bluuebunny/crossref_metadata_2025 huggingface dataset:
Tensile Strength of Perfect Cubic Crystals under Superimposed Transverse Plain Stress
Authors: Černý Miroslav , Pokluda Jaroslav
Published: March 2009

Influence of biaxial stress applied perpendicularly to the [100] loading axis on the tensile
stress-strain response is studied from first principles. Crystals of four cubic metals Mo, W, Ir and
Au were selected as particular case studies. The results obtained show that, within a limited range of
biaxial stresses, the tensile stress increases almost linearly with increasing transverse biaxial stress.
The factor that expresses the slope of the linear function changes with applied tensile strain.
A region of tensile stability of cubic crystals is also discussed.
Properties of Permeable Concrete Substrate Having Dual Pore Structures
Authors: Yang Z. X. , Hwang Kyu Hong , Yoon Jeong Bae , Kim J.O. , Kim M.C.
Published: March 2009

Porous concretes with continuous voids have been gaining more interest as an ecological material because of their useful functions such as water permeability and adsorption ability. Especially, to make porous concrete much more environmentalized, micropores play a role of nest for microorganism and germs to live in. So micropore distribution and the size of micropores especially open pores are the key point . In this study, the size and distribution of micropores of porous concrete were effected by the AE agents to the cement pastes and then by the treating types, treating times, treating temperatures, and the vacuum pressure during the treating. And another group specimens were added sodium bicarbonate and alum. And then physical properties were examined, digital microscope was also used to observe the micropores sizes and distributions. Cracks were observed on the cement-aggregate joint when the amount and vacuum pressure increased. And high treating temperature shows no good on the bonding of cement paste and aggregate.
Performance of Photocatalysis/Chemical Oxidants in Aqueous TiO2 Suspensions
Authors: Jung Jong Tae , Kim Jong Oh , Choi Jae Young
Published: March 2009

This study was conducted to evaluate the effect of a photocatalysis/oxidant system for the
treatment of humic acid and heavy metals in aqueous solutions. Hydrogen peroxide, ozone and
potassium peroxodisulfate were tested as oxidants. The effect of the oxidant concentration was
conducted with a pH of 7, a UV intensity of 64 W and a TiO2 dosage of 0.3 g/L. The addition of
oxidants over the amounts of H2O2 50 mg/L, O3 20 g/m3 and K2S2O8 50 mg/L inhibits the system
efficiency. The negative effect of the high concentration of oxidants likely results from OH radical
quenching caused by the excess oxidant. Therefore, the optimal dosages for the oxidants such as a
hydrogen peroxide, ozone and potassium peroxodisulfate were found to be 50 mg/L, 20 g/m3 and 50
mg/L, respectively. The addition of an oxidant in the UV/TiO2 system enhanced the degradation
efficiency of humic acid and heavy metals compared to no addition of an oxidant. The degradation
efficiency of humic acid and heavy metals was much greater for the UV/TiO2/H2O2 system.
Development of Free Nitric acid, Non-P Desmut Solution for Surface Treatment Aluminium Alloys
Authors: Son Seong Ho , Kwon Dae Chol , Jeong Do Won
Published: March 2009

The purpose of this study is to develop non nitric acid desmut to cope with environment
regulation and at the same time, to obtain the effect comparable to nitric acid in removing smut. For
this, some desmut solutions were produced adding 2~3 chemical reagents to basic components such
as peroxide, ammonium group, ferric group compounds and acid. And, electrochemical treatment was
tried to remove ammoniacal nitrogen(NH3-N) in desmut solution after desmut treatment.
Consequently, we could gain smut-removing ratio of 90% using the solution mixed with peroxide,
ammonium group, ferric group compounds and sulfuric acid at 35°C for 70 seconds, and the ratio is
almost the same with that using nitric acid type desmut solution. In this work, most nitrogen(T-N) was
confirmed to be ammoniacal nitrogen(NH3-N). In addition, we succeeded in controlling
ammonia-nitrogen below 60 ppm corresponding to environment regulation by electrochemical
treatment in the wastewater.
Refractive Index of SiO2-B2O3-Al2O3 Glasses
Authors: Won Ju Yeon , Lee Sang Wook , Kim Dong Sun , Lee Jung Ki , Hwang Seong Jin , Kim Hyung Sun
Published: March 2009

Photolithographic process is one of the eco-friendly processes for forming the pattern of the barrier ribs in PDP. Controlling the refractive index of glass is important to develop a photosensitive paste for photolithographic process. We studied the refractive index and the structural transition of these glasses by measuring the refractive index, reflectance, density and dielectric constant with changing the SiO2/B2O3 ratio in the SiO2-B2O3-Al2O3 glass system. The refractive index was investigated to the relationship between the thermal and optical properties depending on the composition. It suggests that the thermal and optical properties in borosilicate glasses should be correlated to the glass structure with the SiO2/B2O3 ratio.
Mechanical Performances of ZTM/SiC Nanocomposite Optimized through Composition and Microstructure Tailoring
Authors: Jin Xi Hai , Gao Lian , Sun Jing
Published: March 2009

