bluuebunny/crossref_metadata_2025 huggingface dataset:
Atomic Simulations on the Grain Subdivision of a Crystalline Metal
Authors: Shimokawa Tomotsugu , Kinari Toshiyasu , Shintaku Sukenori
Published: March 2009

The relationship between grain subdivision mechanisms of a crystalline metal and the strain
gradient under severe plastic deformation is studied by using molecular dynamics simulations in quasi
two dimensions. Two problems are simulated for single crystal models: (a) uniaxial tensile and
compressive deformation and (b) localized shear deformation. In the case of uniaxial deformation, a
large number of dislocation pairs with opposite Burgers vectors are generated under deformation, but
most dislocations are vanished due to pair annihilation under relaxation. Therefore, no dislocation
boundary can be formed. On the other hand, in case of localized shear deformation with large strain
gradient, dislocation boundaries are formed between undeformed and deformed regions. These
dislocations can be regarded as geometrically necessary dislocations. Consequently, the importance
of the strain gradient to make grain boundaries under plastic deformation can be confirmed by atomic
simulations.
Microstructural Stability of Duplex Stainless Steel Weldments
Authors: Dobránszky János , Ginsztler János
Published: March 2009

Welding experiences are demonstrated, which were developed on 2205 type duplex and
2509 type superduplex stainless steels (DSS and SDSS). The welded joints were produced by activated
TIG welding and laser beam welding. For the ATIG process, which is a special kind of the
TIG-welding, silica powder was used as activating flux. Microstructural characterizations were applied
for the measurement of ferrite/austenite phase ratio in the weldments. The welded joints were
thermally aged at temperature of 400 °C. The phase transformations produced during thermal ageing
were investigated by optical and scanning electron microscopy and thermoelectric power measurement.
Investigations show that the thermal ageing induced phase transformations are similar at
ATIG-welded weldment and DSS base material, but the incubation time is significantly shorter in
the weldment than in the base material when laser welding is applied.
Tribological Properties of Ni/Cu Multilayers
Authors: Hattori Tomoya , Kaneko Yoshihisa , Hashimoto Satoshi
Published: March 2009

Sliding wear and hardness tests in Ni/Cu multilayers electrodeposited on polycrystalline copper
substrate were carried out. The multilayers had a total thickness of 5 μm and an individual layer thickness
from 5 to 100 nm. Hardness of the multilayers measured with a nanoindentation tester was found to be
dependent on layer thickness. The multilayer with the layer thickness of 20 nm showed the highest value
among them. It was found that the wear resistances of all the multilayers tested were higher than that of an
electrodeposited nickel coating. It was also revealed that the specific wear rate of multilayers decreased with
decreasing the layer thickness although the highest hardness was attained at the 20 nm layer thickness.
Scanning ion microscope observation showed that the subsurface area kept the layered structure of nickel
and copper even after sliding wear. The multilayer had plasticity sufficient to accommodate deformation
coming from the sliding wear, because fine grains peculiar to severe plastic deformation process were
formed near the worm surface.
The Surface Analysis of Melted Arc Copper Beads
Authors: Wu Ying , Zhao Chang Zheng , Di Man , Gao Wei
Published: March 2009

Specific studies were carried out on the characteristic component from interior surfaces
(IS) of cavities in metallic fire debris by Auger electron spectroscopy (AES), especially in order to
distinguishing the primary and secondary electrical short circuit (ESC) arc beads. From the results of
AES, we can see that the components from interior surfaces of cavities in the primary and secondary
ESC are different, which help in probing the cause of the fire.
Microstructural Characterization and Temperature Analysis in Friction Stir Welding of A383/5052 Dissimilar Aluminum Alloys
Authors: Kokubo Masafumi , Kazui Shinichi , Kaneuchi Takao , Takayama Yoshimasa , Kato Hajime , Hirano Satoshi
Published: March 2009

Microstructural characterization and temperature analysis have been performed in friction
stir welding (FSW) of A383 and 5052 dissimilar aluminum alloys. Marked difference in
microstructure was observed between joints with different arrangements of materials. The
temperature at four points on each side of the joint line was measured during FSW in various
conditions. In addition, an analytical model assumed that the work generated by the rotation of the
tool led to the work for stirring materials and heat generation of the material and the tool. The
temperature of the retreating side (RS) for the joint of the advancing side (AS):A383/RS:5052 was
about 50K higher than that of AS, while the temperatures of AS and RS for the joint of
AS:5052/RS:A383 were almost the same. The experimental temperature could be calculated
reasonably by using the model with assumption of the work for stirring the material.
Defect Generation in Some Transition-Metal Silicides in Accommodating the Deviation from the Stoichiometric Compositions
Authors: Inui Haruyuki , Tanaka Katsushi , Kishida Kyosuke , Harada Shunta
Published: March 2009

The changes in microstructure and defect structure of two different semiconducting
transition-metal silicides, ReSi1.75 and Ru2Si3 with ternary alloying of substitutional elements with a
valence electron number different from that of the constituent metal have been investigated in order to
see if the crystal and defect structures of these silicides and thereby their physical properties can be
controlled through defect engineering according to the valence electron counting rule. The Si vacancy
concentration and its arrangement can be successfully controlled in ReSi1.75 while the relative
magnitude of the metal and silicon subcell dimensions in the chimney-ladder structures can be
successfully controlled in Ru2Si3.
Thermoelectric Properties of Ru2Si3-Based Chimney-Ladder Phases
Authors: Kishida Kyosuke , Ishida Akira , Tanaka Katsushi , Inui Haruyuki
Published: March 2009

