bluuebunny/crossref_metadata_2025 huggingface dataset:
Principles of Microstructural Design in Two-Phase Systems
Authors: Kang Suk Joong L. , Jung Yang Il , Moon Kyoung Seok
Published: March 2009

When a polycrystal is in chemical equilibrium, the microstructure evolves as a result of grain growth under the capillary driving force arising from the interface curvature. As the growth rate of an individual grain is the product of the interface mobility and the driving force, the growth of the grain can be controlled by changing these two parameters. According to crystal growth theories, the growth of a crystal with a rough interface is governed by diffusion and its interface mobility is constant. In-contrast, the growth of a crystal with faceted interfaces is governed by the interface reaction and diffusion for driving forces below and above a critical value, respectively. As the growth rate is nonlinear for the regime of interface reaction control, the grain growth is nonstationary with annealing time. Calculations reveal that the types of nonstationary growth behavior including pseudo-normal, abnormal, and stationary are governed by the relative value of the maximum driving force, gmax, to the critical driving force for appreciable growth, gc. Recent experimental observations showing the effects of critical processing parameters on microstructural development also support the theoretical prediction. The principles of microstructural design are deduced in terms of the coupling effects of gmax and gc.
Disruption of Dislocation Cores at Grain Boundary in Nb-Doped SrTiO3 Bicrystals
Authors: Choi S.Y. , Buban J.P. , Shibata Naoya , Yamamoto Takahisa , Ikuhara Yuichi
Published: March 2009

Bicrystals of Nb-doped SrTiO3, having tilt angles of 4o~18 o with respect to [001], were
prepared by joining two single crystals at 1873 K and then investigated to identify the effect of tilt
angle on the grain boundary structure. The boundaries consisted of a regular array of dislocations but
the positioning of cores along the boundary was found to be changed from a line to a zigzag as a tilt
angle was increased up to 10o. The 14° - tilted boundary exhibited two kinds of boundary region exist
at the same grain boundary; (1) the discrete cores region as observed in 4° ~ 10° - tilted boundaries
and (2) the randomly oriented region as found in the 18° boundary. Thus it was observed that the
structure of low-angle tilt boundary changed from the discrete dislocation structure to the randomly
oriented structure as a tilt angle increases. These structural changes at the grain boundaries are
considered to be related to a minimization of strain due to the high density of dislocations.
Microstructure and Magnetic Properties of CoFeHfO Rich Nanocrystalline Thin Films Application for High Frequency
Authors: Tho L.V. , Lee K.E. , Kim Cheol Gi , Kim Chong Oh , Cho W.S.
Published: March 2009

Nanocrystalline CoFeHfO thin films have been fabricated by RF sputtering method. Co52Fe23Hf10O15 thin film is observed, exhibit good magnetic properties with magnetic coercivity (Hc) of 0.18 Oe; anisotropy fild (Hk) of 49 Oe; saturation magnetization (4лMs) of 21 kG, and electrical resistivity (ρ) of 300 01cm. The frequency response of permeability of the film is excellent. The effect of microstructure on the electrical and magnetic properties of thin film was studied using X-ray diffraction (XRD) analysis and conventional transmission electron microscopy (TEM). The results showed that excellent soft magnetic properties were associated with granular nannoscale grains of α-CoFe and α-Co(Fe) phases.
Synthesis of Magnesium Oxide Nanoparticles by Sol-Gel Process
Authors: Wahab Rizwan , Ansari S.G. , Dar M.A. , Kim Young Soon , Shin Hyung Shik
Published: March 2009

Cubic shaped Magnesium oxide nanoparticles were successfully synthesized by sol-gel method using magnesium nitrate and sodium hydroxide at room temperature. Hydrated Magnesium oxide nanoparticles were annealed in air at 300 and 500°C. X-ray diffraction patterns indicate that the obtain nanoparticles are in good crystallinity, pure magnesium oxide periclase phase with (200) orientation. Morphological investigation by FESEM reveals that the typical sizes of the grown nanoparticles are in the range of 50-70nm. Powder composition was analyzed by the FTIR spectroscopy and the results confirms that the conversion of brucite phase magnesium hydroxide in to magnesium oxide periclase phase was achieved at 300°C.The Thermo-gravimetric analysis showed the phase transition of the synthesized magnesium oxide nanoparticles occurs at 280-300°C.
High-Resolution Transmission Electron Microscopy Study of WC-Co Alloy doped with other Metal Carbides; VC, Cr3C2, and ZrC
Authors: Yamanaka Y. , Taniuchi T. , Shirase F. , Tanase T. , Ikuhara Yuichi , Yamamoto Takahisa
Published: March 2009

The WC/Co interface structures in WC-Co alloys doped with VC, Cr3C2 or ZrC were examined by high-resolution electron microscopy (HRTEM) and X-ray energy dispersive spectroscopy (EDS) with a special interest in the segregation behavior of respective dopants at the WC/Co interfaces. It was confirmed that the addition of VC or Cr3C2 were effective to reduce WC grain size while that of ZrC was not. In case of VC or Cr3C2-doped alloys, the morphology of WC grains largely changed comparing with undoped and ZrC-doped alloys. The WC/Co interfaces of the two alloys tend to form micro facets with (0001) and {1010} habits. EDS analysis with a sub-nano scale probe revealed that the dopants strongly segregated at the two habits. In contrast, such morphology change, and also dopant segregation, could not be observed in ZrC-doped alloy. In our study, doped ZrC was not found to solute in Co-phase. Doped ZrC distributed in Co-phase to form other grains mainly consisting of ZrC. The interface structures of WC/Co could be considered to be closely related to the inhibition effect to WC grain growth.
Study on the Wrinkling and Edge Irregularity during Bending of a Roll-Formed Plate
Authors: Sheu Jinn Jong , Huang Ming Yi , Liu Chin Wei
Published: March 2009

