the 800 micron initial austenite in the 50mm slab as it is rolled to 12.5mm skelp must
be eliminated to optimize the final microstructure and improve the final mechanical properties. Alteration in
the hot rolling sequence can strongly homogenize the final austenite and resulting final ferritic
microstructure. When coupled with a low coiling temperature near 550°C, the new rolling practice can
result in Nb HSLA steels that can easily meet requirements for strength, toughness and ultrasonic testing in
12.5mm skelp gauges for X70 API pipe applications. The underlying physical metallurgy of these two
breakthroughs will be presented and discussed in detail.
Grain Refinement in High-Purity α-Iron Base Alloys during Thermomechanical Processing
Authors: Lim S.M. , Desrayaud Christophe , Girard S. , Montheillet Frank
Published: March 2009

Thermomechanical processing involving severe plastic deformation (SPD) is a popular
approach to ultrafine grain formation in bulk samples. In the present study, two grades of highpurity
α-iron were deformed within the ferritic domain in cold and warm torsion to large strains (>>
1). Examination of the deformed samples using orientation imaging microscopy revealed a highly
fragmented, lamellar structure aligned almost parallel to the direction of shear. Between 37 and
54 % of boundaries detected are high angle ones (HAB). Some of these HAB are associated with
the original grain boundaries. However, a good number are believed to originate from dislocation
accumulation processes, during which the misorientation angle across certain strain-induced low
angle boundaries (LAB) rises with increasing strain. The resultant microstructure is composed of
ultrafine crystallites on the order of 1 – 2 1m. In fact, localised regions of equiaxed grains on the
micron scale were observed within samples deformed between room temperature and 300 °C.
Nonetheless, other areas remain relatively unfragmented despite persistent straining until failure. At
higher temperatures, the microstructure is more homogeneous, but the average grain size is
coarsened. Optimal grain refinement thus appears to be a compromise between several competing
factors: large strains at relatively low temperatures for high dislocation density, higher temperatures
to enable sufficient dynamic recovery, and low grain boundary mobility that is aided by low
temperatures and/or pinning by solute atoms or second phase particles. Furthermore, the
development of a torsion texture composed of a single ideal orientation at large strains is
unfavourable towards the generation of HAB.
Study of Ultrafine Grain Structure of a Pipeline Steel
Authors: Chen Wayne , Ferguson David , Li Gui Yan , Ao Lie Ge , Wang Chun Ming , Zhang Jian , Ma Hui Xia
Published: March 2009

A series of severe strain compression tests of a pipe line steel were conducted using the
MAXStrain® system. The tests were run at different thermal mechanical conditions including
controlled cooling rates. 1-2 micron ultrafine grain microstructure was achieved. The
characteristics of the ultrafine grain structure and precipitates were examined using optical
microscope, SEM, and TEM, and the relationship between the processing conditions and
microstructure and precipitates were studied.
Effect of Ausageing on the Precipitation Behavior of MX Carbonitride in Modified 9Cr-1Mo Steel
Authors: Yoshino Masataka , Mishima Yoshinao , Toda Yoshiaki , Kushima Hideaki , Sawada Kota , Kimura Kazuhiro
Published: March 2009

The precipitation behavior of MX carbonitride during a normalizing heat treatment with and
without ausageing was investigated in a modified 9Cr-1Mo steel. The normalizing heat treatment was
performed at 1150 oC for 1800 s. Ausageing was conducted at 765 and 500 oC for 1800 to 86400 s during the
cooling from the heat treatment. The matrix of the steel was austenite single phase during normalizing and
ausageing, except for that ausaged at 765 oC for 86400 s. The initial austenite grain size and hardness were
not influenced by ausageing, except for the sample ausaged at 765 oC for 86400 s. Although Nb-rich MX
(NbX) and cementite were observed, V-rich MX (VX) was not observed under any of the conditions
investigated. The amount of NbX in the steel ausaged at 500 oC was at least twice as large as that under the
other conditions, and the amount in the steel ausaged at 760 oC was slightly larger than that in the steel that
did not undergo ausageing. The precipitation of NbX took place during ausageing in the austenite matrix. On
the other hand, it is well known that VX precipitates during tempering. An equilibrium mole fraction of VX
in the austenite matrix calculated by Thermo-Calc. was larger than that of NbX at the ausageing temperatures.
It is proposed that VX is an equilibrium phase at the ausageing temperature; however, VX nucleation takes
much longer in the austenite matrix. It is postulated that the precipitation of VX is more strongly influenced
by the interfacial energy rather than supersaturation. It is concluded that the precipitation of MX carbonitride,
especially NbX, can be controlled by ausageing during cooling after a normalizing heat treatment.
Contribution of Z-Phase Precipitation to Recovery of Martensitic Structure in High Chromium Creep Resistant Steel
Authors: Sawada Kota , Kushima Hideaki , Kimura Kazuhiro
Published: March 2009