The variations of the crystal structures and thermoelectric properties of the Ru1-xRexSiy
chimney-ladder phases were studied as a function of the Re concentration. A series of chimney-ladder
phases with a compositional formula of Ru1-xRexSi1.539+0.178x are formed in a wide compositional
range, 0.14 ≤ x ≤ 0.76. The composition of the chimney-ladder phase is systematically deviated from
the idealized composition satisfying the valence electron concentration rule: VEC=14. Measurements
of thermoelectric properties reveal that the chimney-ladder phases exhibit n-type semiconducting
behavior at low Re concentrations and p-type semiconducting behavior at high Re concentrations,
which are well consistent with the prediction based on the deviation of the composition of the
chimney-ladder phase from the idealized composition.
Study of Water-Debinding for Ceramic Parts by Injection Molding
Authors: Xie Zhi Peng , Wang Lin Lin , Yang Xian Feng
Published: March 2009

Water debinding is a new technique for ceramic injection molding. Compared with
conventional thermal debinding, water-debinding has many advantages, such as environment
friendly, high debinding rate, and suitable for molding large sized ceramic part. In this paper, binder
system, based on polyethylene glycol(PEG) and polyvinyl butyryl(PVB), was mixed with
3Y-TZP(ZrO2) powder, and feedstock with 54vol% of ceramic powders was obtained. Shear viscosity
of the feedstock was 300Pa·s at 190oC, when shear rate was 100/s, similar to the feedstock based on
paraffin wax(PW). SEM showed that the feedstock and sintered parts were both homogeneous. Water
debinding dynamics was also studied. For the 5mm x 6mm x 42mm sample, 65% of PEG could be
extracted within 2 hours in water at 40oC, and the bending strength of sintered compacts was above
900MPa. The samples with thickness from 9mm to 12mm were made and the green parts could be
debinded in water without any defects. The results showed water debinding method could increase the
debinding rate and was effective to fabricate large sized ceramic parts.
Grain Growth Behavior of Al2O3-ZrO2 with a Small Amount of Zirconia
Authors: Nagashima M. , Hayakawa Motozo
Published: March 2009

Grain growth behavior in Al2O3 with a small amount of ZrO2 (< 5 vol%) was examined.
Grain growth of Al2O3 was retarded by zirconia particles, despite the small amount of added
zirconia. The fraction of the zirconia particles embedded within alumina grains (intragranular
zirconia particles) increased with decreasing zirconia content and increasing sintering temperature.
Grain growth inhibition of alumina in the Al2O3-ZrO2 showed good agreement with the prediction
of modified Zener’s pinning effect by the zirconia particles on grain boundaries.
A Pressured Steam Jet Approach to Tool Wear Minimization in Cutting of Metal Matrix Composites
Authors: Anjaiah D. , Shetty Raviraj , Pai R. , Kini M.V. , Rao S.S.
Published: March 2009

Metal matrix composites (MMCs) have been found to possess tremendous prospective
engineering applications that require materials offering a combination of lightweight with
considerably enhanced mechanical and physical properties. However, the applications of MMCs are
limited by their poor machinability which is a result of their highly abrasive nature that causes
excessive wear to the cutting tools. In this study, an investigation into the mechanism of the tool
wear in cutting of MMCs is carried out. It is found that during cutting of an MMC, the tool cutting
edge will impact on the reinforcement particles. The impacted particles will then either be dislodged
from the matrix, doing no harm to the tool, or be embedded into the matrix, ploughing on the tool
flank and causing excessive tool flank wear. According to this tool wear mechanism, a pressured
steam jet approach is developed for the minimization of the tool wear by preventing the impacted
reinforcement particles from being embedded in the workpiece matrix. Experimental tests for
cutting of SiC–aluminum MMC using cubic boron nitride (KB-90) and polycrystalline diamond
(KP-300) tool inserts with the aid of the pressured steam jet are conducted. The results show that
from full factorial design of experiments the effect of the pressured steam jet plays a significant role
on the tool wear followed by tool inserts and depth of cut. The working mechanism of the pressured
steam jet method and the experimental testing results are discussed in detail.
Fabrication of Polystyrene Fibers Containing Nanoparticles of TiO2 and ZnO by Electrospinning
Authors: Kobayashi Mikihiko , Egashira Mitsuru , Konno Takeshi
Published: March 2009

Polystyrene fibers were fabricated by electrospinning. Polystyrene resin was dissolved in
chloroform, N,N-dimethylformamide, or their mixtures. In experiments with 10 wt-% solutions of
polystyrene in various solvents, a 1:1 solvent mixture was found to be optimal. In the 1:1 solvent, an
increase in polystyrene concentration resulted in a decrease in the number of beads on the electrospun
fibers and an increase in their diameter. A 20 wt% solution of polystyrene gave fibers with a diameter
of about 1.8 $m with almost no beads. Polystyrene fibers containing nanoparticles were prepared by
electrospinning 20 wt% polystyrene solutions containing dispersed nanoparticles of TiO2 or ZnO. The
concentrations of nanoparticles in the electrospun fibers, determined by energy dispersive X-ray
spectroscopic analysis, were less than expected.
Fabrication of Nanostructured Materials by Hydrostatic Extrusion: Advantages and Limitations
Authors: Kurzydlowski Krzysztof Jan , Lewandowska Małgorzata
Published: March 2009