The bending tool design of a cold roll-formed blank has been discussed in this paper. The cold roll-formed blanks give a up and down bending line instead of a conventional straight line, The problems of wrinkling and edge irregularity occured frequently in such bending operation. A die design and blank pre-cutting methods are proposed in this paper to eliminate the edge irregularity. The radii of die and punch, punch profile, the gap of tools are considered as the design factors. The CAE method is adopted to obtain the measurements of the design of experiments (DOE). A fourth-order Bezier curve is proposed to desing the pre-cutting curve systemtically and automaticaly. The Golden section method is adopted to improve the pre-cutting curve design. The edge iregularity of a cold roll-formed balnk can be minimised by the proposed method. The wrinkling defects can be decreased but are not able to fuly elimiated.
The Sterilization of Dry Powdered Foods by Successive Impacts
Authors: Fujiwara Kazuhito , Hiroe Tetsuyuki , Hata Hidehiro , Furukawa Motoyasu
Published: March 2009

The thermal sterilization is limited to use for fungi and bacteria in some kinds of dry
powdered foods because of the heat sensitivity of their flavor. The sterilization method using
impulsive loads or shock waves has the characteristic to sterilize foods without heating. Higher
shock pressure can shows higher disinfecting action, but has some problems such as the degradation
of foods and the hardness of handling. The proper choice of energy sources is one of points to
make the method push to the industrial level. Safety and facility are also important factors to
develop the practical system. In this paper as the case of the lowest limit of the impact load, the
powder was impacted by mechanical hammer. It was found that the iterative impacts showed the
disinfecting effect although the efficiency was low at an impact. Several processing cycles were
required to show the significant decreasing of bacteria, because the apparent colony number (not
actual bacteria number) increased in the impact process. The numerical model to estimate the
mechanical condition in sterilizing process is also presented in this paper.
Experimental Determination of Shock Hugoniot for Water, Castor Oil, and Aqueous Solutions of Sodium Chloride, Sucrose and Gelatin
Authors: Gojani A.B. , Takayama Kazuyoshi
Published: March 2009

Shock waves are indispensable tools for medical applications, and hence their interactions with
human tissue become one of the most important basic research topics. In this paper, the
determination of shock Hugoniot curves for liquids that can model human tissue, namely water,
castor oil, and aqueous solutions of sodium chloride, sucrose and gelatin, at 10 and 20 weight
percent are presented. Underwater shock waves were generated by ignition of 10 mg silver azide
pellets and time variations of over-pressures were measured and simultaneously the shock speed
was measured by the time of flight technique. Then shock Hugoniot curves were obtained, by
assuming the Tait type equation of state, to relate the estimated density and measured pressure
values. Results show in the cases of aqueous solutions that increasing amount of additives into
water causes only a very minute decrease in the compressibility of the solution. This difference was
more pronounced in the case of sodium chloride, less for gelatin, and almost none for sucrose
aqueous solution.
A Study on the Consolidation of Cu, Ni / Graphite Powder Using Shock Compaction Method
Authors: Kim Young Kook , Hokamoto Kazuyuki , Itoh Shigeru
Published: March 2009

A shock compaction method using an underwater shockwave is used to consolidate the
Cu/graphite and Ni/graphite composites. The copper powder (particle size < 45 m) and nickel
powder (particle size < 150 m) were respectively mixed with the graphite powder (particle size <
45 m, purity 99.9%). The propagation phenomenon of underwater shock wave is studied by means
of numerical analysis (LS-DYNA 3D) in terms of the magnitude and distribution of shock pressure
impinged on the powder surface. The shock pressure of underwater shock wave obtained from
shock compaction device is approximately 16 GPa. To make a big size material (ø30mm), we
changed the inner size of powder container from ø10 mm to ø30 mm. We confirmed that the
consolidation possibility of the big size composite materials (Cu/graphite, Ni/graphite) by the shock
compaction method using underwater shock wave.
Plate Response to Buried Charge Explosion
Authors: Rolc Stanislav , Adamík Vladislav , Buchar J. , Severa L.
Published: March 2009

This paper deals with the dynamic response of clamped plate to the loading following from the detonation of buried explosive charge. The cylindrical explosive charges of 8 kg mass has been considered. The numerical analysis is carried out using the LS DYNA finite element code. Numerical results exhibit reasonable agreement with results of controlled explosion experiments. The study is oriented mainly on the effects of structure representations (solids or shells) and of computational mesh size on evaluation of the structure response.
Nano-Sized Nitrogen-Doped Ti-W Mixed Oxides: Preparation and Enhanced Photocatalytic Activities under Visible Light Irradiation
Authors: Shen Yan Fang , Xiong Tian Ying , Shang Jian Ku , Yang Ke
Published: March 2009

Nano-sized nitrogen-doped Ti-W mixed oxides (N-TiO2-x%WO3) were prepared by soft
chemical method, and their intrinsic characteristics were investigated using XRD, TEM, N2
adsorption and desorption isotherms, UV-Vis diffuse reflectance spectra and XPS. Experiments on
photodegradation of Methylene Blue (MB) under visible light irradiation were carried out to
evaluate the photocatalytic abilities of N-TiO2-x%WO3. Chemical Oxygen Demand (COD) analysis
was also performed to evaluate the mineralization abilities of N-TiO2-x%WO3. It is shown that the
N-TiO2-x%WO3 exhibited higher COD removing rates compared with Degussa P25. The color
bleaching rates of N-TiO2-x%WO3 were equal to that of Degussa P25. The enhanced photocatalytic
activities were probably related to the strong absorption abilities of the N-TiO2-x%WO3.
Oxidation Behavior and Cutting Performance between Ti0.75-Al0.25-N and Ti0.69-Al0.23-Si0.08-N Coated Tool through Measurement of Cutting Temperature
Authors: Shin Suk Hoon , Kim Chul , Ahn Dong Gyu , Kim Kwang Ho , Kang Myung Chang
Published: March 2009

