bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and Thermal Property of Phase Change Material Microcapsules by Phase Separation
Authors: Zhang Yan , Lin Wei Jie , Yang Rui , Zhang Yin Ping , Zhang Qing Wu
Published: March 2009

Compared to conventional single-phase fluids, the latent functionally thermal fluid (LFTF),
with phase change particles of μm magnitude in size dispersed in it, shows much greater apparent
specific heat and heat transfer rate between the fluid and the duct wall. Therefore, for given heat
transportation quantity, the mass flow rate and the pump consumption can be reduced greatly. Due to
these, LFTF is a promising material in the fields of heat exchanging. In this paper, phase change
material (n-tetradecane) was encapsulated by polymethyl mathacrylate (PMMA), polystyrene (PS)
and blend of them by internal phase separation method to form microcapsule of 1~2μm in size. The
chemical structures were demonstrated by using Fourier transform infrared spectroscopy (FTIR). The
core-shell structure was observed using phase contrast microscope. Differential scanning calometry
(DSC) results indicated that the phase change enthalpy of the containing 75wt% n-tetradecane as core
material reaches 150.7 J/g.
Mechanical Properties of Cu-4.0wt%Ni-0.95wt%Si Alloys with and without P and Cr Addition
Authors: Watanabe Chihiro , Nishijima Fumiya , Monzen Ryoichi , Tazaki Kazue
Published: March 2009

The effects of P and Cr addition and two-step aging on the microstructure and mechanical
properties of a Cu-4wt%Ni-0.95wt%Si alloy have been examined. The addition of 0.02wt%P
improves both strength and elongation because it suppresses discontinuous precipitation reaction. The
Cr addition to the Cu-Ni-Si-P alloy decreases greatly the grain size, resulting in an increase in
elongation. Two-step aging, pre-aging at 300 or 350oC and subsequent second-step aging at 450oC,
causes an increase in strength without reducing elongation. The increase in strength is attributable to
the decrease in inter-precipitate spacing by the two-step aging. The two-step aged Cu-4wt%Ni-
0.95wt%Si-0.02wt%P-0.02wt%Cr alloy attains a tensile strength of 830MPa, an elongation of 13%
and an electrical conductivity of 35%IACS.
Phase Diagram and Precipitation Behaviour in Ni-Rich Region of Ni-Ta-Al Ternary System
Authors: Tsukada Yuhki , Hasuike Koichi , Murata Yoshinori , Morinaga Masahiko
Published: March 2009

Tantalum (Ta) addition is one of the promising method for increasing the strength of
Ni-based wrought alloys such as Inconel 718, because Ta is an element having a high melting
temperature. For wrought alloys, it is necessary to make clear the phase relationships at
700~1000°C, but there is a few report on phase diagrams of Ni-Ta and Ni-Ta-Al systems at those
temperatures. In this study, the phase diagram in Ni-rich region of Ni-Ta-Al system at 800°C, which
is the important temperature for the practical use of the wrought alloys, was investigated. The
equilibrium relations of each phase were examined by a conventional XRD, SEM/EDX and TEM
observations. It was found that the γ-phase region expanded considerably towards Ta-rich
compositional region in Ni-Ta-Al system at 800°C. Also, it was observed that the γ phase
precipitated secondarily in the primary precipitated γ’ phase in Ni-10.5mol%Ta-5.5mol%Al alloy.
Ni8Ta phase was not detected even in Ni-Ta binary system in this study, although this phase was
reported previously.
Relation between Diffuse Scatterings and Fermi Surface Nesting in Iron Doped Ti-Ni Alloys
Authors: Yamamoto Takuya , Choi Mi Seon , Majima Sho , Fukuda Takashi , Kakeshita Tomoyuki , Taguchi Eiji , Mori Hirotaro
Published: March 2009

We have studied diffuse scatterings appearing in Ti-(50-x)Ni-xFe (x = 6, 7, 8, 10) alloy,
which shows negative temperature coefficient in electrical resistivity below a temperature Tmin.
Electron diffraction pattern of each alloy exhibits diffuse scatterings below Tmin on cooling. The
intensity maximum of the diffuse scatterings is located at an incommensurate position of g+<ζζ0>,
where g represents reciprocal lattice points of the B2-phase. The value ζ is slightly smaller than 1/3
and decreases with increasing Fe content. The diffuse scatterings of the present alloys are well
explained by the nesting effect of the Fermi surface in the B2-type structure, i.e., ζ of each alloy
agrees with the length of nesting vector in the [110] direction, which is evaluated by a first-principle
calculation.
The Effect of Ag-Addition on Precipitation Sequence in Al-1.0mass%Mg2Si-Excess 0.4mass%Si Alloy
Authors: Niwa Kenji , Matsuda Kenji , Nakamura Junya , Sato Tatsuo , Ikeno Susumu
Published: March 2009

It is well known that Ag additional Al-1.0mass%Mg2Si-excess0.4mass%Si alloy (ex.
Si-Ag alloy) has higher hardness and elongation than those of Al-1.0mass%Mg2Si-excess
0.4mass%Si alloy (ex. Si alloy). However, precipitation sequence of ex. Si-Ag alloy is not clear yet.
In this work, precipitation sequence of ex. Si-Ag alloy has been investigated using high resolution
transmission electron microscopy and X-ray energy dispersive spectroscopy. Precipitates were
classified into several kinds by HRTEM images and SAED patterns, and relative frequencies of
precipitates were also investigated. Its precipitation sequence was compared with that of ex. Si alloy.
Type-A, Type-B and Type-C precipitates as special metastable phase in excess Si type Al-Mg-Si
alloy, has been observed in ex. Si-Ag alloy, but β’ phase increased and Type-A and Type-B
precipitate decreased in this study. Type-A precipitate was found at only grain boundary.
Atomic Force Microscopy of Sintered and Thermoplastic Polyimide Surfaces after Macroscopic Wear Tests
Authors: Samyn Pieter , Quintelier Jan , Schoukens Gustaaf , de Baets Patrick , De Waele Wim
Published: March 2009