A growing interest in nanostructured materials brought about development of their
fabrication methods. A great interest has been paid in this context to the methods of grain
refinement which can be induced by plastic deformation. Hydrostatic extrusion was recently
proposed as an alternative method of grain size reduction down to nanometer scale in metallic
materials. The aim of the present contribution is to describe, in a systematic way, advantages of this
processing method, such as the possibility of processing hard-to-deform materials and obtaining
large dimesions products. Special attention was given to the role of hydrostatic pressure and the
effectiveness of the process in terms of grain refinement and high angle grain boundaries formation.
Limitations of hydrostatic extrusion, such as restriction on strain in one pass and morphological
texture are also discussed together with possibilities of their overcoming.
Application of PEG/PMMA Binder for Powder Injection Moulding of Hardmetals
Authors: Chuankrerkkul Nutthita , Davies Hywel A. , Messer Peter F.
Published: March 2009

Powder injection moulding (PIM) is a cost effective powder metallurgical process for the
fabrication of small, complex-shaped components for high performance applications. A binder
system, which comprises a major fraction of polyethylene glycol (PEG) and a minor fraction of a
very finely dispersed polymethyl methacrylate (PMMA), has been applied for tungsten carbide
(WC) – cobalt (Co) hardmetal powders. PEG can be removed rapidly by water leaching and PMMA
is removed by subsequent pyrolysis when the components are ramped up to the sintering
temperature. In this work, the development of feedstock formulations and of the processing
parameters for a successful injection moulding and to achieve high density has been investigated.
The present study has demonstrated that the binder can be employed for the production of WC-Co
hardmetal components by PIM process. The maximum density achieved thus far is 97% of the
theoretical value.
Microstructure and Mechanical Property of Al2O3/Y3Al5O12 (YAG) Eutectic Ceramic In Situ Composite Prepared by Laser Zone Melting
Authors: Su Hai Jun , Zhang Jun , Liu Lin , Fu Heng Zhi
Published: March 2009

Directionally solidified Alumina-based eutectic ceramic in situ composite is a kind of
promising candidate for high temperature structural material applied at elevated temperature above
1923K because of its excellent properties. With laser zone melting directional solidification,
Al2O3/Y3Al5O12 (YAG) eutectic ceramics are successfully prepared. The relationship between the
eutectic microstructure and the processing parameter is studied, and the mechanical property of the
composite is measured. The results show that: (1) Laser power density and scanning rate strongly
affect the eutectic microstructure. With proper processing parameters adjusted, the binary lamellar
eutectic microstructure is obtained, in which Al2O3 and YAG phases are three-dimensionally coupled
and continuously connected without grain boundaries and amorphous interface phases. (2) The
eutectic spacing decreases to about 1μm with increasing scanning rate. (3) The maximum hardness of
19.5GPa and the room fracture toughness of 3.6MPa.m1/2 are obtained by Vickers indentation
measurement.
Hot Explosive Compaction of Udimet 700 Powder
Authors: Prümmer Rolf , Witt A.
Published: March 2009

Hot isostatic pressing (HIP) is the established procedure to process Udimet 700 Powder by Powder Metallurgy (P/M) techniques. In this paper the method of hot explosive pressing (HEP) was applied. Its main feature is the direct method of explosive pressing. To avoid any reaction beforehand, the heating device and the explosive compaction device are separated and brought together very rapidly just a few milliseconds before ignition of the explosive charge. Udimet 700 bulk samples are obtained and investigated by metallographic and mechanical testing.
Processing of Advanced Materials Using Conventional and Shock Techniques
Authors: Mamalis A.G.
Published: March 2009

Some of the activities of the Laboratory of Manufacturing Technology of the NTUA in
manufacturing engineering are reported, focusing onto some recent trends and developments in
advanced manufacturing of advanced materials, in the important engineering topics nowadays from
industrial, research and academic point of view: nanotechnology/nanostructured materials,
synthesis and net-shape fabrication of superconductors, biomedical engineering and solar energy
devices.
Behaviors of High Explosive near the Critical Conditions for Shock Initiation of Detonation
Authors: Kubota Shiro , Ogata Yuji , Wada Yuji , Saburi Tei , Nagayama Kunihito
Published: March 2009

The behaviors of the high explosive near the critical conditions for shock initiation of
detonation are investigated by high speed photography and pressure measurements in gap tests. The
sample is RDX base explosive, and the inner diameter of donor and acceptor charges is 26 mm. Gap
material is PMMA. Near the critical condition, the results under the following conditions have been
discussed. 1) Shock to detonation transition (SDT) take place in acceptor, 2) The SDT does not occur,
but the reaction wave affects the leading shock front in acceptor, and 3) The gap length in which the
effect of the reaction wave to shock front almost disappears. These results are very useful to construct
the initiation model for solid explosive.
Dependence of Blast Attenuation on Weight of Barrier Materials
Authors: Homae Tomotaka , Wakabayashi Kunihiko , Matsumura Tomoharu , Nakayama Yoshio
Published: March 2009