Ti-Al-Si-N and Ti-Al-N coatings were deposited on WC-Co substrates by a DC magnetron
sputtering method. The oxidation behavior of two kinds of Ti0.75Al0.25N and Ti0.69Al0.23Si0.08N
coatings were comparatively investigated by XRD patterns and GDOES depth profiles. Si addition of
8 at.% into Ti-Al-N film modified its microstructure to a fine composite comprising, Ti-Al-N
crystallites and amorphous Si3N4, and to a smoother surface morphology. While the solid solution
Ti0.75Al0.25N film had superior oxidation resistance up to around 700°C, the composite Ti-Al-Si-N
film showed further enhanced oxidation resistance. Both Al2O3 and SiO2 layers played roles as a
barrier against oxygen diffusion for the quaternary Ti-Al-Si-N film, whereas only the Al2O3 oxide
layer formed at surface did a role for the Ti-Al-N film. The cutting performances of two coated
carbide ball-end mills were evaluated by cutting of AISI D2 cold-worked die steel (60 HRC) under
high-speed cutting condition. The tool wear and cutting temperature are discussed along with coating
characteristics.
Formation of TiO2 Coating Layer on the Surface Treated Ti Alloys
Authors: Ha N. R. , Yang Z. X. , Hwang Kyu Hong , Lee J. K.
Published: March 2009

Pure Titanium alloys are superiorities of biocompatibility, mechanical properties and chemical stability. The biocompatibility of Ti alloy is related to the surface effect. In this study, Ti Alloys were treated by alkali and acid activation process. And through the sol coating layer, biocompatibility were investigated. Consequently, it appeared that the porous layer was generated on the surface of alloy by surface treatment and sol coating process. It was found that with surface treatment on Ti alloy, the formation speed of porous was much quicker compared with those ones without treatment. Therefore, the biocompatibility was improved.
Manufacturing of Construction Materials from Municipal Incinerator Residue
Authors: Shin Dae Yong , Kim Kyung Nam
Published: March 2009

Municipal incinerator residue (MIR) was used as raw material to replace clay to
manufacture bricks. Brick specimens were substituted from 0 to 50 wt% MIR by 10 wt% increment
for clay. Clay-MIR brick specimens were fired at 800~1050°C for 2 h. Firing shrinkage, bulk density,
water absorption rate and compressive strength were investigated. Leaching procedure tests were also
conducted to characterize toxicity. Increasing MIR contents resulted in a decrease in water absorption
rate, firing shrinkage and increase in compressive strength of bricks. It was found that when brick
specimen with 50 wt% of MIR content was heat-treated at 1000°C for 2 h, a brick specimen could be
generated, which was compressive strength of 1256 kg/cm2, water absorption ratio of 6.8% and firing
shrinkage of 3.5%. This indicates that MIR is indeed suitable for the partial replacement of clay in
bricks
Absorption of Bentonite Compact with Absorbent Polymer
Authors: Matsushita Junichi , Yang Seong Ho , Hwang Geum Chan
Published: March 2009

The Na-bentonite compact with absorbent polymer was fabricated in order to observe their
absorption and preservation about water. Absorption of fabricated specimens in the water and
preservation of absorbed samples in the drying machine at 323 K was measured. It was obtained that
the absorption had been increasing with inhancing absorbent polymer. Absorption of As-received
Na-bentonite was lower than absorption of As-received absorbent polymer. The preservation had
been also increased with absorbent polymer was obtained. Na-bentonite compact with absorbent
polymer ware investigated the good absorption and preservation when the Na-bentonite compact with
absorbent polymer 40 mass %.
Optimization of Earth Resistance by Investigating the Surge-Wave Response
Authors: Ahn Seong Joon , Woo Jea Wook , Ahn Soo Joon , Park Chul Geun , Ahn Seung Joon
Published: March 2009

As the number of delicate semiconductor devices in the electric equipment increases, it is
also getting more important to prohibit the surge wave from intruding the equipment. The better
surge-wave protection can be achieved when we reduce the earth resistance further in the earthing
system. It is practically best, however, to set an appropriate value of earth resistance if we consider the
cost and effort required to install the earthing system. In this work, we demonstrated an example of
extracting an optimized earth resistance by using a simulator that theoretically predicts the evolution
of discharge current of the earthing system. The measure discharge currents of the real earthing
system with the optimum earth resistance has confirmed that our method was efficient and useful.
Development of Inorganic Binder with MSWI Ash
Authors: Lee Woo Keun , Park Eun Zoo , Kim Young Do , Son Se Gu , Lee Ji Hyeon
Published: March 2009