SiC/ZTM nanocomposites were prepared, and the influence of nanosized SiC addition on the microstructure and mechanical properties were investigated. It was found that the addition of nanosized SiC significantly retarded the matrix grain growth, making the microstructure much finer and more uniform. This led to a significant improvement in the mechanical properties. And further enhancement in the mechanical property can be achieved through the addition of mullite seeds in the starting powder and improving the distribution homogeneity of SiC nanoparticles in the matrix.
Effect of Mechanical Milling on the Microstructure and Hydrogen Interaction of Both Mm-Ni and MmNi5-Ni Mixtures
Authors: Esquivel Marcelo R. , Meyer Gabriel
Published: March 2009

Mechanical milling (MM) and a combination of MM and temperature heating were
used to synthesize the intermetallic MmNi5 and a MmNi5-Ni mixture, respectively. The
process evolution with time was analyzed by scanning electron microscopy (SEM) and X-ray
diffraction (XRD). SEM was used to characterize size and morphology of particles in order to
reveal the governing mechanisms during the milling of each system. X-ray diffraction (XRD)
was utilized to determine strain and crystallite size changes introduced by milling. The effects
of integrated milling time on the sorption properties of the MmNi5-Ni mixture were analyzed.
Results were correlated to defects introduced into microstructure. A comparison of the final
characteristics of alloys obtained in each case is also shown.
Single-Line Diffraction Profile Analysis Method Used for Evaluation of Microstructural Parameters in the Plain Ferritic Steel upon Tensile Straining
Authors: Davydov Vadim , Lukáš Petr , Strunz Pavel , Kužel Radomír
Published: March 2009

The modification of the Transformed Model Fitting /TMF/ [1] method developed for
evaluation of the single-line profiles from high-resolution neutron powder diffractometers is
proposed [2]. More sophisticated real-space model [3] is used for the distortion and crystallite size
broadening of the diffraction lines. The new PC program based on this model has been tested on
neutron diffraction profiles collected in situ upon tensile deformation tests of the plain ferritic steel.
The deformation test was performed in the incremental mode in which each individual deformation
step was followed by unloading. The neutron diffraction spectra were collected both upon loading
and unloading and behavior of the diffraction profiles in elastic as well as in plastic region of the
deformation curve was examined in detail. Comparison of microstress values in loaded/unloaded
state and in elastic and plastic region offers interesting possibility to separate the contribution of the
type II and type III microstresses.
Imaging Diffraction Using Maxim at G3/Hasylab - Spatial Resolved Strain Measurements on Linear Friction Welded Dissimilar Materials (AA7020-T6/Ti6AlV
Authors: Rothkirch André , Lenser Sabine
Published: March 2009

Strain induced by friction welding of dissimilar materials was determined by an imaging
diffraction technique using the Material X-ray diffraction Imaging (MAXIM) detector at
HASYLAB G3. Applying the sin2Ψ method in ω mode, a stress profile perpendicular to the weld
joint was derived. Results are discussed and compared with measurements of the same specimen
made at the neutron source of the GKSS Research Centre.
Experimental/Modelling Study of Residual Stress in Al/SiCp Bent Bars by Synchrotron XRD and Slitting Eigenstrain Methods
Authors: Song Xu , Chardonnet Solène , Savini Giancarlo , Zhang Shu Yan , Vorster Willem J.J. , Korsunsky Alexander M.
Published: March 2009

The aim of the study presented here was to evaluate the residual stresses present in a bar
of aluminium alloy 2124-T1 matrix composite (MMC) reinforced with 25vol% particulate silicon
carbide (SiCp) using X-ray diffraction and 3D profilometry (curvature measurement using
Mitutoyo/Renishaw coordinate measurement machine) and comparing these results with numerical
models of residual strain and stress profiles obtained by a simple inelastic bending model and Finite
Element Analysis (FEA). The residual strain distribution was introduced into the test piece by
plastic deformation in the 4-point bending configuration. At the first stage of this study the elasticplastic
behaviour of the MMC was characterized under static and cyclic loading to obtain the
material parameters, hardening proprieties and cyclic hysteresis loops. Subsequently, synchrotron Xray
diffraction and CMM curvature measurements were performed to deduce the residual stress
profile in the central section of the bar. The experimental data obtained from these measurements
were used in the inelastic bending and FEA simulations. The specimens were then subjected to
incremental slitting using EDM (electric discharge machining) with continuous back and front face
strain gauge monitoring. The X-ray diffraction and incremental slitting results were then analysed
using direct and inverse eigenstrain methods. Residual stresses plots obtained by different methods
show good agreement with each other.
In Situ Monitoring of Weld Transformations to Control Weld Residual Stresses
Authors: Stone Howard J. , Bhadeshia Harshad K.D.H. , Withers Philip J.
Published: March 2009

The level of residual stresses generated in fusion welds has been a major area of interest
for many years. For steels, a major influence on the final state of stress is through martensitic
transformation. This is because the martensitic transformation is accompanied by significant shear
and volume strains. One way to mitigate the development of residual stress is by controlling the
onset of the transformation such that the associated strain is able to compensate for thermal
contraction all the way down to ambient temperatures. In the past it has only been possible to follow
the evolution of the phase transformation during cooling of the weld metal using indirect methods
such as dilatometry and differential scanning calorimetry. This paper describes the first work in
which the phases present are characterized directly during the cooling of reheated weld metal at
conditions typical of those encountered during welding by installing a thermomechanical simulator
on a synchrotron diffraction beam line at ESRF.
In Situ Analysis of Deformation Mechanisms of Cu-Based fcc Materials under Uniaxial Loading
Authors: Klosek Vincent , Mathon Marie Helene , Aouni M.H. , Chiron Rémi , Ji Vincent
Published: March 2009