The attenuation effect of barrier materials, which covers an explosive completely, on blast
waves was studied. The density of the barrier materials was examined to make the barrier materials
light and low in volume. Water gel, small spheres of foam polystyrene, and mixtures of these two
materials were used as the barrier materials, and the density of the mixture was varied from 0.12
g•cm-3 to 1.0 g•cm-3 by changing the mixed volume ratio. Natural silica sand was also tested for
comparison. A spherical PMMA container was filled with the barrier materials and a spherical
pentolite (100 g) was ignited at the center of container. The blast pressure around the container was
measured. The mixture of the density of approximately 0.55 g•cm-3 maximized the attenuation of the
blast wave for the same volume. The attenuation effect depends not only on the weight of the barrier
materials but also on the porosity. A mixture of a density of approximately 0.13 g•cm-3 maximized the
attenuation of the blast wave for the same weight. Using porous materials, relatively light barrier
materials can attenuate the blast wave effectively, if the volume is not restricted. The attenuation
effect of sand was greater than that of water gel and a mixture for the same volume.
Effect on Aqua Quenching of Spring Steel (JIS SUP 9)
Authors: Lee Sang Sik , Lee Choong Ho , Cho Young Tae
Published: March 2009

Si-Mn spring steel (JIS SUP 9) is primarily employed in the construction of coil springs,
particularly those used in soil cultivators deployed in harsh environments. This is due to its specific
properties, which allow it to resist permanent deformation, and also provide rapid and effective
vibration relief. Si-Mn spring steel (JIS SUP 9) for use in such projects is normally subjected to oil
quenching and heat treatment, in order to strengthen its resistance to both impact and fatigue.
Unfortunately, oil quenching is associated with environmental issues, most notably pollution and the
contamination of wastewater with oil. Therefore, the objective of this study was to describe an
alternative aqua quenching for use with this heat treatment. However, aqua quenching has
traditionally conferred a lower tensile laod than does oil quenching. This problem of lesser tensile
load was solved by properly controlling the density and temperature of the aqua quenching liquid, as
well as careful mixing. As a result, it has proven possible to achieve results with aqua similar to those
conferred by oil quenching, with regard to chemical components, tensile load, and surface hardness.
The tensile load results achieved by oil quenching were 13,145 Pa and 17,177 Pa, and the tensile
loads achieved with aqua quenching were 15,392 Pa, 16,804 Pa, 17,923 Pa, and 18,668 Pa. Therefore,
the results of our experiments demonstrated the appropriacy and efficacy of this aqua quenching
technique as a component of heat treatment for Si-Mn spring steel (JIS SUP 9).
Collection of Product Synthesized Using Extremely High Impulsive Pressure Generator
Authors: Kira Akio , Hokamoto Kazuyuki , Ujimoto Yasuhiro , Kai Shoichiro , Fujita Masahiro
Published: March 2009

A new method has been developed to generate an extremely high impulsive pressure by
using a metal jet that is discharged when a metal collides with another metal. The high pressure is
used to synthesize a new material. When a metal plate was accelerated by the detonation of an
explosive, it collides with the concentric circle of the conic surface of a conical concave metal block
metal jets are discharged from all parts on the concentric circle. The metal jets fly toward the center
while converging and collide with each other at the central axis. Because those collide at high-speed
pressure becomes extremely high. The flight direction of the converged metal jet changes
downward. The metal jet collides with the bottom of the block. A large hole is formed inside the
bottom. The formation process of the hole was examined by the observation of the section of the
block. A specimen powder that was rubbed to the conic surface is discharged with the metal jet and
become the high pressure. The specimen powder is synthesized to a different material. The
synthesized material is held inside the formed hole. The existence of cBN was confirmed by the
X-ray diffraction of the synthesized material, in the case that BN was used as the specimen powder.
Similarly, the existence of diamond was confirmed in the case of graphite powder.
The Formation of Onions at Shock-Wave Loading of Graphite
Authors: Blank V.D. , Deribas A.A. , Kulnitsky B.A. , Perezhogin I.A. , Utkin A.V.
Published: March 2009

The results of experiments with shock – loading of graphite bar by sliding detonation wave
of HE are presented in this paper. It were revealed the nano – sized onions at the SEM investigation in
the preserved sample of Graphite. The estimation of the values of pressures of shock – loading
permits to assume that the observed structures were formed directly by solid – solid transformation.
Behaviour of Cellular Structures under Impact Loading a Computational Study
Authors: Ren Zoran , Vesenjak Matej , Öchsner Andreas
Published: March 2009

New multiphysical computational models for simulation of regular open and closed-cell cellular structures behaviour under compressive impact loading are presented. The behaviour of cellular structures with fluid fillers under uniaxial impact loading and large deformations has been analyzed with the explicit nonlinear finite element code LS-DYNA. The behaviour of closed-cell cellular structure has been evaluated with the use of the representative volume element, where the influence of residual gas inside the closed pores has been studied. Open-cell cellular structure was modelled as a whole to properly account for considered fluid flow through the cells, which significantly influences macroscopic behaviour of cellular structure. The fluid has been modelled by applying a Smoothed Particle Hydrodynamics (SPH) method. Computational simulations showed that the base material has the highest influence on the behaviour of cellular structures under impact conditions. The increase of the relative density and strain rate results in increase of the cellular structure stiffness. Parametrical numerical simulations have also confirmed that filler influences the macroscopic behaviour of the cellular structures which depends on the loading type and the size of the cellular structure. In open-cell cellular structures with higher filler viscosity and higher relative density, increased impact energy absorption has been observed.
Numerical Prediction on Cookoff Explosion of Explosive under Strong Confinement
Authors: Liu Zhi Yue , Suceska Muhamed
Published: March 2009