The precipitation site, main metallic composition and number density of Z phase have
been investigated in T91 in order to clarify the influence of Z phase formation on recovery of
martensitic structure and creep strength degradation. The Z phase particles were mainly present
around prior austenite grain boundaries and/or packet boundaries in the steels crept at 550oC and
600oC. The Z phase particles were found in specimens crept at 550oC to 650oC. There was no
indication of Z phase formation up to about 62475.0 h at 500oC and 14106.5 h at 700oC. The Nb
content of Z phase observed at 550oC was lower than that at 600oC. The number density of Z phase
measured at 550oC was lower that that at 600oC, indicating that the preferential recovery of
martensitic lath structure around prior austenite grain boundary is not remarkable at 550oC in
contrast with 600oC.
Two-Phase Microstructures of Gamma+Gamma-Prime Formed by Phase-Separations due to Heat-Treatments of Elastically Constrained Ni-Al-Ti Alloys
Authors: Doi Minoru , Kozakai Takao , Moritani Tomokazu , Naito Shizuo
Published: March 2009

In the elastically constrained Ni-Al-Ti alloy system, three kinds of phase-separations, i.e.
microstructure changes, take place to bring the two-phase state of γ+γ’ depending on the alloy
compositions and heat treatments: 1) in Ni-8at%Al-6at%Ti, the phase-separation of γ phase takes
place and γ’ particles appear in the γ matrix, 2) in Ni-13at%Al-9at%Ti, the phase-separation of γ’
intermetallic phase takes place and γ particles appear in the γ’ matrix, 3) in Ni-8.5at%Al-5.4at%Ti,
the phase-separation of γ’ precipitate phase takes place and γ particles appear in the γ’ precipitate.
The Validation of Microstructural Prediction in Nickel Superalloys
Authors: Brooks Jeffery W. , Tin S. , Guest R.P.
Published: March 2009

Forged parts, specifically designed for the validation of microstructural models, have been
manufactured in Inconel alloy 718 using a wide range of thermo-mechanical histories. The
microstructural evolution observed in the forged samples has been compared with predictions from
two models for dynamic recrystallisation and grain growth.
Development of New Alloys with Excellent High Temperature Creep Characteristics of 700°C or More
Authors: Muneki Seiichi , Okubo Hiroshi , Okada Hirokazu , Igarashi Masaaki , Abe Fujio
Published: March 2009

The carbon and nitrogen free new alloys which were composed of the supersaturated
martensitic microstructure with high dislocation density before the creep test have been investigated
systematically. These alloys were produced from the new approach which raised creep strength
by the utilization of the reverse transformed austenite phase as a matrix and intermetallic
compounds such as Laves and μ-phases as precipitates during creep test. It is important that
these alloys are independent of any carbides and carbo-nitrides as strengthening factors. Creep
behavior of the alloys is found to be different from that of the conventional high-Cr ferritic heat
resistant steels. The minimum creep rates of the Fe-Ni alloys at 700°C are found to be much
lower than that of the conventional steel, which is due to fine dispersion strengthening useful even
at 700°C in these alloys. As a result carbon and nitrogen free alloys exhibited superior creep
properties at temperatures more over 700°C, and steam oxidation resistance.
Tailoring the Mechanical Properties of Al-Sn-Alloys for Tribological Applications
Authors: Schouwenaars Rafael , Torres J.A. , Jacobo Víctor H. , Ortiz Armando
Published: March 2009

A 95% cold-rolled Al-20%Sn-1%Cu alloy was heat-treated in a range of temperatures
and times to investigate the evolution of mechanical properties and microstructure. The most
interesting combination of properties can be achieved between 300 and 400°C in a process that is
simpler than what is used in industry. The physical phenomena which are active during the heat
treatment are precipitation, recovery, recrystallisation and change in phase distribution due to
surface tension. The former two predominate at low temperatures, while the latter achieve faster
kinetics at higher temperatures, where recrystallisation is coupled to the change in morphology of
the contiguous Sn-phase.
Intelligent Materials Synthesis Based on Millimeter-Wave Heating and SPS Methods
Authors: Makino Yukio , Yoshioka T. , Saito H. , Sano Saburo , Akedo Jun , Miyake Shoji
Published: March 2009