Polyimide surfaces after macroscopic wear at 80 to 260°C are studied by atomic force
microscopy to give additional insight in the tribophysical and -chemical processes during sliding.
Three sliding regimes are distinguished with hydrolysis resulting in rough surfaces, imidisation
resulting in orientation of polymer molecules and melting resulting in short-range arrangements.
Fatigue Fracture Behavior of Mg-Zn-Y Alloys
Authors: Tsushida Masayuki , Toda Kazuaki , Kitahara Hiromoto , Ando Shinji , Tonda Hideki
Published: March 2009

Recently, Mg-Zn-Y alloys with superior performance, which have a long period stacking
order (LPSO) phase, have been developed. Therefore, it is important to understand fundamental
fatigue properties in such materials. In this study, the fatigue fracture behavior of the Mg96Zn2Y2
alloy has been investigated with a plain bending testing machine, which was originally developed
for thin sheet specimen at room temperature and 523K. One end of the sheet specimen is fixed at a
voice coil of the loudspeaker and the other end is set free. A bending mode resonance occurs in the
specimen due to forced vibration at the fixed end. To estimate stress amplitude of bending,
deflections at the free end of the specimen oscillating at a frequency of about 200~500Hz was
measured by a laser displacement gauge. For comparison, AZ31B alloy also has been investigated.
S-N curve for the Mg96Zn2Y2 alloy was obtained using a stress ratio of R=-1, and the fatigue
strengths were estimated as 200MPa at room temperature and 120MPa at 523K at 106~107 cycles.
These values correspond to about 50% of 0.2% proof strengths of the Mg96Zn2Y2 alloy. Two types
of fatigue surface were observed in the Mg96Zn2Y2 alloy. One was striation-like-pattern and the
other was relatively flat surface. Striation-like-pattern was similar to fatigue surface of AZ31B.
Therefore, these two types of fatigue surface correspond to crack passing through α-Mg phase and
LPSO phase, respectively. The feature of fracture surface at 523K was almost the same as that at
room temperature.
Developments of Magnesium Alloys by Melt Stirring Method
Authors: Ando Shinji , Bu Le Ping , Tanaka Shunsuke , Kitahara Hiromoto , Tonda Hideki
Published: March 2009

For development of high strength magnesium alloys, a melt stirring method was employed
to Mg-Al and Mg-RE (rare earth metal) alloys. As reinforcement particle, B2O3 powder was added
into melts and stirred at 953K in 10 or 20 minutes with argon atmosphere. The grain sizes of both
alloys were decreased by 3wt% B2O3 addition. These results show that B2O3 have grain refinement
effects to magnesium alloys. Micro Vickers hardness of Mg-Al alloy was increased by 3wt% B2O3
addition. On the other hand, the hardness of Mg-RE alloy was decreased by B2O3. Though addition
of B2O3 into Mg-Al and Mg-RE systems make grain size to fine, the hardness of Mg-RE alloys
decreased. The tensile properties of Mg-RE alloys with B2O3 were extremely improved by extrusion
process.
On-Line Aging to Improve the Tensile Strength and Conductivity of Cold-Drawing AA6201 Wires
Authors: Zhou Tian Guo , Jiang Zheng Yi , Wen Jing Lin , Tieu A. Kiet
Published: March 2009

AA6201 with main compositions of Mg-0.5 wt % and Si-0.5 wt %, is a typical electric
conductive alloy which shows remarkable combination of high strength and high electric conductivity
after heat treatment. Cold working and aging treatment process have a significant effect on its
mechanical properties and conductivity. Shearing/Cooling Rolling process (SCR) was proposed to
produce the feedstock for all aluminum alloy conductor. The effects of cold drawing on the properties
of the alloy produced by SCR process were investigated. There are two methods used in the study, one
is the cold drawing and aging heat treatment (CDAH) to produce the wires, the feedstock prepared by
SCR and on-line solution, the other is the feedstock prepared by SCR and on-line solution-aging heat
treatment plus cold drawing (AHCD). Results show that the AHCD can improve the properties of
products due to sub-structural hardening. The tensile strength and equivalent conductivity of the alloy
are 315 MPa and 55.03 % IACS respectively, and are much better than those characteristics of the
alloy produced by the conventional process (295 MPa, 52.5-53.0 % IACS).
From Angel Food Cake to Porous Titanium – A Novel Powder Metallurgical Approach for Metallic Foam Utilizing Food Processing and Ceramic Processing Techniques
Authors: Wong Ka C.
Published: March 2009

Porous Ti6Al4V was attempted to be produced by using the protein forming method. This study
characterizes slurry compositions and processing parameters aimed to obtain porous Ti6Al4V with
open porosity, an interconnected porous networks and controllable pore size. Laboratory egg white
powder was used as a binding and a foaming agent. A porous Ti6Al4V green body was produced
through a gelling process at 80°C and a drying process at 120°C. A good strength porous Ti6Al4V
specimen is available after a protein burnout process in an air atmosphere and a sintering process in
a vacuum environment. Optical microscopy was performed on the porous Ti6Al4V specimens after
each processing step to inspect their porous structure. Carbon and oxygen contents were also
analyzed in the specimens during intermediate processing steps. Optimal temperature for protein
burnout process is identified to be between 400°C to 450°C for an egg white concentration in the
range of 6vol% - 24vol%. Pore sizes approximately 200–700 μm were observed after the sintering
process. These experimental results demonstrate prospects on fabricating porous titanium and other
metals using the protein forming method.
Dependence of Strain Rate and Environment on the Mechanical Properties of the Ni-19Si-3Nb-1Cr-0.2B Intermetallic Alloy at High Temperature
Authors: Fu C.C. , Chung C.M. , Chang L.J. , Chang C.F. , Jang Jason S.C.
Published: March 2009