By associating texture determinations and strains measurements by neutron diffraction,
the elastoplastic behaviours of families of crystallites with the same crystallographic orientations
were characterized in situ in a brass and a bronze alloys under uniaxial loading. The polycrystalline
orientation analysis method proposed here allows an intermediate approach between a “local”
(intragranular) and a “global” characterization, within the bulk of massive samples.
The Influence of Temperature on Cr-Ti Coating in Carbon Steel
Authors: Lou Bai Yang , Luo Kang Chun , Xu Bin
Published: March 2009

It is considered that Ti-Cr coatings can improve strength, hardness, wear resistance
and corrosion resistance of base control alloys as these coatings combine the advantages of both Ti
coating and Cr coating. In this study, the Ti-Cr coatings were deposited by diffusion method. The
effects of deposition temperatures on the compositions and microstructures of the Ti-Cr coatings on
45# carbon steel were investigated. The coatings formed consisted of three layers. The outer layer
contained Ti and Cr carbides beneath which a diffusion layer was developed. The inner layer was
enriched in Ti and Cr. At low temperature (800°C) the outer layer of Ti-Cr coatings was dominated
by TiC. Increasing deposition temperature led to the enhanced diffusion of Cr and a Cr7C3 and
Cr23C6-dominated outer layer was identified. The growth process of Ti-Cr coating was analyzed and
simulated.
Weight Calculation of Steel Pipe by Visual Basic Programme
Authors: Zhang Yan Wen , Wang Ji Hui , Ji Yun Dong
Published: March 2009

Weight calculation of steel pipe by hand is difficult and apt to be inaccurate .It could be
solved easily by Visual Basic programme.The programme is simple and intuitionistic. The
efficiency and exactness have been improved greatly.
Impact of Rolling Conditions on Propagation of a Potential Crack
Authors: Fabík Richard , Kliber Jiří , Aksenov Sergey
Published: March 2009

The paper reveals information about crack behavior during hot rolling of heavy-gauge
products. FEM-based mathematical modeling has been used to investigate the impact of crack shape
and rolling parameters on the distribution of the principal tensile stress and the Cockroft-Latham
fracture criterion value and on the crack closing capacity. The results clearly show that the crack
shape has the most powerful influence on the observed quantities followed by the rolling geometry
factors. To find a critical value of the LCK for a specific steel grade and an actual rolling process, a
laboratory experiment has been conducted, in which problems related to propagation of initial
cracks were detected. It consisted in rolling of wedge-shaped specimens with a notch, which was
introduced for the purpose of raising the probability of crack occurrence. In order to find the
Critical LCK value in the area of the notch, an additional computer simulation was performed.
Results of these experiments led to the conclusion that the steel possesses excellent formability. The
Critical LCK values were up to 300 MPa, which is, essentially, an order higher than in actual
rolling. As the critical value of LCK depends, among others, on the metallurgical characteristics of
the metal, the key to the issue is in the steel microstructure. The findings brought the conclusion
that in this specific case the rolling itself affects the crack propagation to a small extent only. The
heating process poses a much greater challenge, as it is the likely stage involving the steel
overheating.
The Finite Element Analysis of Serrated Chip Formation in High-Speed Cutting Auto Panel Dies
Authors: Ruan Jing Kui , Ke Ying Lin , Yang Yong
Published: March 2009

On the base of analyzing material constitutive model, chip-tool contact friction, and chip
separation and fracture, a finite element model (FEM) was built to study the high-speed machining
process of alloy cast-iron. The shaping process of serrated chip in high-speed milling alloy cast-iron
was simulated and analyzed in detail. It was shown that machining parameters affect the serrated
chip forming greatly. The model can be used to optimize machining parameters, prolong tool life
and improve machining surface quality.
A New Optimization Method of Constitutive Equation for Hot Working Based on Physical Simulation and Numerical Simulation
Authors: Li Fu Guo , Wang Xiao Na , Yu Xiao Lu
Published: March 2009

This paper advances a new optimization method about material constitutive equation on
the basis of physical simulation and numerical simulation results which basic thinking can be
described as the following: through comparing the results of the material deformation process under
actual experimental conditions and virtually simulated by the finite element numerical simulation
method with the constitutive equation established on the basis of the physical simulation, the
constitutive equation established by the experimental data is optimized in turn. Based on it, this paper
advances a visco/plastic constitutive equation to depict the semi-solid thixo-forming and the
constitutive equation is analyzed and optimized through coupling of the physical simulation and
numerical simulation. It is observed that this method can effectively eliminate the influence of the
factor outside material itself on the constitutive equation. So, it can exactly depict the deformation
behavior of the materials and improve the accuracy and reliability of the numerical simulation.
Deforming Mechanisms of Two-Pass Drawing Process of an Aluminum Tube from Circular to Rectangle Section
Authors: Quan Guo Zheng , Wang Meng Han , Zhou Jie , Tong Ying
Published: March 2009