Characteristics of heating processing based on millimeter-wave or pulsed high current
are discussed from the standpoint of the interaction between electromagnetic energy and solid
materials. Capabilities of the electromagnetic processing are indicated by exemplifying several
successful results such as millimeter-wave sintering of AlN, millimeter-wave post-annealing of
aerosol-deposited PZT films and synthesis of single-phase nano-structured anatase by SPS (or
pulsed high current heating). It is shown in these examples that well-characterized properties such
as high thermal conductivity and preferential orientation are created by the inherent effect due to the
electromagnetic field, which is called microwave or SPS effect in millimeter-wave or SPS
processing.
Effect of Magnetic Field on Martensitic Transformation Temperature in Ni2MnGa with Single Variant and Multi-Variant States
Authors: Fukuda Takashi , Kim Jae Hoon , Kakeshita Tomoyuki
Published: March 2009

We have studied effect of magnetic field on the martensite (10M) to intermediate phase
transformation temperature (As) of Ni2MnGa in order to understand the influence of
magnetocrystalline anisotropy on the transformation temperature under a magnetic field. In case of
the transformation from multi-variant 10M phase to the intermediate phase, As decreases with
increasing magnetic field H for H < 0.8 MA/m, and then it increases on further increasing H. On the
other hand, in case of the transformation from the single-variant 10M to the intermediate phase, As
increases monotonically with increasing H, where the easy axis of the single variant is parallel to
the field direction. The difference between the multi-variant and single variant state can be
explained by considering the high magnetocrystalline anisotropy of the martensite phase.
Preparation of Fe2VAl Thermoelectric Module by RF Sputtering
Authors: Matsumoto Akihiro , Masashi Mikami , Kobayashi Keizo , Ozaki Kimihiro , Nishio Toshiyuki
Published: March 2009

An attempt to prepare Fe2VAl deposited film and the thermoelectric module using RF
sputtering has been made. Sputtering target has been prepared using mechanical alloying of
metallic powders and the subsequent pulse current sintering process. The obtained deposited film
has had a lack of aluminum content compared to the composition of the starting material.
Controlling of aluminum content for the preparation of Fe2VAl sputtering target has made it
possible to obtain the desired material composition. The film has had the experimental
thermoelectric force being similar to the one estimated from the measured thermoelectric data of the
materials. Fe2VAl thermoelectric module of eight pairs with a film thickness of 4 μm has had an
electric force of 31mV and 5.6μW.
The Effects of Geometrical Factors on the Step-Up Ratio in Piezoelectric Transformer
Authors: Yoon Man Soon , Yoon T.S. , Kim J.R. , Choi Y.G. , Ur Soon Chul
Published: March 2009

The electromechanical properties of a newly proposed 3-dimensional piezoelectric transformer have been investigated. Especially, the effects of 3-dimensional geometry on the maximum tip displacement were carefully investigated. As a result, it was found that the maximum strain of the 3-dimensional piezoelectric device was significantly enhanced up to 4.5 times higher than that of a disk shape device. This data were in good agreement with the finite element model analysis of strains and vibration modes. Moreover, a very high voltage step-up ratio of 290 (10 times higher than the Rosen type), sustaining efficiency more than 96%, were achieved.
Stored Energy and Recrystallization Process
Authors: Baczmanski Andrzej , Wierzbanowski Krzysztof , Benmarouane Abdelilah , Lodini Alain , Lipiński Paul , Bacroix Brigitte
Published: March 2009

Stored energy plays a crucial role in recrystallization process. One can distinguish two
contributions to this energy. The first one is the elastic energy, connected with residual
stresses, i.e., with grain-grain interaction. Another part of the stored energy is due to
dislocation density, which is mainly localized inside grains. The latter one is considered as a
main driving force of recrystallization. However, the stored energy connected with residual
stresses can also have some influence on this process. Both types of energy can be determined
experimentally and predicted by deformation models. Taking into account both types of the
stored energy, some features of recrystallization textures can be explained.
Modeling Compression and Tension Reloads in Copper Prestrained by Rolling
Authors: Beyerlein Irene J. , Tomé Carlos N.
Published: March 2009