The results of atmosphere-controlled tensile test in various conditions (with different
strain rate at different temperature under vacuum, air, or water vapor atmosphere) revealed that the
addition of boron and chromium would improve the elongation as well as ultimate tensile strength
(UTS) of the Ni-19Si-3Nb based alloys over a wide range of temperature under air and water vapor
atmosphere. The UTS and elongation can reach to 1270 MPa and 14%, respectively at 873K in each
kind of atmosphere. On contrary, the alloy without boron addition only presents ductile mechanical
behavior in vacuum. This is evident that boron and Cr elements present positive effect on
suppressing the environmental embrittlement in air and water vapor atmosphere from room
temperature to 1073 K for the Ni-19Si-3Nb base alloy. In addition, both of UTS and elongation
present quite insensitive on the strain rate when test at the temperature below 973 K. However, the
UTS exhibits very dependent on the strain rate when test temperature above 973 K, decreasing the
ultimate tensile strength with decreasing strain rate.
Reliable Titanium Aluminide Texture Measurement Using EBSD
Authors: Nave Mark , Inoue Hirofumi
Published: March 2009

γ-TiAl has a tetragonal structure that is almost cubic (c/a ≈ 1.02). As a result of this, the
electron backscatter diffraction patterns (EBSPs) of orientations related by 90°<100] rotations are
almost identical. Reliable orientation measurement during automated EBSD mapping requires
distinguishing very small differences in the positions of certain bands within the EBSPs. EBSD was
used to measure the micro-texture and bulk texture of γ-TiAl hot-deformed under conditions
approximating plane-strain compression. The reliability and accuracy of the indexing was assessed
by inspecting the orientation maps for misindexing and by comparing the texture measured using
EBSD with that measured using X-ray diffraction (XRD). Using Advanced Fit refinement and
high-resolution EBSPs produced reliable and accurate results. Substantial misindexing was present
when the EBSPs were indexed using the Hough transform method alone.
Modification of Ni-Cr-Co-Mo-Nb-Ti-Al Superalloy for USC Power Plant Application at Temperature above 750°C
Authors: Xie Xi Shan , Zhao Shuang Qun , Dong Jian Xin , Smith Gaylord D. , Baker B.A. , Patel Shalesh J.
Published: March 2009

A recent developed Ni-Cr-Co-Mo-Nb-Ti-Al type nickel-base superalloy, INCONEL 740,
has been selected for the application of USC boilers at the temperature above 750°C. This paper
focuses on the structure stability improvement of this alloy. Phase computation by Thermo-Calc has
been adopted to study main influencing factors on precipitating phases of the alloy and the results
show that the ratio of Al/Ti plays an important role. Four new modified alloys in adjustment of Al and
Ti contents and in control of Si level were designed and melted for experimental study. The results
indicate that the modified alloys exhibit more stable structure stability at 750, 800 and 850°C long
time exposure. The newly developed alloy can be adopted for engineering production and application
for USC power plants at temperature above 750°C.
Fabrication of Bi2-xSbxTe3 (x=0-1.5) Thick Film by Centrifugal Deposition
Authors: Aoki T. , Kinemuchi Yoshiaki , Kaga Hisashi , Ito Chihiro , Ishiguro Hirohide , Morimitsu H. , Uchimura Shoji , Watari Koji
Published: March 2009

A Bi2-xSbxTe3(x=0-1.5) thick film thermoelectric element was fabricated using centrifugal
deposition and its Sb content-dependent thermoelectric properties were investigated. When the Sb
content was low (x=0.5), two types of fine structure along the direction of the thickness were
observed. Pole figure measurements revealed that the vicinity of the film surface was composed of
single crystal layers oriented along the c-axis and the vicinity of the interface with the substrate was
composed of randomly orientated layers. As the content of Sb increased, the degree of orientation
improved, and at x=1.5 the entire film was close to a single crystal. A Bi0.5Sb1.5Te3 thick film showed
p-type thermoelectric properties and a thermoelectric power factor of 3.5 ×10-3W/mK2. It was thus
demonstrated that centrifugal deposition can be used to fabricate thermoelectric elements with high
efficiency.
Silicon Nitride/Boron Nitride Composite by Combustion Synthesis
Authors: Zhang Ke , Zhang Qiang , Wang Peng Fei , Bai Ling , Shen Wei Ping , Ge Chang Chun
Published: March 2009

Machinable silicon nitride/ hexahedral boron nitride (Si3N4/h-BN) composites were in-situ
synthesized in a nitrogen (N2) atmosphere by means of combustion synthesis gas-solid reaction with
silicon (Si) powder and h-BN as raw materials. The effect of the volume fraction of h-BN on the
machinable properties of Si3N4/BN composite was studied. The results show that Si powder was fully
nitrified and no residual Si was found. Microstructures by a scanning electron microscopy (SEM)
show Columnar crystals of β-Si3N4 are the main phase and acicular crystals of h-BN disperse β-Si3N4
intergranular. With the increasing of the volume content of h-BN, the machinability of the composite
increases, but the bending strength of composite decreases firstly and then increases. The lowest
bending strength is 84.96MPa at 25% volume fraction of h-BN.
Development of Efficient Metal Catalyst Support
Authors: Muraoka Shouichi , Kitamura Kazuhiro , Kishi Satoshi , Nakazawa Tatuo , Shimizu Yasuo
Published: March 2009