Municipal Solid Waste Incinerator (below MSWI) ash is used to develop inorganic binder for preparing geopolymer concrete in this study. Toxic substituents, such as heavy metals are de-toxificated by above-mentioned new solidity technique. Slag and coal fly ash are used as active filler to enhance compressive strength. MSWI ash was mixed with slag and coal fly ash to make geopolymer concrete. They were solidified under alkali condition and dried at 50°C and 80°C, respectively. Compressive strength was measured to evaluate the characteristics of specimens for the period of 3, 7 and 14 days. Compressive strength measurements show a maximum strength of almost 13.7 MPa after 14 days. The mineral phases of specimen were analyzed by XRD. And the morphology was analyzed by the photo of SEM. The micro-structure of inorganic binder prepared was analyzed by FTIR. Korea Standard leaching Test (KSLT) and TCLP method are used to the environmental safety of inorganic binder. Raw FA measured concentrations of Cu and Pb were 0.30 ppm and 28.31 ppm, respectively. Leaching amounts of heavy metal were noticeably reduced after the solidification of MSWI as with active filler. It is possible to de-toxificate MSWI ash by new solidity techniques. And it may be used as alternative concrete.
Physicochemical Characteristics of ZnS Immobilized on Spherical Activated Carbon for Removing HA(Humic Acid)
Authors: Lee Joon Jae , Suh Jeong Kwon , Hong Ji Sook , Lee Jung Min , Park Jin Won
Published: March 2009

In this study, spherical activated carbons contained ZnS(Zn-SPAC) were successfully
prepared through carbonization/activation processes. Strong acid ion exchange resin as starting
material of Zn-SPAC was treated by 0.01 N zinc solution. Ion exchange treatment was performed
from one time to three times for controling zinc content. The ion exchanged resins was activated
under N2/H2O-vapor atmosphere at 900 °C for 0.5 hr following by carbonization treatment at 700 °C
under N2 atmosphere. The Zn-SPAC samples were measured physicochemical characteristics such as
X-ray patterns, SEM image, energy dispersive X-ray spectra, BET specific surface area, intensity and
zinc content and used to remove humic acid(HA) in batch reactor for measuring photochemical
activity. The X-ray patterns were appeared ZnS type. The Zn-SPAC had large BET specific surface
area and their shape was spherical with a diameter about 350 ~ 400 μm. When the Zn-SPAC were
dosed in UV reactor, the HA removal efficiency increased upto 60 % at 4hr. The order hand, the HA
removal efficiency by only UV-C(λmax =254nm) irradiation was not good about 15 %. Therefore,
we infer that the Zn-SPAC have good photochemical activity and presented possibility of
photocatalyst for water purification.
Investigation of Mechanical Property and Thermal Shock Behavior of Machinable B4C/BN Ceramics Composites
Authors: Jiang Tao , Jin Hai Yun , Jin Zhi Hao , Yang Jian Feng , Qiao Guan Jun
Published: March 2009

The machinable B4C/BN ceramics composites were fabricated by hot-pressing sintering process at 1850oC for 1h under the pressure of 30MPa. The mechanical property, thermal shock behavior and machinability of the B4C/BN ceramics composites were investigated in this article. The experimental results showed that the fracture strength and fracture toughness of the B4C/BN nanocomposites were significantly improved in comparison with the B4C/BN microcomposites. The Vickers hardness of the B4C/BN nanocomposites and B4C/BN microcomposites decreased gradually with the increasing content of h-BN, while the machinability of the B4C/BN nanocomposites and B4C/BN microcomposites were significantly improved. The B4C/BN ceramics composites with the h-BN content more than 20wt% exhibited excellent machinability. The thermal shock resistances of the B4C/BN ceramics composites were better than that of the B4C monolith, and the thermal shock resistance of the B4C/BN nanocomposites was much better than that of the B4C/BN microcomposites. The thermal shock temperature difference (-Tc) of B4C monolith was about 300oC, while the -Tc of the B4C/BN microcomposites was about 500oC, the -Tc of the B4C/BN nanocomposites was about 600oC.
Copolymerization of Alkoxysilanes: An Interesting Route to Core-Shell Silica-Silicone Nanoparticles
Authors: Lopes Dias Marcos , Santos Marlon S. , Alves Felipe Rodrigues , Azuma Chiaki
Published: March 2009

Copolymerization of silicon alkoxides in alcoholic basic medium using trialkyl- or triarylchlorosilanes as terminator was investigated. Tetraethoxysilane (TEOS), phenyltriethoxysilane (PTEOS) and vinyltriethoxysilane (VTEOS) were used as monomers and triphenylchlorosilane (TPCS) and trimethylchlorosilane (TMCS) as terminator. The copolymerization of TEOS with PTEOS and VTEOS produces core-shell silica-silicone nanospherical hybrids containing large amounts of functional groups in the structure of their external layer. The structure is the result of the fast hopolymerization of TEOS in a first stage of the reaction, forming the core, followed by copolymerization of TEOS and the alkyl- or vinyl-trialkoxysilane comonomer in its last stage. The structure was confirmed by Raman and FTIR spectroscopy, wide angle X-ray scattering (WAXS) and thermogravimetry. The control of particle size is effectively made by the termination reaction and particles with average diameter between 20 and 100 nm were obtained. Introduction of other chemical functions on the surface of these nanoparticles can be carried out by common reactions with the functional surface groups. As an example, sulfonation of particles containing phenyl groups on the surface by direct sulfuric acid and chlorosulfonic acid was investigated and the results discussed.
Synthesis, Hydrogenation and Mechanical Milling of Pseudo-Binary Zr(NbxV1-x)2 (0≤x≤0.65) Alloys
Authors: Loureiro S.A. , Fruchart Daniel , Rivoirard Sophie , dos Santos Dílson S. , Tavares L.M.
Published: March 2009