The cookoff of explosives is of great concern for the safety assurance of explosive
devices in storage, transportation and handling. It may occur in the situation that explosive devices
are subjected to the external heating stimuli such as fire or high-temperature surrounding. In order
to gain ever-increasing knowledge toward the cookoff explosion of explosives, we establish
numerical program to predict the cookoff explosion of explosive in a metal container. The
computational formulation and methods are given in detail. The thermal decomposition and
temperature variation in the interior of explosive were found corresponding to several typical
external heating conditions. The results demonstrate that the method is beneficial to the future study
on this subject.
Cyclic Stress in 316L Austenitic Stainless Steel at Low Temperatures
Authors: Polák Jaroslav , Petrenec Martin , Man Jiří
Published: March 2009

Austenitic stainless steel was cycled at a series of temperatures in the interval from 296 K
to 113 K. Constant plastic strain amplitude loading at different levels of plastic strain amplitude and
testing similar to multiple step test method were applied at different temperatures. The stress
amplitude was continually recorded and selected hysteresis loops were stored and later analyzed
using statistical theory of the hysteresis loop. Effective stress component and probability density
function as a function of temperature were evaluated. The results were discussed in terms of the
temperature dependence of the cyclic yield stress and its sources.
The Effect of Lüders' Flow on Brittle Fracture Initiation in Pearlitic Steel
Authors: Dlouhý Ivo , Jurášek Ladislav , Holzmann Miloslav
Published: March 2009

In pearlitic steels the fracture initiation of pre-cracked specimens is strongly affected by
Lüders’ flow and higher strength properties. There is a gap in fracture toughness data of pre-cracked
Charpy (PC) and compact tension (CT) specimens between 60 and 90 MPam1/2 due to plastic hinge
formation. The distribution of maximum principal stress ahead of the crack tip in PC specimen
loaded into fully plastic regime was found to be identical with that of reference stress-strain field in
plane-strain SSY condition. 3D FEM simulations have also shown that there is no constraint loss in
PC specimens.
Investigation of Cu/Al Metal Laminates Prepared by Plasma Activated Sintering (PAS)
Authors: Guo Ya Jie , Lin Jian Ping , Qiao Guan Jun , Jin Hai Yun
Published: March 2009

Copper and aluminium laminates are alternately stacked and sintered by PAS at T=743K under different pressures. Microstructure of the cross section of the samples are characterized and analyzed by means of Optical Microscope (OM), Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscope (EDS). The results show that the initial Al layers melted and produced Al-rich liquid phase during sintering at T=743K, and the Al-rich liquid phase ultimately formed complicated L layer consisting of the saturated solid solution phase Al(Cu) and the two-phase Al2Cu-Al(Cu) eutectic when the laminates was cooled to room-temperature. The interface between the Cu layer the L layer consists of solid solution(α), Al2Cu3(δ)and Al2Cu(θ) layer. Voids and cracks are not found at or near the interfaces of the polished samples. The most important effect of the pressure is to change the shapes of interfaces, which almost smooth at 10MPa but flexual at 50MPa.
The Effect of Mixed Abrasive Slurry on CMP of 6H-SiC Substrate
Authors: Lee Ho Jun , Park Boum Young , Lee Hyun Seop , Jeong Suk Hoon , Seo Heon Deok , Joo Suk Bae , Jeong Hae Do , Kim Hyoung Jae
Published: March 2009

Silicon carbide (SiC) is a wide band gap semiconductor being developed for high
temperature, high power, and high frequency device applications. For the manufacturing of SiC to
semiconductor substrate, many researchers have studied on the subject of SiC polishing. However,
SiC faces many challenges for wafer preparation prior to epitaxial growth due to its high hardness and
remarkable chemical inertness. A smooth and defect free substrate surface is important for obtaining
good epitaxial layers. Therefore, hybrid process, chemical mechanical polishing (CMP) has been
proposed to achieve epi-ready surface.
In this paper, the material removal rate (MRR) is investigated to recognize how long the CMP
process continues to remove a damaged layer by mechanical polishing using 100 nm sized diamond,
and the authors tried to find the dependency of mechanical factors such as pressure, velocity and
abrasive concentration using single abrasive slurry (SAS). Especially, the authors tried to get an
epi-ready surface with mixed abrasive slurry (MAS). The addition of the 25nm sized diamond in
MAS provided strong synergy between mechanical and chemical effects resulting in low subsurface
damage. Through experiments with SAS and MAS, it was found that chemical effect (KOH based)
was essential and atomic-bit mechanical removal was efficient to remove residual scratches in MAS.
This paper concluded that SiC CMP mechanism was quite different from that of relatively soft
material to achieve both of high quality surface and MRR.
Dry Sliding Wear Characteristics of Ti-Nb-Si Alloys for Biomedical Application
Authors: Kim Sun Ki , Kim Han Sol , Kim Won Yong
Published: March 2009