A new wire mesh metallic catalyst support has been studied by using a stainless heat
resistant steel of including aluminum. This catalyst support was improved for the metal honeycomb
catalyst support that had been put to practical use. The wire mesh catalyst support was made in the
following procedures. First, it was made from flat plate made by the stainless steel from the
machining. Second, the low oxygen atmosphere in the heat treatment furnace did the aluminum
extraction processing. Third, the aluminum oxide layer was made on the surface of catalyst support by
furnace in air. Metal honeycomb catalyst has been made for several years by this method. The aim of
this study was to evaluate the aluminum oxide layer on the surface of wire mesh catalyst support. The
aluminum oxide surface was measured using scanning electron microscopy (SEM) and X-ray
reflection diffraction (XRD). This catalyst support has the performance similar to the conventional
metal honeycomb catalyst support.
Negative Thermal Expansion in Mn3Ga(Ge,Si)N Anti-Perovskite Materials
Authors: Sun Ying , Wang Cong , Wen Yong Chun
Published: March 2009

Mn3GaN has anti-perovskite structure and there exists an abnormal thermal expansion
behavior in accompanying with a magnetic transition and variation of electronic transport properties.
Substitution of Ga by Ge(Si) induces the change of the thermal expansion properties and the
corresponding temperature range. The structure, heat capacity, magnetic and electronic transport
properties of Mn3Ga(Ge,Si)N were investigated and discussed.
Densification and α/β Phase Transformation of SHS Si3N4 Containing Al2O3 and Y2O3 during Sintering
Authors: Bai Ling , Ge Chang Chun , Shen Wei Ping , Zhang Ke , Mao X.D.
Published: March 2009

The densification and phase transformation of high α-phase silicon nitride powder
synthesized by SHS with a combination of Y2O3 and Al2O3 sintering additives were investigated. The
densification process occurred rapidly from 1400 to 1500 °C and was nearly finished at 1500 °C.
However, the α-β transformation of silicon nitride progressed rapidly from 1500 to 1600 °C, and
completed at 1600 °C. The phase transformation of silicon nitride lagged behind the densification of
Si3N4 ceramics. It showed that the solution and precipitation process did not play the main role in the
densification of silicon nitride. The sufficient amount of liquid phase was crucial to complete the
densification.
Effect of Oxygen Partial Pressure on Electrical Conductivity of Ca-Ru-O Compounds Prepared by Spark Plasma Sintering
Authors: Keawprak Nittaya , Tu Rong , Goto Takashi
Published: March 2009

Ca-Ru-O compounds were prepared by spark plasma sintering (SPS) using CaCO3 and
RuO2 powders at various molar ratio of Ru to Ca (RRu/Ca). CaRuO3 in a single phase was obtained at
RRu/Ca = 1.0. A non-stoichiometric solid solution range of CaRuO3 was identified at RRu/Ca = 0.7 to
1.0. The electrical conductivity (σ) showed metallic conduction behavior and increased with
increasing RRu/Ca. The electrical conductivity at RRu/Ca = 0.8 to 1.0 increased with decreasing oxygen
partial pressure (PO2) and the PO2 dependence of σ became significant with increasing temperature.
Fabrication and Electrical Property of SiC-AlN Composites
Authors: Hojo Junichi , Nonaka Yuki , Kamada Kai , Enomoto Naoya , Hotta Mikinori , Shirouzu Keita
Published: March 2009

SiC and AlN form a solid solution in the wide compositional range, expectantly leading
to control of the semiconductive property. In the present work, the SiC-AlN composites were
fabricated by sintering process, and evaluated with emphasis on the distribution of SiC and AlN and
electrical property. SiC and AlN powders were mixed at a molar ratio between 90:10 and 10:90, and
sintered at 1900-2100 °C for 30 min under 50 MPa in Ar atmosphere by spark plasma sintering
technique. The sintered bodies reached high densities over 95 % of theoretical, and the grain size
increased with an increase in the sintering temperature and the AlN content. The SiC-AlN
composites had 3C and 2H phases in SiC-rich composition, while 2H phase only in AlN-rich
composition, and the mutual dissolution between SiC and AlN was enhanced at high temperatures.
The electrical conductivity decreased with dissolution of AlN into SiC because of the increase in
band gap.
Frictional Behavior of Glass Fiber Reinforced Polyester under Different Loads
Authors: Quintelier Jan , Van den Abeele Filip , De Doncker Liesbet , De Waele Wim , Degrieck Joris , Samyn Pieter
Published: March 2009

Pultruded glass fibre reinforced polyester where used to investigated the frictional
behaviour of the 45° fibre orientation. Therefore, on a rebuild Pin-on-disc test rig, using composite
discs and steel pins, the frictional behaviour of these materials is investigated. Due to the indicated
fibre orientation, and a simple trigger mechanism, it was possible to distinguish the friction force for
different fibre orientations. The classical know orientations, parallel and perpendicular to the
direction of sliding provided expected results, for both cases. The ~45° orientation, which is
extremely important regarding filament wounded bearings, behaved in both cases similar --
regarding friction force-- in an unexpected way. The friction force of the 45° orientation was higher
in all cases, and the amount was similar to the difference between the parallel and perpendicular
case. These findings yield the conclusion that the 45° orientations cannot be neglected in frictional
studies, and the behaviour of weft-warp structures also determines performance.
Damping Characteristics of a NiMnGa/Polymer Composite Material
Authors: Sun Xiao Gang , Xie Chao Ying
Published: March 2009