The aluminum tube with rectangle section can be produced by two-pass drawing process
including non-plug and with-plug drawing. It is an effective method to study the deforming
mechanisms by simulation, based on which the section varying of two-pass drawing got schemed and
the relevant dies with reasonable dimensions got designed. The dynamics model and elasto-plastic FE
model of the non-plug and with-plug drawing were established based on FEM software, then the
simulation was performed. The sizing section of drawing die got optimized with angle β=178°, which
eliminated instability. The influence of different semi-die angle 2 a on drawing load was researched,
and a proper value of 2 a and 1 a was found. The touch boundary and touch-stress distribution of
transitional drawing were achieved. Furthermore the residual stress and spring-back strain
distribution after final drawing were achieved, which contributes to modifying the dimensions of
rectangle sizing section.
Investigation on M-A Constituent in Weld CGHAZ of High-Strength Microalloyed Steel
Authors: Chen Cui Xin , Li Wu Shen , Peng Hui Fen
Published: March 2009

Thermal simulating technology was used to simulate weld CGHAZ of microalloyed
steel with different thermal cycle for the purpose of investigation on morphology of M-A
constituent and its influence on toughness. The experimental results showed that in comparison
with base metal specimens after thermal cycle have poorer toughness for its larger size, elongated
and sharp massive shape and non-uniform distribution. Toughness of specimen value has
maximum value with maximum area fraction for cooling time of 7s, and then it will drop whether
cooling time is longer or shorter. Moreover, its mean chords of all specimens are all smaller than
0.5μm. Only those with the length larger than 2μm or the length-width ratio exceeding 4, cleavage
fracture can occur. So it is concluded that M-A constituent is not the main influencing factor of
impairing toughness for steel with different thermal cycle for its smaller mean chord and area
fraction.
Numerical Analysis on Temperature Field of Axial Alternating Magnetic Field-Assisted Electric Field-Activated Sintering
Authors: Guo L. , Li Yuan Yuan , Li Xiao Qiang , Yang Jun Yi
Published: March 2009

The numerical simulation and experimental measurement of temperature distribution
in electrical field activated sintering of titanium powders were carried out. The simulated and
experimental results were in good agreement. It was shown that the sintering temperature
gradually decreased from the center of sample to the outer. To improve the performance of
sintered material, the sintering temperature gradient had to minimize. A method, electric
field-activated sintering coupled with axial alternating magnetic field, was proposed to
homogenize sintering temperature field. The simulation of sintering temperature field was also
conducted under different magnetic field intensity. It was proved that the maximum radial
sintering temperature difference in sample was reduced by about three fourths, owing to the skin
effect of induced current caused by alternating magnetic field.
New Technology for NDT Weld Inspections – Phased Arrays and Diffraction Sizing
Authors: Labbé Simon , Moles Michael
Published: March 2009

This article describes new techniques and technology for inspecting welds using
automated ultrasonics. The prime new technology is phased arrays, while the new techniques
are Time-of-Flight Diffraction and S-scan back diffraction. The relationship of phased arrays
with North American codes is briefly given, along with an inspection result, comparing
radiography, pulse-echo phased arrays and TOFD.
Tail Breaking Force in Thermosonic Wire Bonding with Novel Bonding Wires
Authors: Lee J. , Mayer Michael , Zhou Y. , Hong S.J. , Lee S.M.
Published: March 2009

Tail breaking forces (TBFs) are measured for various process conditions to understand
phenomena such as short tail formation. TBFs obtained with several Cu wires are compared to find
the most suitable Cu wire type that improves consistent tail formation. In situ online TBF
measurement method is developed. The highest TBF obtained is 61.59 + 9.10mN. The highest Cpk
value obtained is 2.97 + 0.33 when lower specification limit of 10 mN is assumed.
Engineered Weld Design: Are Composite Welds Likely in the Future?
Authors: Olson D.L. , Park Young Do , Liu S. , Jackson J.E. , Lasseigne-Jackson A.N. , Metzbower E.
Published: March 2009

Utilizing alternating welding process parameters, deposition practices, and welding
consumables, particularly during multiple pass welding, it is possible to improve a variety of weld
metal properties. There are available a number of phenomena occurring during welding that allow
weld metal designers the ability to generate macro- and micro-structural features amenable to
implementation of composite theory. These phenomena include solidification microsegregation
during dendrite growth, gas-metal reactions between the selected alternating shielding gas
composition and weld pool, and solidification microstructural orientation during welding.
Additional methods of producing composite welds including specially designed weld compositions,
weld metal solidification modification by arc pulsing, and dual wire deposition may be utilized to
achieve single pass and multipass composite weld metal deposition. Composite welds are a
potential method to solve challenging demands such as high-toughness at low temperature, creep
strength at high temperature, and customized design for corrosion, wear, or cracking resistance.
Advanced Resistance Spot Welding Technologies: New Machine, Adaptive Control and FEM Simulation
Authors: Cho Yong Joon , Chang In Sung , Lee Heui Bom
Published: March 2009

While resistance spot welding (RSW) has been the most successful sheet metal joining
process in automotive industry, there are still certain quality and reliability issues due to the control
system and its application process. Some weld spots have hard-to-reach areas and new materials
make the process more complicated resulting in new challenges for quality welds. Recently, a new
welding machine called one-sided RSW was introduced to make a weld of hard-to-reach areas in
automotive application. Intelligent current regulation algorithm of welding machine timer helps to
control welding current and time with more stablility than conventional constant current regulation.
Newly developed RSW simulation tool is another advanced technology to improve weld quality and
production stability. In this research, advanced RSW technologies, including one-sided RSW,
intelligent adaptive control, and simulation of RSW process, are discussed with various automotive
applications.
Monitoring of Backside Image of Molten Pool during Aluminum Pipe Welding Using Vision Sensor
Authors: Baskoro Ario Sunar , Kabutomori Masashi , Suga Yasuo
Published: March 2009