AB2 metallic alloys provide large quantities of Laves phases when prepared using
conventional thermal routes. In the present work the crystallography, hydrogenation behavior and
mechanical milling (MM) effects of the pseudo-binary Zr(NbxV1-x)2 (0<x≤0.65) system are studied.
It is found that the partial replacement of V by Nb atoms leads to the formation of cubic C15
(0<x≤0.20) and hexagonal C14 (0.35≤x≤0.65) Laves phases. For x≤0.20, the niobium additions
promote a slight increase of the hydrogen storage capacity by the C15 phases. For 0.35≤x≤0.65, the
reduction of the molar fraction of the C14 phase promotes an increase of the alloy hydrogen storage
capability. Iron incorporation plays a major role on the type of final mechanically-milled Zr-Nb-V
alloys obtained: a transformation from Laves phases (C14 and C15) to an fcc (Fm3m) one; while, in
the absence of Fe, amorphization of the system was observed, as predicted by Miedema Model. As
a general result, the mechanical milling of the Zr-Nb-V alloys results in a reduction of the hydrogen
storage capacity, at least for long processing times.
Measurement of Internal Strain in Materials Using High Energy White X-Ray at SPring-8
Authors: Shibano Junichi , Shobu Takahisa , Suzuki Kenji , Kiriyama Koji , Kajiwara Kentaro , Kaneko Hiroshi , Kobayashi Michiaki
Published: March 2009

This paper presents a basic research on a measurement of strain in the bulk of materials
by using high energy white X-ray from a synchrotron radiation source of SPring-8 in Japan. A
high-tensile strength steel (JIS-SHY685) was used as a specimen loaded with bending. Strain
distribution in it was evaluated by the energy dispersive method using diffracted X-ray transmitted
through the specimen. As a result, the internal strain of high-tensile steel of 5, 10 and 15 mm
thickness could be evaluated using white X-ray which range of energy from 50 keV to 150 keV.
The measurement with a high degree of accuracy was accomplished using α-Fe321 diffraction in
this material. The results showed that the internal strain measurement in the depth of the order of
millimeter using the high energy white X-ray is practicable at SPring-8.
Residual stresses in Al2O3/Y-TZP Ceramic Laminates Fabricated by Tape and Slip Casting
Authors: Ruiz-Hervias Jesus , Bruno Giovanni , Gurauskis Jonas , Sanchez-Herencia A.J. , Baudin C.
Published: March 2009

Residual stress profiles were measured by neutron diffraction in Al2O3/Y-TZP ceramic
composites containing 5 and 40 vol.% Y-TZP fabricated by conventional slip casting and by a novel
tape casting route. Residual stresses in the zirconia are tensile and increase as its volume fraction
decreases. For the alumina matrix, residual stress is compressive and increases with the zirconia
volume fraction. In the composite with 5 vol.% zirconia, the processing route does not have an
influence on residual stresses. However, in the composite with 40 vol.% zirconia, residual stresses
are different in the samples obtained by both processing routes.
Residual Stresses and Void Kinetics in AlSiC MMCs during Thermal Cycling
Authors: Schöbel Michael , Requena Guillermo C. , Kaminski Heinz , Degischer Hans Peter , Buslaps Thomas , Di Michiel Marco
Published: March 2009

AlSi7Mg/SiC/70p (AlSiC) is used for heat sinks because of its good thermal conductivity
combined with a low coefficient of thermal expansion (CTE). These properties are important for
power electronic devices where heat sinks have to provide efficient heat transfer to a cooling
device. A low CTE is essential for a good surface bonding of the heat sink material to the insulating
ceramics. Otherwise mismatch in thermal expansion would lead to damage of the bonding
degrading the thermal contact within the electronic package. Therefore AlSiC replaces increasingly
copper heat sinks. The CTE mismatch between insulation and a conventional metallic heat sink is
transferred into the MMC heat sink. The stability of the interface bonding within a MMC is critical
for its thermal properties.
In situ thermal cycling measurements of an AlSi7Mg/SiC/70p MMC are reported yielding the
void volume fraction and internal stresses between the matrix and the reinforcements in function of
temperature. The changes in void volume fractions are determined simultaneously by synchrotron
tomography and residual stresses by synchrotron diffraction at ESRF-ID-15. The measurements
show a relationship between thermal expansion, residual stresses and void formation in the MMC.
The results obtained from the in situ measurements reveal a thermoelastic range up to 200 °C
followed by plastic matrix deformation reducing the volume of voids during heating. A reverse
process takes place during cooling. Thus the CTE becomes smaller than according to thermoelastic
calculations. Damage could be observed after multiple heating cycles, which increase the volume
fraction and the size of the voids.
The consequence is local
debonding of the matrix from the
reinforcement particles, which
leads to an irreversible reduction
of the thermal conductivity after
multiple heating cycles.
Residual Stress in α-Brass during Annealing
Authors: Wawszczak Roman , Baczmanski Andrzej , Wierzbanowski Krzysztof , Wroński Sebastian , Braham Chedly , Seiler Wilfrid
Published: March 2009

The evolution of residual stress and crystallographic texture during thermal treatment
was studied using X-ray diffraction. Polycrystalline α-brass samples were examined after cold
rolling and afterwards after annealing at different temperatures in the range of 50 0C - 450 0C.
Additionally, the width of the diffraction peak was measured in order to estimate the variation of
the dislocation density. The interpretation of experimental data was based on a fitting procedure for
which the anisotropic diffraction elastic constants calculated by a self-consistent approach were
used. As the result of analysis, the values of the first order and second order stresses were
determined in each sample.
Influence of Ceramic Aggregate on the Microstructure of Filtration Materials
Authors: Ma Xiao E , Guo Hui , Li You Guo
Published: March 2009