NiMnGa alloys are attractive for the magnetic induced shape memory effect, especially as
promising functional elements in smart composite materials and structures. Recently, more attentions
are put on NiMnGa composite materials. In this paper, NiMnGa particles have been dispersed and
oriented in a polymer matrix with high content under magnetic field. The damping behavior of
NiMnGa/polymer composites was investigated in by DMA, contrasting to the pure polymer.
Microstructure Control of Ceramic-Intermetallic Composites by Heat-Treatment before Combustion Synthesis
Authors: Matsuura Kiyotaka , Ohsasa Kenichi , Obara Yuki
Published: March 2009

When mixtures of Fe, Al, Ti and B powders were heated, the combustion synthesis, or
SHS, reaction occurred and produced a TiB2 particle dispersed FeAl-based composite. The TiB2
particle size increased with increasing TiB2 volume fraction from 0.3 to 0.8, which was considered
to be due to the fact that the adiabatic temperature of the reaction increases with the increase in TiB2
concentration in the composite due to the large formation enthalpy of TiB2. The TiB2 particle size
decreased with increasing preheating time, temperature and pressure before the SHS reaction. It was
suggested that partial reaction between elemental powders before the SHS reaction reduced the
adiabatic temperature and hence the TiB2 particle size. The Vickers hardness of the composite
varied from 500 to 2000 depending on the microstructure. This method was applied to the
production of TiC-FeAl, TiC-Fe, TiB2-Fe composites.
Texture Aspects of Deformation Processes under Equal-Channel Angular Pressing of Metals
Authors: Perlovich Yuriy , Isaenkova Margarita , Fesenko Vladimir , Grekhov M.
Published: March 2009

The texture of Ti and Zr rods, subjected to equal-channel angular pressing (ECAP) by
routes C and BC, is considered as a source of information about the actual loading scheme,
operating mechanisms of plastic deformation, the structure condition of material. Processes of grain
reorientation under rolling and ECAP are compared and distinguishing features of the latter are
revealed. Effects of grain fragmentation and dynamic recrystallization on the texture are discussed.
Development of Substructure Non-Uniformity under Equal-Channel Angular Pressing
Authors: Isaenkova Margarita , Perlovich Yuriy , Fesenko Vladimir , Grekhov M.
Published: March 2009

By taking into account an interconnection between substructure non-uniformity and substructure
anisotropy, a new approach to study the substructure non-uniformity is developed as applied
to metal rods, subjected to Equal-Channel Angular Pressing (ECAP). The X-ray method of
Generalized Pole Figures (GPF) was used for construction of distributions of substructure parameters.
Some experimental data are presented, illustrating possibilities and efficiency of the used approach.
Semisolid Forging of Cast Iron Using Rapid Resistance Heating
Authors: Maki Seijiro , Suzuki Kazuhito , Mori Kenichiro
Published: March 2009

Feasibility of semisolid forging of cast iron using rapid resistance heating was
experimentally investigated. Gray pig iron FC250 and spheroidal graphite cast iron FCD600, whose
carbon equivalents are both 4.3% in mass, were used for the experiments. Since these cast irons
have a narrow semisolid temperature range, an AC power supply with an input electric energy
control function was used. In this study, the resistance heating characteristics of the cast irons were
firstly examined, and then their semisolid forging experiments were conducted. In the forging
experiments, the conditions of the forgings such as microstructures and hardness properties were
examined, and the feasibility of the semisolid forging of cast iron using resistance heating was
discussed. As a result, it was found that the method presented here is highly feasible.
Effect of Structure on Hot Tearing Properties of Aluminum Alloys
Authors: Eskin Dmitry G. , Katgerman Laurens
Published: March 2009

Hot tearing is a significant problem upon direct-chill casting of high-strength aluminum
alloys. The occurrence of hot cracks is related to the thermal contraction of the solid phase and to
the lack of feeding by the liquid phase during solidification. It has been identified that structure
features such as grain size and amount of nonequilibrium eutectics influence both phenomena
involved in hot tearing. Experimental and computer-simulation results are presented for a range of
model and commercial aluminum alloys. The results are obtained both during special small-scale
experiments and during industrial-scale direct-chill casting. It is shown that grain refinement
reduces hot tearing susceptibility of aluminum alloys through the related decrease of the temperature
of thermal contraction onset and increased permeability of the mushy zone. The effects of process
parameters on hot tearing are also discussed.
A DTA Study on HVOF Thermally Sprayed WC–M Coatings
Authors: Sohi M. Heydarzadeh , Khameneh Asl Shahin , Hokamoto Kazuyuki , Rezvani M.
Published: March 2009