This paper proposes an image sensing system for the TIG (Tungsten Inert Gas) welding
process of aluminum pipe. In automatic welding process, it is important to recognize the molten
pool during the welding process. The use of CCD camera as vision sensor obtains the information
of molten pool. The research was conducted for welding of aluminum alloy Al6063S-T5 with
controlled welding speed and the AC welding polarity. Firstly, histogram analysis and range of
brightness threshold was established. Secondly, by using the differential value of brightness of
molten pool, the edge of molten pool can be detected. Finally, to overcome the unsteady detected
edge, the ellipse approximation was used to obtain the image parameters, which are width, length
and area. From the experiments it is shown that the recognition of molten pool using vision sensor
is an effective method.
Effect of Plasma Spraying Parameters on Anisotropic Feature of the Mechanical Property of Plasma Sprayed Al2O3 Coating
Authors: Adachi Shinichiro , Nakata Kazuhiro
Published: March 2009

The effects of the plasma spraying parameters on the strength of an Al2O3 coating were
investigated by changing the input electrical power to the plasma torch, the spray distance and the
Al2O3 powder size as the spraying parameters. The anisotropic feature of the coating strength is also
discussed. The strength of the Al2O3 coating in a direction perpendicular to a substrate plane was
dominated by the layered structure of Al2O3 splats, and was affected by all the parameters. The
strength of the coating in a direction parallel to the substrate plane was not affected by the input
electrical power. The strength of the former was lower than that of the latter, in the coating
containing many cracks. The anisotropy of the coating strength would be caused by the cracks
propagating along the lines of the laminated layer.
Effects of Different R Ratios on Fatigue Crack Growth in Laser Peened Friction Stir Welds
Authors: Hatamleh Omar , Hackel Lloyd , Forth Scott
Published: March 2009

The influence of laser peening on the fatigue crack growth behavior of friction stir welded
(FSW) Aluminum Alloy (AA) 7075-T7351 sheets was investigated. The surface modification resulting
from the peening process on the fatigue crack growth of FSW was assessed for two different R ratios.
The investigation indicated a significant decrease in fatigue crack growth rates resulting from using
laser shock peening compared with unpeened, welded and unwelded specimens. The slower fatigue
crack growth rate was attributed to the compressive residual stresses induced by the peening.
Long-Term Microhardness Evolution in Ti-Ni Shape Memory Alloys Processed by Severe Cold Rolling
Authors: Korotitskiy Andrey , Inaekyan K.E. , Brailovski Vladimir , Prokoshkin Sergey
Published: March 2009

Ti-50.26at.%Ni shape memory alloy samples were subjected to cold rolling (CR) with
true strains encompassing from moderate (logarithmic strain e=0.25) to severe (e=2.1) deformation.
СR with e = 0.5 and more initiated a partial austenite amorphization. The evaluation of structural
changes in the material during its long-term storage was performed using Vickers microhardness
(HV) technique. It was shown that during storage at room temperature up to 9 months,
microhardness varied following a dome-shaped trend, thus reflecting commonly encountered
interaction between two concurrent time-dependent phenomena, the first responsible for the
material hardening, and the second, for the material softening. To represent such phenomena, a
simple mathematical model was proposed and experimentally validated.
Multiscale Crystal Plasticity Simulation with Pseudo-Three-Dimensional Model on Ultrafine-Graining Based on Evolution of Dislocation Structures
Authors: Aoyagi Yoshiteru , Horibe Naohiro , Shizawa Kazuyuki
Published: March 2009

In this study, we develop a multiscale crystal plasticity model that represents evolution of
dislocation structure on formation process of ultrafine-grained metal based both on dislocation
patterning and geometrically necessary dislocation accumulation. A computation on the processes of
ultrafine-graining, i.e., generation of dislocation cell and subgrain patterns, evolution of dense
dislocation walls, its transition to micro-bands and lamellar dislocation structure and formation of
subdivision surrounded by high angle boundaries, is performed by use of the present model.
Dislocation patterning depending on activity of slip systems is reproduced introducing slip rate of
each slip system into reaction-diffusion equations governing self-organization of dislocation structure
and increasing immobilizing rate of dislocation with activation of the secondary slip system. In
addition, we investigate the effect of active slip systems to the processes of fine-graining by using the
pseudo-three-dimensional model with twelve slip systems of FCC metal.
Computer Simulation of Kinematics of Plastic Flow and the Deformed Condition of Metal at Processes Equal-Channel Angular Pressing
Authors: Belevich Aleksandr V. , Babin D.M.
Published: March 2009

Object of researches in the given paper is the technological process of obtaining from carbon
steel method equal-channel angular extrusion (ECAE) on one pass. The purpose of theoretical
research is the working of recomdations on projection of the process with the help of a designed
technique of simulation of process ECAE in CAE systems. Calculations were done under variable
conditions ECAE over the range changes of parameters: a corner of intersection of channels Ф from
90 up to 150 grades, speed of driving press from 0,05 m/s up to 0,2 m/s, temperature from 20°С up
to 600°С. As a result quantitative links of local parameters (stresses, strains and temperature) are
established with geometrical and technological ECAE parameters to one separate pass. Regularities
of change of parameters to ECAE process of cylindrical preforms in diameter of 20 mm and 30 mm
are established (steel 0,15%С), are investigated; character of change of a tension in the instrument
and power conditions of the process was studied.
Incremental ECAP of Plates
Authors: Olejnik Lech , Rosochowski Andrzej , Richert Maria W.
Published: March 2009