A constitutive model is applied to predict the flow stress of an fcc material up
to 30% straining after rolling to reductions of 19%, 39%, and 50%. The model makes
use of a single crystal hardening law which appreciates the directional anisotropy
produced by planar dislocation boundaries, Bauschinger effects, and dissolution of
substructure by new slip activity invoked by changes in strain path. Anisotropy between
axial testing in the rolling (RD) versus the transverse direction (TD) and a tensioncompression
stress- differential in RD are predicted. These and other characteristics of
the flow curves are linked to changes in slip activity when deformation transitions from
rolling to axial testing.
Grain Boundary Engineering: Progress and Challenges
Authors: Wang Wei Guo
Published: March 2009

The progress of grain boundary engineering (GBE) is overviewed and the challenges for
further investigations emphasized. It points out that, the electron backscatter diffraction (EBSD)
reconstruction of grain boundaries, which gives the information of connectivity interruption of
general high angle boundaries (HABs), is more significant than purely pursuing high frequency of
so-called special boundaries. The criterion for the optimization of grain boundary character
distribution (GBCD) needs to be established. The energy spectrum and the degradation
susceptibility of grain boundaries of various characters including HABs and low Σ（Σ≤29）
coincidence site lattice (CSL) needs to be studied and ascertained. And finally, the newly proposed
model of non-coherent Σ3 interactions for GBCD optimization are discussed.
Experimental and Numerical Investigation of Texture Development during Hot Rolling of Magnesium Alloy AZ31
Authors: Schmidt C. , Kawalla Rudolf , Walde Tom , Riedel Hermann , Prakash A. , Poizat Christophe
Published: March 2009

Due to the deformation mechanisms and the typical basal texture rolled magnesium
sheets show a significant asymmetry of flow stress in tension and compression. In order to avoid
this undesired behavior it is necessary to achieve non-basal texture during rolling, or at least, to reduce
the intensity of the basal texture component. The reduction of the anisotropy caused by the
basal texture is very important for subsequent forming processes. This project aims at optimizing
the hot rolling process with special consideration of texture effects. The development of the model
is carried out in close cooperation with the experimental work on magnesium alloy AZ31 .The experimental
results are required for the determination of model parameters and for the verification of
the model. Deformation-induced texture is described by the visco-plastic self-consistent (VPSC)
model of Lebensohn and Tomé. The combination of deformation and recrystallization texture models
is applied to hot compression tests on AZ31, and it is found, that the model describes the observed
texture and hardening/softening behavior well. In some cases rotation recrystallization occurs
in AZ31 which appears to be a possibility to reduce the undesired basal rolling texture.
Texture Development in Polycrystalline Fe-Ga Magnetostrictive Materials
Authors: Cheng Leon M. , Summers Eric
Published: March 2009

Magnetostrictive Galfenol (Fe-Ga) is a promising and mechanically robust actuator
material. Single crystals of Galfenol have been shown to exhibit up to 400 ppm magnetostrictive
strains with saturating fields of several hundred oersteds. However, due to the high conductivity of
Galfenol, it needs to be in thin sheet form for many device applications to avoid eddy current loses.
One of the main challenges in producing engineering components from these materials is shaping
of these materials while retaining a preferred crystallographic texture to optimize the
magnetostrictive performance of the polycrystals. In this work, the effects of rolling on texture
evolution of polycrystalline Galfenol are being investigated. Results from hot rolling experiments
showed that careful control of rolling conditions can minimize the formation of cracks. They also
suggested that significant dynamic recovery and recrystallization occurred during the deformation
process, resulting in a large number of grain orientations with very little texture. Preliminary
results also showed that the specimens can be successfully warm rolled to a thickness of less than
0.5 mm.
Effect of Film Thickness and Annealing Temperature in Stress-Induced Damage in Metal Films
Authors: Joo Young Chang , Hwang Soo Jung
Published: March 2009

Hillocks were observed in various thick Al films after annealing for a long time and their
density and diameter were measured using an image analysis program. The hillock density decreased
while the diameter increased with increasing film thickness. The total hillock volume per unit area of
the film is linearly proportional to the film thickness and annealing temperature. Based on the results
of our investigation, the effect of the film thickness, grain size and annealing temperature on hillock
formation is discussed, and an equation that can be used to predict the hillock density and average
hillock diameter is suggested.