Five types of tungsten carbide based powders with different chemical compositions (WC-12Co,
WC-17Co, WC-10Ni, WC-10Co-4Cr and WC- 20Cr-7Ni) were deposited onto ST37 mild steel
substrate using high velocity oxy fuel (HVOF) spray technique. The feedstock powders and sprayed
coatings were studied by using X-ray diffraction (XRD), and differential thermal analyzing (DTA).
The results were shown during HVOF thermal spraying, WC-M powders become partially melted
before being sprayed on the surface of the substrate with supersonic speed. In these types of
coatings, the crystallographic structures are normally non equilibrium, because the cooling rates of
the deposited splats are very high due to the cold substrate acting as a thermal sink. These partially
melted powders are then rapidly solidified to an amorphous phase. XRD analysis showed that the
amorphous phase was existed in all of the as sprayed coatings. The amorphous phase in WC-12Co,
WC-17Co and WC-10Ni coatings was transformed to crystalline phases by heat treatment at high
temperature. Heat treatment of these coatings at high temperature also resulted in partially
dissolution of WC particles and formation of new crystalline phases. In cobalt base coatings, the
new phases were eta carbide phases like Co6W6C and Co3W3C but in WC-10Ni coating a NiW
intermetallic phase was formed. Heat treatment of WC-10Co-4Cr and WC-20Cr-7Ni coatings did
not change the amorphous phases in these coatings. Differential thermal analysis of cobalt
containing coatings revealed an exothermic reaction at approximately 880°C. This exothermic
reaction may be related to the transformation of the amorphous phase to eta phases. On the contrary,
DTA analysis of feedstock powders of these coatings showed an endothermic reaction at
approximately 1000°C. DTA analyses of nickel containing cermets also showed similar results.
Differential thermal analysis of chromium containing cermets did not show any noticeable
exothermic or endothermic reactions.
Ultrasonic Nondestructive Approach on Fiber Orientation Inspection in CFRP Composite Laminates
Authors: Yang In Young , Yang Yong Jun , Lee Kil Sung , Hsu David K. , Im Kwang Hee
Published: March 2009

Owing to the advantages associated with their very large strength-to-weight and stiffnessto-
weight ratios, composite materials are attractive for a wide range of applications. Increasingly,
high performance engineering structures are being built with critical structural components made
from composite materials. In particular, the importance of carbon-fiber reinforced plastics (CFRP)
has been generally recognized in both space and civil aircraft industries, and CFRP composite
laminates are widely used. It is very important to detect fiber orientation error in orthotropic
composite laminates because the layup of a CFRP composite laminates affects the properties of the
laminate, including stiffness, strength and thermal behavior. In this study, a new approach was
investigated on detection of fiber orientation with using two longitudinal and a shear wave
ultrasonic transducers for the orthotropic composite laminates. During testing, the most significant
problem is that the couplant conditions do not remain the same because of changing the viscosity of
the couplant. Therefore, making a design for generating shear wave with longitudinal transducers
would greatly aid in alleviating the couplant problem. A pyramid with an isosceles triangle was
made of aluminum in order to generate shear waves using two longitudinal transducers based on
ultrasonic-polarized mechanism. It is found that the shear wave was very sensitive to fiber of CFRP
composite. Finally, a CFRP composite material was nondestructively characterized in order to
measure fiber orientation error area using automated data acquisition C-scan system.
Design and Experiment of Compact Projectile Accelerator Driven by Explosives
Authors: Saburi Tei , Kubota Shiro , Yoshida Masatake , Simangunsong Ganda M. , Wada Yuji , Ogata Yuji
Published: March 2009

This paper presents the design of a compact size projectile accelerator, and its
application. To meet the various needs such as a compact body size to use under various experimental
conditions, an easy maintenance for repetitive experiments during a certain period, and a capability of
the velocity control, the compact accelerators were newly designed with a direct explosive drive
method. Two different types of accelerator were designed: a PMMA accelerator and a metal
accelerator. The pictures of the projectile shoot using the designed accelerators were recorded by
SHIMADZU HyperVision HPV-1 high-speed video camera. As a result, it was recognized that the
PMMA accelerator was failed to accelerate the projectile, while the metal accelerator succeeded to
accelerate it effectively. The accelerating performance of the metal accelerator was further
investigated. The explosives for projectile acceleration were Emulsion explosive and Composition
C4 explosive weighing 5 to 35g. It was found that the metal accelerator has the capability to control
the projectile velocity adjusting the weight of the explosives, and there is an approximate linear
correlation between them in our experimental range. A series of impact tests on 5052S aluminum
alloy targets was examined using the accelerator.
The Industrial Applications of Underwater Shock Wave
Authors: Itoh Shigeru
Published: March 2009

The industrial applications of under shock wave have been investigated in our center.
This paper concerns with the improvement of foods and wood using underwater shock wave.
Underwater shock wave is easily generated by means of explosion of explosives or high voltage
electric discharge in water. A detonating fuse and an electric detonator were used for generation of
underwater shock wave, and apples were used as food sample for food processing experiments. The
behavior of underwater shock wave was investigated by optical observations. The extraction and the
amount of phenolic compounds in apple juice obtained from the shock treated sample were higher
than that of control samples. It is considered that the underwater shock wave treatment for apples
has a big possibility in food processing. The results of coffee bean and other food processing by
underwater shock wave were presented at the conference. Moreover the properties of wood were
well improved by shock loading. The resistance of wood has been improved significantly.
Planar Defects and their Role in Physics-Mechanical Properties of Ordered Alloys and Intermetallides
Authors: Starostenkov Mikhail D. , Dudnik Evgenia , Popova Galina , Chernykh Evgeniya
Published: March 2009

Ordered alloys and intermetallides are important constructional materials, because they
have a unique property – positive temperature dependence of yield stress. It is known that antiphase
boundaries and washing effects of order, structures and concentrations of components near the
boundaries are of great impotence in the appearance of positive temperature dependence. But
superstructures have not only APB but also APB tubes, APB stripes. Their role is also important in
physical and physics-mechanical properties of ordered alloys and intermetallides. The paper
presents the classification of all the types of planar defects and their local properties for some alloys
of different superstructure types.
Cohesive Zone Model and GTN Model Collation for Ductile Crack Growth
Authors: Kozák Vladislav , Dlouhý Ivo , Chlup Zdeněk
Published: March 2009