Batch severe plastic deformation (SPD) processes are mainly used for laboratory
purposes. More industrially oriented are continuous processes among which the new SPD process
of Incremental Equal Channel Angular Pressing (I-ECAP) is an attractive option. This paper
investigates the feasibility of using I-ECAP for nanostructuring of plates rather than bars. First, a
3D finite element simulation has been performed which shows the importance of restricting
material flow in the direction of plate width. A laboratory rig has been designed, which converts the
vertical movement of the machine crosshead into an oblique movement of the reciprocating punch.
Preliminary trials of I-ECAP have been carried out on a 4x30x100mm Al 1070 plate. Metallurgical
samples after 4 and 8 passes of I-ECAP (route A) have been investigated using TEM. In conclusion,
the new SPD process of I-ECAP is capable of processing plates, which opens up new possibilities
of nanostructuring metals on an industrial scale.
The Influence of ECAP Die Channel Geometry on Shear Strain and Deformation Uniformity
Authors: de A. Mendes Filho A.A. , Sordi Vitor Luiz , Rubert José Benaque , Ferrante Maurizio
Published: March 2009

The present work was performed in order to analyze the influence of the outer corner radius (R) of
ECAP die channels on the strain field of billets subjected to ECAP deformation in a Φ = 120o die,
employing three different methods: (i) physical simulation, consisting of the direct measurement of
deformations of a grid inscribed in longitudinally cut mid-planes of ECAPed billets; (ii) numerical
simulation employing an explicit finite element code for large displacements and large plastic
deformations, and (iii) calculation by the Iwahashi formula. Materials employed were Al-4%Cu and
an eutectic Pb-62Sn alloy, and the dependence of shear strain with R was satisfactorily described
using the three methods. The experimental method showed a small deviation from the other two,
which was explained making use of the corner die formation concept. Similarly, this concept helped
to understand the increase of strain heterogeneity with R. Also, it was shown that large corner radii
decrease ECAP pressing loads, facilitating deformation of high strength materials. Finally, the data
show that the deformation characteristics of the materials here studied do not exert a measurable
influence on the shear strain magnitude and distribution.
Microstructure and Mechanical Properties of Nanostructured Intermetallic Alloy Based on Ti2AlNb
Authors: Shagiev M.R. , Salishchev G.A.
Published: March 2009

Homogeneous nanocrystalline structure with the average grain size of about 300 nm was
produced in Ti2AlNb-based intermetallic alloy by a thermomechanical processing which included
multistep isothermal forging at temperatures below the β-transus and intermediate annealings.
Nanostructured material possessed excellent mechanical properties. At room temperature,
elongations up to 25% were obtained and the ultimate strength reached 1400 MPa. The alloy
exhibited superplastic behavior in the temperature range of 850-1000°C. The maximum elongation
of 930% and steady state flow stress σ50 of about 125 MPa were obtained at 900°C and strain rate of
4.2×10-3 s-1. The rolling temperatures of nanostructured alloy were defined from analysis of its
mechanical behavior at a typical rolling strain rate of about 10-1 s-1 and intermetallic sheets with
improved mechanical properties were produced.
Influence of Number of Passes in ECAP on Superplastic Behavior in a Magnesium Alloy
Authors: Figueiredo Roberto B. , Langdon Terence G.
Published: March 2009

Tensile tests were carried out at 473 K with initial strain rate of 10-4 s-1 in samples of a
ZK60 alloy (Mg-5.5% Zn-0.5% Zr) processed by different number of passes using Equal-Channel
Angular Pressing (ECAP). The measured superplastic elongations ranged from ~930% to a record
of ~3050%. The flow behavior was found to vary with the number of passes of ECAP. It is shown
that strain-hardening due to grain growth and the evolution of the strain rate sensitivity with the
strain determines the flow behavior and final elongations. The results are consistent with theories of
plastic flow in tensile testing.
Severe Plastic Deformation of Amorphous Alloys
Authors: Glezer Alex M. , Dobatkin Sergey V. , Plotnikova Margarita R. , Shalimova Anna V.
Published: March 2009

The structure and mechanical properties of amorphous alloy Ni44Fe29Co15Si2B10 after
severe plastic deformation (SPD) in Bridgman chamber at the different temperatures (77 and 298 K)
have been studied. It is shown that the early stages of the SPD of amorphous alloy cause a
noticeable decrease in microhardness HV and significant changes in the physical properties. With
increasing the value of SPD the transition from inhomogeneous to homogeneous (or to qualitatively
different) mode of plastic flow is observed, which is accompanied by the effects of homogeneous
nanocrystallization. The nanoparticle size does not exceed 10 nm. It is established that the thermally
activated nanocrystallization processes can occur at very low temperatures (77 K).
Features of the Structure Development and the Deformation Process in Zr-Based Alloys under Radial Forging
Authors: Perlovich Yuriy , Isaenkova Margarita , Grekhov M. , Krymskaya Olga , Fesenko Vladimir , Zavodchikov S. , Kotrekhov V.
Published: March 2009