In this paper, by some technological process, the reusable filtration materials has been
made by using the main waste residue of ceramic industry—waste ceramics as the aggregate and
mixing with proper binder and pore-forming agent. The production process of filtration materials
and the character of light CaCO3 as pore-forming agent were described; For the selected raw
materials, changed the ratio and aggregate granularity, the influence of ceramic aggregate content
on the aperture, aperture distribution, porosity and bending strength of filtration materials and the
influence of aperture distribution of aggregate on sample’s capability have been revealed based on
the XRD analysis, SEM observation and bending strength measurement of filtration materials; at
the same time, the influence of sintering temperature on the porosity and bending strength of
filtration materials was also studied. The results show that the better filtration effect and better
chemical durability, the higher bending strength (15MPa) of the synthetical filtration materials can
be obtained when the content of aggregate, the particle size and the sintering temperature are
respectively 50~55wt%, 150~1804m and 1205°C.
Effect of Molybdenum on Hot Deformation and Processing Maps of Austenitic Stainless Steels
Authors: Wang Ming Jia , Long Shan Shan , Mu Song Mei , Wang Yan , Chen Lei
Published: March 2009

In this paper, hot compression tests were carried out using a Gleeble-3500 simulator to establish
the law of hot deformation and recrystallization behavior, and to generate the corresponding
processing maps. The influence of Mo was also investigated by comparing the results of hot
deformation in such steel. The addition of molybdenum to stainless steel slightly increases the hot
deformation stress and recrystallization temperature, while reduces the efficiency of power
dissipation η.
Application of Time-Ageing Time and Time-Temperature-Stress Equivalence to Nonlinear Creep of Polymeric Materials
Authors: Zhao Rong Guo , Luo Wen Bo , Li Qi Fu , Chen Chao Zhong
Published: March 2009

Based on the observations that high temperature accelerates creep rate of polymer while
physical ageing plays a reverse role, and that there is an analogy between the influences of stress
and temperature on the intrinsic times of polymers, the time-ageing time superposition principle
(TASP) and the time-temperature-stress superposition principle (TTSSP) are used to evaluate the
long-term creep behavior of poly(methyl methacrylate) (PMMA). PMMA specimens were aged for
2 to 120 hours at identical temperature, their short-term creep strains with 2-hour test duration were
measured under various stress levels ranging from 14 to 30 MPa at room temperature, and modeled
by means of time-ageing time equivalence and time-stress equivalence. The results show that the
creep rate increases with stress, but decreases with ageing time. The ageing time shift factors vary
with the stresses at which the shifts are applied. The ageing shift rate is independent on imposed
stress in linear viscoelastic region, while it decreases with increasing stress when the material
behaves in a nonlinear viscoelastic manner. The master creep compliance curve up to about
1-month at reference ageing time 120 hours and stress 18 MPa, which is nearly 2.5 decades longer
than the test duration, is constructed by shifting the creep curves horizontally along the logarithmic
time axis. The result illustrates that TTSSP, combined with TASP, provides an effective accelerated
test technique for long-term mechanical behaviors of polymers.
Analyses of the Influencing Factors of Rotating Impeller Degassing Process and Water Simulation Experiment
Authors: Mi Guo Fa , Liu Xiang Yu , Wang Kuang Fei , Qi Shou Ping , Wang Hong Wei , Niu Ji Tai
Published: March 2009

On the basis of similarity principle a water-simulative study of the process of rotating
impeller degassing (RID) was executed by means of self-made purifying system. The influencing
factors on the RID process were studied and laid a theoretical basis for the further development of
this kind of technique. The shape of vortex originated in rotating of impeller and its adverse effect
on degassing effectiveness were discussed. Meanwhile the influences of shape as well as position of
bluff body on degassing efficiency were investigated. The impacts of parameters such as gas feed
rate and rotational speed of on degassing efficiency were discussed. The result revealed that the
structure and design parameters of impeller are the decisive factors of effectiveness of RID facilities,
and the design of the swivel head ought to aim for increasing the additional turbulent shear stress on
air bubble and improving the degassing condition.
Researches on Rules of the Longitudinal Residual Stress Distribution in Straightening Deformation Zone of Heavy Rail with Multi-Rollers
Authors: Chen Lin , Tian Zhong Liang , Gao Mi Chao , Zong Wei , Wang Jian Guo , Yang Wen Qing , Wang Ping Yi , Wu Zhang Zhong , Duan Yong Qiang , Wang Yong Ming
Published: March 2009

The paper simulated and researched the straightening process of heavy rail by finite
element software of ANSYS/LS-DYNA. The residual stress of the rail head, rail base, rail loin in the
7th deformation zone meets the real straightening condition in the straightening simulation. The
calculation indicates: The residual stress of the rail head, rail base, rail loin in various deformation
zones varies significantly like the variation of tensile-compression-tensile. Compared with the on-site
rule, the residual stress of rail base decreased155 Mpa, this is in agreement with the values of practice.
Heat-Stress Fields Numerical Simulation of Aluminum Profile Extrusion by Porthole Die
Authors: Jian Zhang , Li Yun Tao , Chu Liang , Bi Da Sen , Cui Hong Xiang
Published: March 2009

A solid geometry model of porthole die is built up by CAD . Pointing to some problems
in the extruding process, such as the die fraying and the low quality of the welding during the
extruding process, and the interrelated parameters, the main forming process of 7005 aluminum
alloy gear pump by porthole die is simulated by using numerical analysis software DEFORM-3D
with regard to heat-stress fields. Based on the results of numerical simulation, this paper gives some
improvements and suggestions for optimizing the forming process.
Modeling Stress Strain Curves for Nonlinear Analysis
Authors: Gao Hu Sheng
Published: March 2009