This study is to examine wear properties of Ti-Nb-Si alloys under dry condition and to
investigate its wear mechanism. A ball-on-disc type wear testing machine was used to evaluate the
wear factor. Optical microstructure observation revealed that the microstructure appeared to mixture
appearance consisting of β phase and small amount of α″ martensite phase. Yield strength increased
with increasing Nb and Si content. Wear resistance of the present alloy are strongly dependent upon
yield strength and elastic modulus. Energy dispersive spectroscopy (EDS) and X-ray diffraction
(XRD) analysis confirmed the tribo-chemical reaction between the alumina ball and the present alloy
occurs due to decomposition of alumina to aluminum.
Crystallization Kinetics for Synthesis Hyper-Structure in P2O5-ZnO-B2O3-BaO-Al2O3-TiO2 Glass Ceramic Composite
Authors: Kim Young Seok , Lee Kyu Ho , Kim Tae Ho , Jung Young Joon , Yim S. H. , Ryu Bong Ki
Published: March 2009

The nucleation and crystallization kinetics of P2O5-B2O3-ZnO-BaO-Al2O3-TiO2 crystals in bulk glass in which this crystals were found to crystallize in the heating process of the glass, were studied by non-isothermal measurements using differential thermal analysis (DTA). A nucleation rate-temperature was determined by plotting either the reciprocal of the temperature corresponding to the crystallization peak maximum, 1/Tp, or the height of the crystallization peak, (*T)p, as a function of nucleation temperature, Tn. The temperature where nucleation can occur for this glass ranges from 700°C to 890°C and the temperature for maximum nucleation is 760±5°C. The correct activation energy for crystallization, Ec, for this glass is the same for surface and/or bulk crystallization, and is 533±15°CkJ/mol. The analysis of the crystallization data with the Kissinger equation and the Marotta equation yields the correct value for Ec only crystal growth occurs on a fixed number of nuclei. The crystallization process of a sample heat treated at the temperature of the maximum nucleation rate was fitted to kinetic equations with an Avrami constant, n ≈2 and a dimensionality of crystal growth, m ≈2.
Mechanical and Electrical Properties of Ga-Doped ZnO Films Deposited on Flexible Substrate by DC Magnetron Sputtering
Authors: Lee Dong Yeop , Lee Jung Rak , Kim Do Geun , Lee Gun Hwan , Kim Young Seok , Song Pung Keun
Published: March 2009

Ga-doped ZnO films were deposited on polyethylene terephthalate (PET) substrate by dc
magnetron sputtering using a high density GZO target (doped with 6.65 wt% Ga2O3) without
substrate heating. We investigated electrical, structural, and mechanical properties of GZO films
deposited under various total gas pressures (Ptot). GZO films deposited at Ptot of 2.0 Pa showed the
lowest resistivity (2.91 x 10-2 7cm), which could be attributed to higher crystallinity of the film. Also,
this GZO film showed the lowest change in resistance (8 R/R0 = 0.3) for the dynamic bending test.
Preparation and Characteristics of Eu and Dy Doped Sr4Al14O25 Phosphor
Authors: Luitel Hom Nath , Watari Takanori , Torikai Toshio , Yada Mitsunori
Published: March 2009

Sr4Al14O25:Eu2+, Dy3+ long persistent phosphors with different B, Eu and Dy contents were prepared by solid phase reaction at various temperatures in H2/N2=1/9 atmosphere. X- ray diffraction and scanning electron microscopy observations showed that, when the phosphor was doped with 40 at% B, single dense Sr4Al14O25 phase was formed but for the samples with less than 40 at% B, mixed phases containing SrAl12O19 and SrAl2O4 were observed while for higher B content (100 at%) SrAl2B2O7 phases appeared. The phosphor showed emission peak centered at 500 nm with blue green color. When 40 at% of H3BO3 was added and doped with 4 at% of Eu and 8 at% of Dy, it showed the maximum initial intensity of 3170 mcd.m-2 and the longest persistency which is greater than 20 h over value of 5 mcd.m-2.
Preparation of Ultrafine TiO2 Nanofibers and their Application in Removal of NOx in Air
Authors: Juengsuwattananon Kannikar , Rujitanaroj Pim On , Supaphol Pitt , Pimpha Nuttaporn , Matsuzawa Sadao
Published: March 2009

Titanium dioxide nanofibers were fabricated by electrospinning technique. The titania
solutions were obtained from adding various types of Ti precursor (Ti(OBu)4, Ti(OiPr)4, and
Ti(OPr)4) to an ethanol solution containing polyvinyl pyrrolidone (PVP). Acetic acid was used to
stabilize the solution and to control the hydrolysis reaction. The porous and well-defined crystalline
structure was obtained after calcined at 450oC for 1 h. The thermal behavior, phase composition
including crystallite size, as well as the morphology of as-synthesized nanofibers was obtained from
thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM)
and transmission electron microscopy (TEM), respectively. The average diameter of these nanofibers
was in the range from 100 to 400 nm depending on titania precursor. The photocatalytic activity of
TiO2 fibers were evaluated for NOx degradation in a gaseous phase. The results demonstrated that at
the same catalyst loading, the photocatalytic activity of TiO2 nanofiber was higher than the
commercial Degussa P-25.
Comparative Study on TiH2 and CaCO3 for Fabrication of Mg Alloy Foams
Authors: Seo Chang Hwan , Jeong M. J. , Jung In Young , Hur Bo Young
Published: March 2009