The micromechanical modelling encounters a problem that is different from basic
assumptions of continuum mechanics. The material is not uniform on the microscale level and the
material within an element has its own complex microstructure. Therefore the concept of a
representative volume element (RVE) has been introduced. The general advantage, compared to
conventional fracture mechanics, is that, in principle, the parameters of the respective models
depend only on the material and not on the geometry. These concepts guarantee transferability from
specimen to components over a wide range of dimensions and geometries. The prediction of crack
propagation through interface elements based on the fracture mechanics approach (damage) and
cohesive zone model is presented. The cohesive model for crack propagation analysis is
incorporated into finite element package by interface elements which separations are controlled by
the traction-separation law.
Bending and Contact Strength of a Si3N4+SiC Micro/Nano Composite
Authors: Dusza Ján , Kašiarová Monika , Hegedűsová Lucia , Hnatko Miroslav , Šajgalík Pavol
Published: March 2009

Bending and contact strength of a carbon derived in-situ reinforced Si3N4-SiC micro/nanocomposite
have been investigated. Four-point bending strength was measured using specimens with different
effective volume and Weibull statistical analysis has been used for characterization of the strength
values in the form of characteristic strength and Weibull modulus. The characteristic strength values
of the investigated composite were σ0 = 675 MPa and σ0 = 832 MPa with the Weibull modulus of
6,4 and 8,6 for the specimens with effective volume 15,9 mm3 and 1,28 mm3 respectively. Contact
strength of the investigated material was carried out using sphere on sphere and roller on roller
methods and the obtained results are σ0S = 1997 MPa, σ0R = 1242 MPa, and mS = 17,1 mR = 6.
Fracture origins in the specimens with effective volume of 15.9 mm3 tested in four-point bending
were surface and volume located technological defects with dimensions from 10 μm to 180 μm,
mainly in the form of clusters of pores and large SiC grains. Fracture mirror sizes were measured
and the mirror constant was calculated. Fracture origins in the specimens with effective volume of
1.28 mm3 tested in four-point bending were surface (subsurface) defects with the same type as for
the specimens with a higher effective volume. The fracture during the contact strength test
„roller/roller“ has been initiated under the surface of the specimens and during the contact strength
test „sphere/sphere“ by creation and growth of the cone cracks to critical size.
Gold Nanolayers Prepared on Poly(ethyleneterephtalate)
Authors: Siegel Jakub , Slepička Petr , Kotál Vladimír , Novotná Miroslava , Bláhová Olga , Švorčík Václav
Published: March 2009

Ablation, water etching and gold coating were studied on poly(ethyleneterephtalate)
(PET) exposed to DC Ar plasma for 240 s at 8.3 W power. Au layers were sputtered on pristine and
modified PET and their adhesion and topography were investigated. The roughness and changes of
topography after plasma treatment, subsequent water etching and gold coating were followed using
AFM microscopy. The thicknesses of ablated layer and water dissolved layer were determined using
gravimetry. A nanoindentor was used to perform microstratch tests of sputtered layers. Water
dissolving of thin layer after plasma treatment was confirmed by FTIR spectroscopy. We have
found that under the present experimental conditions ca 30 nm thick layer of PET is plasma ablated.
The surface topography changes dramatically and surface roughness increases. Another ca 16 nm
thick layer was removed under present laboratory conditions after 24hour water etching. Subsequent
coating with 50 nm thick gold layer increases surface roughness in all cases of surface modification.
Effect of Vibrations on Lifetime of Ni Base Single Crystals Subjected to Tensile Stress
Authors: Kunz Ludvík , Lukáš Petr , Mintách Rastilav
Published: March 2009

The lifetime of superalloy single crystals CMSX-4 and CM186LC subjected to tensile
mean stress with vibrations at high temperatures has been experimentally studied. Both beneficial
and detrimental effect of cyclic stress component has been observed. An increase of lifetime due to
superposition of cyclic component on the mean stress is explained by reduction of creep rate due to
vibrations. The onset of decrease of lifetime with increasing stress amplitude is observed when the
fatigue damage due to initiation and propagation of fatigue crack overbalances the beneficial
influence of high frequency cycling.
The Microstructural Properties of Microalloyed Steel after Plastometric Testing
Authors: Gajdzica Tomáš , Kliber Jiri , Kotas Milan
Published: March 2009

With the aid of an ASC-type finishing line (Automatic System Control) and continuous cooling of
the rolled stock in water boxes, modern continuous light mills enable thermomechanical
(controlled) rolling of SBQ-type rods (Special Bar Quality). During the thermomechanical forming
(at different temperatures or cooling rates etc.), one can analyze the quality parameters of roundsection
steel bars. In order to obtain better understanding to the forming conditions (temperature,
strain and strain rate) and the possibility of cooling (related to its rate and time), an experiment
involving continuous and discontinuous testing by means of a Gleeble plastometer was suggested.
After its implementation, the attention was focused on the mathematical interpretation of the stressstrain
characteristics of the steel and on metallographic observation of microstructural changes. The
results achieved are of universal meaning and contribute to the theoretical understanding of
controlled forming.
Effect of Intercritical Annealing on Structure and Mechanical Properties of 10GN2MFA Grade Steel
Authors: Kander Ladislav , Matocha Karel , Korcak Ales
Published: March 2009