Methods of modeling stress strain curves for nonlinear stress analysis are discussed in
order to obtain comparable results between different finite element analysts and between different
versions of designs. The most common method for modeling stress strain curves is to use Ramberg-
Osgood equation. For materials with significant discontinuous yielding, Ramburg-Osgood
approximation leads to some problems near discontinuous yielding point. Discontinuous yielding
occurs when sudden onset of plastic deformation associated Luders band takes place in a uniform
test sample. For engineering structures and machine components, the propagation of Luders band
may not occur in deformation process because of non-uniform stress distribution caused by stress
concentration, complicated loading condition etc. A modified Ramberg-Osgood method for
modeling stress strain curve is proposed.
The Electrical Contact Resistance in Resistance Welding Evaluated by Gleeble Testing Machine
Authors: Zhou Wei Min
Published: March 2009

Electrical contact resistance is an important parameter in resistance welding. In this
article, a Gleeble 3500 thermal-mechanical testing machine was employed to measure the contact
resistance. The machine is equipped with a special electrical resistance measuring system. The
contact resistance is experimentally investigated for welding low carbon steel to themselves. A
detailed work was carried out to investigate the influence of pressure, temperature on the contact
resistance of low carbon steel. The experimental results show that the contact resistance decreases
when pressure or temperature increases.
Modified Tartagli Method for Calculation of Jominy Hardenability Curve
Authors: Sitek Wojciech , Trzaska Jacek , Dobrzański Leszek Adam
Published: March 2009

Basing on the experimental results of the hardenability investigations, which employed
Jominy method, the model of the neural networks was developed and fully verified experimentally.
The model makes it possible to obtain Jominy hardenability curves basing on the steel chemical
composition. The modified hardenability curves calculation method is presented in the paper,
initially developed by Tartaglia, Eldis, and Geissler, later extended by T. Inoue. The method makes
use of the similarity of the Jominy curve to the hyperbolic secant function. The empirical formulae
proposed by the authors make calculation of the hardenability curve possible basing on the chemical
composition of the steel. However, regression coefficients characteristic for the particular steel
grade must be known. Replacing some formulae by the neural network models is proposed in the
paper.
Microstructures and Toughness in Simulated Coarse Grain Heat-Affected Zones of Copper-Bearing Steel
Authors: Liu Wen Yan , Wang Lai , Liu Ji Bin , Li Ping He , Miao Kai , Han Rong Dong
Published: March 2009

Microstructures and toughness of simulated coarse grain heat-affected zone of hot
continuously rolled copper-bearing steel were investigated using physical simulation. The results
showed that brittlement is easy to happen in the region of CGHAZ with slower thermal cycles
(t8/5≥45s). Granular bainite transformed from austenite led to brittlement. The dimensions of
granular martensite and austenite (M-A) constituents are main factors influencing the impact
toughness. There is no visible effect on the toughness when the dimensions of M-A constituents are
less than 1μ m. However, the toughness decreases greatly once the dimensions exceed 1μ m.
Therefore, decreasing the dimensions of M-A constituents by controlling weld heat input will do
good to improve the impact toughness of copper-bearing steel.
Recent Developments of Severe Plastic Deformation Techniques for Processing Bulk Nanostructured Materials
Authors: Valiev Ruslan
Published: March 2009

Since the mid-1990’s the fabrication of bulk nanostructured metals and alloys using
severe plastic deformation (SPD) has been evolving as a rapidly advancing direction of modern
nano-materials science that is aimed at developing materials with new mechanical and functional
properties for advanced applications. This paper highlights and considers two new trends in SPD
processing, which are recently being developed for fabrication of bulk nanostructured materials
(BNM). One of these recent developments is associated with nanostructuring of metals and alloys
by SPD processing for advanced properties. The new strategies and approaches to produce
nanometals with enhanced and often unique properties are discussed. Another new direction is the
progress in the processing of BNM not only at laboratory scale but also at the level semi-products
(sheets, wires, rods, etc.) suitable for production implementation. The paper considers these
developments together with the examples performed at our laboratory in Ufa (Russia), which lay a
firm foundation for the BNM use in advanced structural and functional applications.
Ultrafine and Nanostructured Refractory Metals Processed by SPD: Microstructure and Mechanical Properties
Authors: Wei Q. , Ramesh K.T. , Kecskes Laszlo J. , Mathaudhu Suveen N. , Hartwig K.T.
Published: March 2009

Severe plastic deformation (SPD) has been demonstrated to be the most efficient
method to produce bulk metals with ultrafine grained (UFG, 100 nm < grain size d < 500 nm) and
nanocrystalline (NC, d<100 nm) microstructures. Such metals exhibit some unique properties
owing to their unusual microstructures such as high-energy, non-equilibrium grain boundaries.
Efforts in the past two decades have focused on metals with face-centered cubic (fcc) structures.
Recent experimental results have shown that UFG/NC metals with body-centered cubic (bcc)
structures have some properties that are distinct from their fcc counterparts. Further, the majority of
the fcc metals are very ductile and have relatively low melting points, making them easier to
process using SPD. On the contrary, many bcc metals are refractory, and are very sensitive to
interstitial impurities, rendering them difficult to work via SPD. In this article, we attempt to
summarize the state-of-the-art of UFG/NC refractory metals processed by SPD, with focus on the
microstructure and mechanical properties. Comparisons with UFG/NC fcc metals are made where
appropriate. Outstanding issues and future directions are also addressed.
The Study of Field Application of Digital Radiography Testing for Power Plant Weldments
Authors: Park Sang Ki , Gil Doo Song , Ahn Yeon Shik , Cho Yong Sang
Published: March 2009