Aluminum alloy foams, new materials belonging to a special class of porous materials,
have been prepared using melt foaming method. Silicon was chosen alloying element due to its low
density, high strength, effective casting and reduced shrinkage. Melt foaming method is cost-effective
method to fabricate metal foam. Usually, TiH2 is applied to blowing agent, but its cost is high. CaCO3
is one of candidates to substitute TiH2 in the economic view-point. For the comparison of formability,
Mg alloy foams were prepared by TiH2 and CaCO3. However, the decomposition temperature of
CaCO3 is higher than that of TiH2. This paper will be discussed on the possible usage of CaCO3 in the
Al melt.
Concentration of Organic Acid from Fermented Food Wastes Using a MF/RO Process
Authors: Lee Jin Woo , Kim Jong Oh , Jung Jong Tae
Published: March 2009

The amount of food waste has been increasing every year. Food waste takes relativity
high portion of domestic waste and we have much difficulty in treating it. Most of food wastes are
landfilled or incinerated after drying for the reduction of water content. The operation cost of the
landfill and the incineration are very high. To solve the landfill and the incineration problems in
recent years, the recycling of food waste was used by the methods of turning food waste into animal
food and fertilizer. Food wastes are compatible to be used as feedstock of the fermentation because
they contain valuable nutrients. Among these situations, organic acids, which are effectively used in
a variety of industrial processes, can be considered to be a high cost value-added products. The
purpose of this study is to evaluate the possibility of organic acid concentration using a MF/RO
system. A MF/RO system was believed to be an effective one for the concentration of organic acid
from food waste. Water quality of fermentation broth, MF permeate and RO retentate in terms of
conductivity, pH, electric conductivity, TS (Total solids), TDS (Total dissolved solids), CODcr
concentration, chloride ion concentration was examined as analytic items. pH of fermentation broth
was higher than that of MF permeate and RO retentate due to the concentration of organic acid. pH
of RO retentate was about 4. Conductivity, TDS, CODCr and chloride ion of RO retentate were
about 1.3, 1.3, 2.9, 4.5 times higher than that of fermentation broth, respectively and TS reduced
about 0.8 times. This may be ascribed to separate effectively the solid-liquid separation by MF and
RO rejection. Consequently, a MF/RO system is believed to be applicable for the concentration of
organic acid from fermentation broth of food waste.
Effects of Al Addition on Mechanical Properties of Plasma Spayed Al2O3-Al Composite Coatings
Authors: Yin Zhi Jian , Tao Shun Yan , Zhou Xia Ming , Ding Chuan Xian
Published: March 2009

In this work, Al2O3-Al composite coatings with different compositions (Al2O3-5wt.% Al,
Al2O3-10wt.% Al and Al2O3-15wt.% Al) were deposited by plasma spraying. The effect of Al
addition on the mechanical properties of coatings was explored in terms of microhardness, fracture
toughness and sliding wear rate. An additional statistical study of Weibull analysis was carried out for
further investigating the mechanical data variation. The increase in Al addition was realized to show
little effects to decrease porosity of coatings. With the increase in Al addition, the microhardness of
coatings decreased from 869 to 742 Hν0.2 along with larger fluctuation in microhardness values
indicated by lower Weibull modulus (5.7-10), whereas toughness of coatings was improved ranging
from 2.7 to 4.1 MPa.m1/2. Friction tests showed that the Al additions effectively contribute to
decrease the friction coefficient of coatings sliding against steel counterpart. Among various
coatings, the Al2O3-15wt.% Al coating exhibits lowest friction coefficient but worst wear resistance.
This may arise due to its significantly decreased microhardness.
Machinability and Microstructure of SiC/h-BN Nano-Composites
Authors: Jin Hai Yun , Qiao Guan Jun , Peng Zong Ren , Gao Ji Qiang
Published: March 2009

SiC particles coated with nano-BN were synthesized and the machinable SiC/BN ceramic
nano-composites were fabricated by Plasma Active Sintering (PAS) in N2 atmosphere. The existing
and distribution of h-BN phase were revealed by X-ray diffraction (XRD), and SEM. For the existing
of weak interface between h-BN and SiC grains, the machinability of both SiC/BN micro-composites
and nano-composites were improved obviously. Because the nano-sized h-BN crystals were
homogeneously dispersed around the SiC grains of the matrix, the fracture strength of the
nano-composites was better than the SiC/h-BN micro-composite.
Shape and Size Dependent Melting Point Temperature of Nanoparticles
Authors: Gupta Sanjeev K. , Talati Mina , Jha Prafulla K.
Published: March 2009

The present paper reports a simple calculation of the size and shape dependent melting temperature of nanoparticles. The melting temperature of any nanoparticle basically depends on the ratio of surface atoms to the total atoms. Significant melting temperature suppression is observed when the particle size approaches the sub-20 nm range. The behavior of melting temperature is similar for the larger nanoparticles of all considered shapes but differs significantly for small nanoparticles. Different melting temperature is predicted for the nanoparticles of the same size in different shapes.
Development of Intergranular Stresses during In Situ Compression Tests in Zircaloy-4
Authors: Zanellato O. , Fitzpatrick Michael E. , Daymond Mark R. , Edwards Lyndon , Turski Mark
Published: March 2009