The effect of intercritical annealing of 10GN2MFA grade steel on mechanical properties and impact
notch toughness is studied in this paper. This type of low alloy banitic steel is used for production of
collector bodies of steam generators for nuclear power station of VVER type. This article is focused
on optimalization of fundamental utility properties and heat treatment process of the steel under
investigation to increase toughness and critical temperature of brittleness. An intecritical annealing
has been chosen as a useful tool for such improvement. Mechanical properties and impact notch
toughness values after the intercritical annealing and conventional heat treatment regimes are
compared. Effect of simulation of stress relieving including minimum and maximum allowable
heating regimes are studied too. Intercritical annealing was added to the conventional quality heat
treatment process, between quenching (normalizing) and tempering. The application of intercritical
annealing improved the impact toughness significantly, an increase in the upper shelf energy and a
decrease in transition temperature of steel under investigation.
Relationships between Microstructural Parameters and Properties of 15NiCuMoNb5 Grade Steel Used for Special Industry Applications
Authors: Kander Ladislav , Matocha Karel , Sobotka Jaromír
Published: March 2009

This article is focused on optimization of fundamental utility properties and technological process
of advanced low alloy steel 15NiCuMoNb5 used for power engineering mainly for production of
large capacity steam boilers. Consequently problem critical locality in weld after post weld heat
treatment is studied. Optimization of welding technology is proposed. Fracture behaviour of welded
joint made from boiler plates 80 mm in thickness of 15NiCuMoNb5 type steel after N + T PWHT
regime after welding procedure were studied. Stable crack growth measurement and evaluation of
fracture toughness of base material as well as weld metal in temperature region from 0 up 350°C
were carried out. Unstable cleavage fracture and fracture toughness KJc of both parts of welded joint
at test temperatures cover the transition region were evaluated. The reference temperature T0
approach was used for evaluation of temperature dependence of fracture toughness in transition
range.
Fatigue Striations and Fissures in 2024-T3 Aluminum Alloy
Authors: McEvily A.J. , Endo Masahiro , Cho S. , Kasivitamnuay J. , Matsunaga Hisao
Published: March 2009

A study has been made of the striations and fissures developed in the aluminum alloy
2024-T3 during fatigue crack growth. Fissures were found to form on inclined facets. They were
uniformly spaced as the result of a shielding process. Striation spacings were in accord with da/dN
values at the higher levels of K investigated, but at low K levels striation spacings were larger
than the corresponding da/dN values. The percentage of the fracture surface containing striations
varied with the K level, ranging from less than 1 % at low K levels to 80 % at higher K levels.
The reason for the discrepancy between the spacing of striations and the corresponding da/dN values
is discussed.
Dislocation Structures in Nickel Based Superalloy Inconel 792-5A Fatigued at Room Temperature and 700°C
Authors: Petrenec Martin , Obrtlík Karel , Polák Jaroslav , Man Jiří
Published: March 2009

Dislocations structures were studied using transmission electron microscopy in specimens
of cast polycrystalline nickel based superalloy Inconel 792-5A cyclically strained up to failure with
constant total strain amplitudes at temperatures 23 and 700 °C. Spatial arrangement of dislocations
in individual grains was determined using the technique of oriented foils. Planar dislocation
arrangements in the form of bands parallel to the {111} planes were observed in specimens cycled
at both temperatures. The bands showed up as thin slabs of high dislocation density cutting both the
γ channels and γ´ precipitates. They correspond to areas of cyclic slip localization. Experimental
results concerning the dislocation structure are used to discuss the effect of temperature on the
cyclic stress-strain response and fatigue life.
Monte Carlo Simulation of Normal Grain Growth in Three Dimensions
Authors: Zöllner Dana , Streitenberger Peter
Published: March 2009

A Monte Carlo algorithm for single-phase normal grain growth has been implemented,
which allows one to simulate and observe the temporal development of large grain microstructures
in three dimensions. The relaxation process to the self-similar coarsening regime has been studied
by following the temporal development of quantities like the average grain size, the standard
deviation of the grain sizes and topological correlations.
The Effect of Mean Stress and Thermo-Mechanical Induced Stress on Micro-Crack Initiation: An Analysis Based on Experiments and DD Simulation Results
Authors: Robertson Christian F. , Déprés Christophe , Fivel Marc
Published: March 2009

The combined effect of cyclic thermal shocks and static tensile loading is investigated, in a 304L
stainless steel. During these experiments, the stress state in the cylindrical specimen walls is nearly
equi-biaxial (σZZ ≈ σθθ). In dislocation dynamics (DD) simulations carried out with σZZ = σθθ, the
predominant slip directions b are nearly aligned with the free surface normal vector n, regardless of
their associated activation ratio (A.R.). This effect is related to the "surface connected volume"
(SCV) of the predominant slip systems. Hence, surface grains with n = <110> possess "large SCV
slip systems" and therefore, constitute preferential sites for micro-crack initiation in thermal fatigue.
During the tests, a marked effect of the superimposed static tensile loading (or mean stress) is also
noted. This effect is explained with the help of DD simulations performed with a positive mean
stress: slip irreversibility in the individual persistent slip bands systematically augments with
increasing mean stress.
Simulation of the Cyclic Response of 316L Single Crystals and Polycrystal Using Three Dimensional Elastic-Plastic Crystalline Finite Element Computations
Authors: Ferrié Emilie , Sauzay Maxime
Published: March 2009

In the work presented here an elastic-plastic crystalline finite element method is used to
simulate the cyclic behavior of 316L austenitic stainless steel single crystals and polycrystal. The
evolution of the back stress on each slip system is described using a non linear kinematics hardening
law to account for the hardening induced by long range dislocation interactions. As the contribution
of short range interactions is assumed to be negligible, the value of the friction stress is kept
constant. Three dimensional finite element calculations are performed to simulate the cyclic stress
strain curves in the case of a single crystal oriented for multiple slips, as well as for the case of the
polycristal. Simulations are compared to experimental data. They seem to be satisfactory for low
strain values (εp\2 <10-3) whereas, for εp\2 >10-3, they underestimate the hardening observed
experimentally.