Distinctive structure features of rods produced by hot and cold radial forging of a Zr-
2.5%Nb alloy were revealed. Most experimental data were obtained by X-ray methods. Among
considered aspects, connected with the undulatory mechanism of energy transfer, there are the
uniformity of bulk deformation, structure perfection under hot radial forging, the demolition of
secondary phases and the oversaturation of α-Zr with Nb under cold radial forging, the role of phase
transformations in deformation, and the suppression of recrystallization by annealing. Structure,
texture and properties of products, produced by radial forging from Zr-based alloys, allow to
consider this technology as an acceptable alternative to that usable nowadays.
TEM Studies on the Effect of Nature of Precipitates in Al-Li Alloy on Microstructural Evolution during Severe Plastic Deformation
Authors: Giribaskar Sivaswamy , Gouthama Gouthama , Prasad Rajesh
Published: March 2009

Equal channel angular extrusion (ECAE), involving intense plastic straining under high
applied pressure is generally recognized and extensively studied top down approach for producing
bulk ultra-fine grained (UFG) metallic materials, and even going down in size to the nanometer
range. In this research efforts are made to identify conditional under which grains with size less
than 100 nm form after ECAE. Evolution of microstructure of Al-Li based alloy processed by
ECAE is analyzed using transmission electron microscopy (TEM). Observations on the effect of
precipitates/second phase particles in the sample on the deformation characteristics and their role on
the increased degree of grain fragmentation process is highlighted. Samples of Al-Li based alloy
are solutionized, quenched and aged at different temperatures to obtain well formed precipitate
laths/plates before subjecting to ECAE. During the deformation process these precipitates
disintegrate into fragments and get dispersed into the Al matrix. The fragments of a few
nanometers size bring about drastic changes in the flow as well as the recovery characteristics of
processed samples. Evidence for dynamic recrystallisation taking place during the ECAE
processing is presented. It was observed that optimal thermal treatment leads to more effective
grain refinement and consequently an ultra-fine grained microstructure could be achieved even after
single pass in Al-Li based alloy containing precipitates and second phase particles.
Bulk Al Materials from Back Pressure Equal Channel Angular Consolidation of Mechanically Milled Particles
Authors: Kubota Masahiro , Wu Xiao Lin , Xu Wei , Xia Kenong
Published: March 2009

Mechanically milled pure aluminium powders were fabricated into bulk materials using
back pressure equal channel angular consolidation (BP-ECAC) for four or eight passes at 373K. The
bulk materials consolidated from 0 h and 4 h mechanically milled powders were characterised by
Vickers hardness tests and density measurements. Thermal stability of the consolidated bulk
materials was evaluated by isothermal heat treatments at 673K. The as-consolidated bulk material
from the 0 h milled (i.e. unmilled) powder showed nearly full density. However, full density was not
obtained with the 4 h milled powder even after eight passes. The HV values for the as-consolidated
materials fabricated from the 0 h and 4 h milled powders after four passes and from the 4 h milled
powder after eight passes were 57, 121 and 136, respectively. Softening was observed in the bulk
material consolidated from the 0 h milled powder during the isothermal heat treatment. However, the
hardness of the bulk materials consolidated from the 4 h milled powders after four and eight passes
increased to maximum values of 137 and 141 after heat treatment for 28 h and 8 h at 673K,
respectively. The maximum hardness was maintained for up to 100 h at 673K in both materials. The
hardening and thermal stability in the bulk materials from the milled powders are attributable to
dispersion strengthening of Al4C3 particles formed by solid-state reaction during the isothermal heat
treatment.
3D Tomographic EBSD Measurements of Heavily Deformed Ultra Fine Grained Cu-0.17wt%Zr Obtained from ECAP
Authors: Khorashadizadeh Anahita , Winning Myrjam , Raabe Dierk
Published: March 2009

Obtaining knowledge on the grain boundary topology in three dimensions is of great importance as
it controls the mechanical properties of polycrystalline materials. In this study, the three
dimensional texture and grain topology of as-deformed ultra fine grained Cu-0.17wt%Zr have been
investigated using three-dimensional orientation microscopy (3D electron backscattering diffraction,
EBSD) measurements in ultra fine grained Cu-0.17wt%Zr. Equal channel angular pressing was
used to produce the ultra fine grained structure.
The experiments were conducted using a dual-beam system for 3D-EBSD. The approach is realized
by a combination of a focused ion beam (FIB) unit for serial sectioning with high-resolution field
emission scanning electron microscopy equipped with EBSD.
The work demonstrates that the new 3D EBSD-FIB technique provides a new level of
microstructure information that cannot be achieved by conventional 2D-EBSD analysis.
Outstanding Mechanical Properties in the Materials with a Nano / Meso Hybrid Microstructure
Authors: Hiroshi Fujiwara , Nakatani Masashi , Yoshida Tetsufumi , Zhang Zhe , Ameyama Kei
Published: March 2009