This paper reports results of an in-situ compression experiment carried out on a hot rolled
Zircaloy-4 plate at ENGIN-X, ISIS. The experiment was aimed at characterizing the plastic
anisotropy of the alloy, which can give rise to high intergranular stresses in the polycrystal. As
expected from the crystal anisotropy, the various lattice reflections had very different behaviours. In
the compression directions, the basal <0002> reflections appeared to bear much more load than the
other planes. The resulting intergranular elastic strains could therefore reach up to 5000 microstrain
after 10% total deformation, and were responsible for high type II residual stresses after unloading.
Considering the macroscopic behaviour, the normal direction had higher mechanical properties than
the other two processing directions. The strong texture measured from EBSD measurements suggest
that the crystal anisotropy has been brought to a macroscopic level. The experiment also evidenced
a significant change in texture for compression along the rolling direction which indicates twinning
activation.
Monte Carlo Simulation to Macro Stress Evaluation and Micro Strain Analysis by Neutron and Synchrotron Radiation Diffraction
Authors: Sprauel Jean Michel
Published: March 2009

Neutron and synchrotron strain or stress evaluations are reliable when the probe volume
is completely immersed in the studied material. However, acquisitions carried out close to
interfaces are much more difficult to analyze. Under these conditions, it is indeed very difficult to
characterize precisely the volume analyzed by the radiation and finally to define the measured
depth. To solve this problem, a complete Monte Carlo simulation of neutron spectrometers and
synchrotron experiments has been developed. This method allows defining precisely the size and
shape of the probe used. It permits then predicting the evolution of the diffracted intensity versus
the position of this volume in the matter. The calculations finally let to define the real analyzed
depth, accounting for the local conditions of diffraction and absorption in the material. The method
is illustrated by neutron and synchrotron experiments carried out to characterize stress fields
existing close to interfaces. The simulations also permit predicting the shape of diffraction profiles
that would be observed on perfect specimens. Such information can then be used to correct the
instrumental broadening existing in real experiments. This allows a fine Fourier analysis of the
diffraction peaks recorded for several orders of reflection and finally permits defining the mean size
of the crystallites and the root mean squares of the strains of second and third kind. Such
information is useful to characterize and analyze the mechanical behavior of materials.
Analysis of Residual Stresses Around ‘Dimpled’ Cold-Expanded Holes in Aluminium Alloy Plates
Authors: Zhang Shu Yan , Schlipf Jordan , Korsunsky Alexander M.
Published: March 2009

A traditional approach to increasing fatigue resistance of many assemblies involves the
creation of regions of compressive residual stress. For example, riveting holes used in modern
passenger aircraft are currently subjected to cold expansion using split mandrel tools. The method is
relatively expensive and not entirely problem-free. In the present study we consider a method of
creating residual stresses around drilled holes referred to as ‘dimpling’, that itself is a variation of a
novel technique known as the StressWaveTM process. An experimental procedure is described for
the creation of localised regions of significant plastic deformation and residual stress by ‘dimpling’,
allowing the production of cold-worked and residually-stressed specimens. The overall aims of this
study were to determine thickness-average residual stresses by two different techniques, namely,
one destructive technique (Sachs boring) and one non-destructive (high energy X-ray diffraction);
and to compare the results. In Sachs boring experiments the variation of strain gauge readings with
increasing diameter of the central hole was recorded. A classical elastic-ideally plastic axisymmetric
model for plane stress conditions was used in the analysis. Energy dispersive synchrotron X-ray
diffraction experiments were performed for non-destructive assessment of residual elastic strains.
The two different stress evaluation techniques used in this project led to consistent results. Good
correlation was found between the stresses obtained from X-ray diffraction results and those
deduced from Sachs boring experiments.
Mechanical and Physical Analysis of Alloys Samples Produced with a New High Centrifugal Rate Machine
Authors: Lopez I. , Benmarouane Abdelilah , Bonnefoy Herve , Millet Pierre , Lodini Alain
Published: March 2009

A full review for technological processes used today, in dental prostheses industry for titanium casting,
both in Europe and in United States, reveal that, there is no equipment available on the market able to
cast small titanium parts in secondary inert vacuum by induction melting and centrifugal casting. All
these advanced processes together contribute to an original concept of the Denticast System. The
computer controlled cast sequence is another important factor contributing to a robust system, able to
reproduce the achieved technological quality in a reliable manner.
Mechanical testing (tensile and hardness) shows that the different alloys used in Denticast project and
cast using the prototype, are in most of the results superior to those obtained with two different
commercial systems (pressure-vacuum and centrifugal systems). The samples are usable for dental
prosthesis without any risk for the patient health.
Residual Stress Analyses by Neutron Diffraction in Irradiated Double-V Butt Welded Steel Plates
Authors: Neov Dimitar , Ohms Carsten , Wimpory Robert C. , Youtsos A.G.
Published: March 2009

Neutron irradiation is known to have a considerable impact on the mechanical
characteristics and the behaviour of materials and components. The distribution of residual stresses
is one of the properties affected by irradiation. However, because of the difficulties in performing
measurements in radioactive components, not many experimental data have to date been collected.
At the High Flux Reactor (HFR) of the European Commission’s Joint Research Centre (JRC), a
facility has been developed for residual stress measurements in steel specimens subjected to longterm
irradiation. The objective of this development was to establish the neutron radiation induced
changes in the residual stresses around welds in test pieces representative of the core shroud of
boiling water reactors. Residual Stress measurements on such double-V butt welds in stainless steel
plates after irradiation exposure have been performed by neutron diffraction using this facility. The
comparison with measurements in non-irradiated companion specimens [1] showed that irradiation
changed the distribution of residual stresses. The results suggested that the impact of irradiation
varied with the distance of the test location from the specimen surface. On the basis of currently
measured data we could not draw definitive conclusion about the influence of neutron dose and
irradiation duration upon the stress modification.