Since Power Plant has tens of thousands welded parts in its structures, the quality on
the welded parts are always a key factor for ensuring the reliability of the structures. Film based
Radiography Test (hereinafter called “FRT”) is a generally accepted solution in inspecting the
welded structure. However, the RT demands complex workflow, high cost, hazardous waste
disposal, and etc…. In an effort to get over such shortcomings from FRT and present alternative
inspection tools, this study was intended to evaluate a Digital Radiography Test (hereinafter called
“DRT”). In this study, the evaluation were focused on if a DRT is applicable to the inspection of
Welded structure in Power Plants, and what benefits can be generated in a use of DRT.
Micromechanical Responses of Sn-3.5Ag-xCo Lead-Free Solders by Nanoindentation
Authors: Gao Feng , Nishikawa Hiroshi , Takemoto Tadashi
Published: March 2009

The lead-free casting solders Sn-3.5Ag-xCo (x = 0, 0.1, 0.5 and 1.0 mass%, respectively)
were subjected to isothermal aging at 150°C for 0, 1008 and 2016 h, respectively. The
nanoindentation methodology was employed herein to assess the mechanical properties. In
particular, the strain rate sensitivity index value was derived from the creep deformation at the
dwell time of the target constant load using Mayo-Nix theory. Basically, there is no remarkable
tendency of the variation of Young’s modulus after aging, while to some extent, the hardness of the
alloys drops. The strain rate sensitivity index value continues to decrease with the prolonged aging
time. The solder grain growth and the coarsening of the intermetallics namely, Ag3Sn and CoSn2,
are responsible for the mechanical evolution of the alloys. The 1.0% (mass%) Co additive improved
the hardness of the solder alloy, and caused the decrease of the strain rate sensitivity value.
Residual Stresses of Friction Stir Welded 2024-T4 Joints
Authors: Li Ting , Shi Qing Yu , Li Hong Ke , Wang Wei , Cai Zhi Peng
Published: March 2009

Friction stir welding (FSW) is a solid-state joining technique which can produce
high-quality joints efficiently. The residual stresses in FSW are generated due to the effect of both the
uneven temperature field and of the tool force, which is different from that in fusion welding. In this
study the residual stresses of 3mm-thick 2024-T4 aluminum alloy FSW joints have been investigated
by using the Hole-drilling method. To reduce the influence of drilling upon the experimental results,
annealed stress-free 2024 aluminum alloy plates were drilled; the relieved strains were measured and
were subtracted from the total strains measured from the joints. The results showed that the
longitudinal residual stresses in the joint were much larger than the transverse residual stresses; high
longitudinal tensile residual stresses were concentrated near the tool shoulder direct affected zone and
asymmetrically distributed at the different sides of the weld line; i-e, high at the advancing side and
relatively low at the retreating side. Outside the tool shoulder direct affected zone, the longitudinal
residual stresses decreased rapidly and became compressive residual stresses away from the weld line;
the peak of the longitudinal residual stresses was 164.5MPa.The mechanism of the generation of the
residual stresses was analyzed preliminarily.
Numerical Analysis of Arc Plasma with Metal Transfer in GMAW
Authors: Hirata Yoshinori , Ohnishi K.
Published: March 2009

A numerical model of time-dependent gas shielded metal arc is described, which was
developed in order to make clear the kinetics of arc plasma together with metal transfer. It is
possible to calculate and visualize time-dependent temperature and fluid flow field of argon
shielded metal arc plasma with the grow-up and the subsequent detachment of the liquid metal drop
at the wire tip. Numerical calculation shows that the arc shape in globular transfer abruptly changes
at the moment of metal drop detachment. Whereas, the spray transfer arc seems to be stable and
almost does not fluctuate with metal transfer.
Optimization of Electric Resistance Welding Conditions in Small Diameter X60 Pipes for HIC Resistance
Authors: Hong H.U. , Lee Jong B.
Published: March 2009

The optimization of electric resistance welding conditions has been investigated in
order to improve the resistance to hydrogen induced cracking at bondline in API 5L X60 line pipes
from center-slit coils. It was found that the elongated (Si, Mn, Al) rich oxide inclusions at bondline
provided a preferential site for HIC, but no evidence on the center segregation effects was found.
Design of experimental (DOE) method was used to find out the optimum ERW condition in the
viewpoint of the minimization of defects ratio at bondline. The optimum ERW condition suggested
by DOE successfully led to an excellent HIC resistance at bondline. Furthermore, it was observed
that there was no relation between segregation and HIC resistance at bondline.
Friction Stir Lap Joining of AC4C Cast Aluminum Alloy and Zinc-Coated Steel
Authors: Chen Y.C. , Komazaki T. , Kim Y.G. , Tsumura Takuya , Nakata Kazuhiro
Published: March 2009

AC4C cast aluminum alloy and zinc-coated steel were friction stir lap welded, and the
microstructures and mechanical properties of the joints were examined and analyzed. Experimental
results show that the welding speeds have a significant effect on the tensile properties and fracture
locations of the joints at a rotational speed of 1500 rpm. When the welding speed is higher than 60
mm/min, the joints fracture in the zinc-coated steel base material and the tensile strength is equal to
that of the zinc-coated steel; when the welding speed is lower than 60 mm/min, the joints fracture in
the interface and the shear strength is about 50 MPa. The change of the fracture locations is
attributed to the presence of large quantity intermetallic compounds adjacent to the interface of the
joints. The composition and formation mechanism of the intermetallic compounds and its effect on
the mechanical properties of the joints were discussed.