Grain refinement is well known to influence the mechanical properties of materials,
especially the strength characteristics. The promising method for grain refinement is a SPD process
and it produces the homogenized nano grain material which exhibits very high strength and limited
ductility. Recently the grain refinement technique by the SPD in powder metallurgy (PM) field has
received much attention. The SPD-PM process is one of new processes combining mechanical
milling (MM) or alloying (MA), heat treatment and sintering processes. Microstructure of the
SPD-PM materials is easily controlled by the MM condition, and hence we can intentionally make a
heterogeneous microstructure. In the present study, commercially pure titanium, Ti-6Al-4V alloy
and SUS316L stainless steel powders are applied to the SPD-PM process. These MM powders are
sintered by Hot Roll Sintering (HRS) process. These SPD-PM materials demonstrate a
heterogeneous microstructure and high strength and advanced plastic strain. The microstructure of
materials consists of a shell and core hybrid microstructure, that is, a shell structure with nano
grains and a core structure with work-hardened coarse grains. All of the materials fabricated by
these processes demonstrate not only superior strength but also enough elongation. The mechanical
properties are strongly influenced by the shell / core microstructure. The nano / meso hybrid
microstructure by these processes has been proved to be very effective to improve mechanical
properties.
Effect of Grain Refinement on the Mechanical Behaviour of Ferritic Steels: Evolution of Isotropic Hardening and Kinematic Hardening
Authors: Bouaziz Olivier , Aouafi A. , Allain Sebastien
Published: March 2009

New experimental data related to the grain size and the Bauschinger effects have been
obtained for ferritic steels with grain size in the range of 3.5-22m. As the data show an increasing
contribution of the kinematic hardening with grain size refinement, a new physical based model
describing the isotropic hardening and the kinematic hardening is presented and validated with
regard to the grain size. The consequences are discussed for fine grain metallic alloys.
Regularities of Deformation and Fracture of Steels Subjected to Equal Channel Angular Pressing and Thermal Processing
Authors: Ivanov Afanasiy M. , Lukin Evgeny S. , Petrova Nurguyana D.
Published: March 2009

The article deals with the problems of strengthening and cold resistance increase of steels
through combining equal channel angular pressing (ECAP) with thermal processing (TP).
Dependence of cold resistance on the state of the material structure determined by regimes of equal
channel angular pressing and thermal processing is shown. Dependence of specific work of plastic
deformations, stored and dissipated energy of steel on its plasticity is stated.
Properties of UFG HSLA Steel Profiles Produced by Linear Flow Splitting
Authors: Bruder Enrico , Bohn Tilman , Müller Clemens
Published: March 2009

Linear flow splitting is a new cold forming process for the production of branched sheet
metal structures. It induces severe plastic strain in the processing zone which results in the
formation of an UFG microstructure and an increase in hardness and strength in the flanges. Inbuilt
deformation gradients in the processing zone lead to steep gradients in the microstructure and
mechanical properties. In the present paper the gradients in the UFG microstructure and the
mechanical properties of a HSLA steel (ZStE 500) processed by linear flow splitting are presented,
as well as a calculation of local strength from hardness measurements on the basis of the Ludwikequation.
In order to investigate the thermal stability of the UFG microstructure heat treatments
below the recrystallization temperature were chosen. The coarsening process and the development
of the low angle to high angle grain boundary ratio in the gradient UFG microstructure were
monitored by EBSD measurements. It is shown that heat treatment can lead to a grain refinement
due to a strong fragmentation of elongated grains while only little coarsening in the transverse
direction occurs. A smoothing of the gradients in the UFG microstructure as well as in the
mechanical properties is observed.
Severe Deformation of a Carbon Steel within the Ferritic Region
Authors: Eghbali Beitallah
Published: March 2009

The influence of severe warm deformation on the microstructural evolution and flow behavior of a
plain carbon steel has been investigated through torsion testing. The specimens were severe
deformed within the ferritic region up to strain of 70 with constant strain rate of 0.1 s 1 − .
Microstructural evolutions have been investigated using high resolution electron backscatter
diffraction (EBSD). True stress-true strain curves exhibit a single and smooth maximum, followed
by a slow but significant softening stage. A steady state is observed at very large strains. This
finding suggests that the relative balance between comparable work hardening and dynamic work
softening results in the occurrence of warm ductility during large deformation. The initial grain
structure was equiaxed, but at low strains the grains become elongated in the torsion direction.
However, at large strains the grain aspect ratio decreases and finally, further straining leads to the
formation of new fine grains with high-angle boundaries, which become more equiaxed than the
previous fragmented structure. The flow stress, as well as all the average microstructural
parameters, then remains independent of strain. The mechanisms operating during such warm flow
behavior and structure changes are discussed in detail.
Investigations on Deformation Behavior and Microstructure of Ultrafine Grained Two Phase Al-Mn Alloy Fabricated by Confined Channel Die Pressing
Authors: Mu Si Jia , Hu Wei Ping , Gottstein Günter
Published: March 2009

An ultra-fine grained Al-1.5Mn alloy was fabricated in an oversaturated and a precipitated
(Al6Mn particle) state by confined channel-die pressing (CCDP) at room temperature (RT).
Specimens for microcharacterization and mechanical tests were taken from the centre area of the
CCDP samples, where an equivalent strain of ε ≈1-1.4 was reached for one pass pressing. The
samples were subjected to CCDP for 1, 4, 8 and 16 passes, respectively. The microstructure evolution
during CCDP was investigated by transmission electron microscopy (TEM). The deformation
behaviour of the ultra-fine grained Al-Mn alloy after the CCDP process was determined by
compression tests at RT with different strain rates of ε& = 1× 10-4s-1, ε& = 5× 10-4s-1 and ε& = 1× 10-3s-1.
The results demonstrated that the alloy with Al6Mn precipitates had a larger grain size, higher yield
strength, a larger Hall-Petch coefficient, a stronger strain softening, a larger strain rate sensitivity and
a smaller activation volume after CCDP compared to the oversaturated alloy. These phenomena
indicate that second phase particles and solute element affect grain refinement and mechanical
behaviour during and after CCDP differently.