bluuebunny/crossref_metadata_2025 huggingface dataset:
Spherulitic Structures in Bisphenol-A Polycarbonate Crystallized at High Pressure
Authors: Lu Jun , Oh Il Kwon , Huang Rui , Wang Xuan Lun
Published: March 2009

The high-pressure crystallized bisphenol-A polycarbonate (BAPC) and BAPC / dioctyl
phthalate (DOP) blend samples were investigated using wide-angle X-ray diffraction (WAXD),
differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The results
showed that the rate of the crystallization of BAPC could be greatly increased by the introduction of
DOP at high pressure. Morphologies of spherulites of BAPC with different characteristics were
observed during the investigation, including ellipsoids ascribed to the liquid-liquid phase separation
via spinodal decomposition, sheaf-like and spherical features corresponded to the different stages of
spherulitic growth, and stereo-open forms with a three-dimensional structure. The disclosed entities,
some of which have potentials in functional applications, may promote the understanding of the
formation process and mechanism of polymer spherulites.
Strain Aging of Heavily Drawn Pearlitic Steel Wires
Authors: Min Na , Gu Yi Jia , Jin Xue Jun
Published: March 2009

The strain aging of heavily drawn pearlitic steel wires has been studied by means of
electrical resistivity mearsurement. The kinetic of the early stage of strain aging after being drawn to
true strain 2.89 is described by a Johnson-Mehl equation. The apparent activation energy ΔH is
estimated as 31.7kJ/mol. The results indicate that the mechanism of the early stage of strain aging of
heavily drawn pearlitic steel correlates with the formation of interstitial solute atoms-vacancy pairs.
ECCI Observation of Dislocation Structure Formed around an Intergranular Fatigue Crack in Copper
Authors: Kaneko Yoshihisa , Ishikawa M. , Hashimoto Satoshi
Published: March 2009

A fatigue crack growth test was conducted in a polycrystalline copper. Dislocation
structure formed near an intergranular fatigue crack was investigated by electron channelling contrast
imaging (ECCI) method. The ECCI method enables us to observe dislocations lying under surface
using a scanning electron microscope. The fatigue crack in the copper specimen was grown along
both grain boundaries and slip bands inside grain. The ECCI observations revealed that both the vein
dislocation structure and the cell structures were formed near the grain boundaries. The formations of
different dislocation structures near boundaries could be interpreted in terms of the plastic strain
incompatibility.
Effect of Ca and Sr Content on Elevated Temperatures Mechanical Properties of a Cast AZ91 Magnesium Alloy
Authors: Takeuchi Ippei , Hirai Kinji , Takigawa Yorinobu , Uesugi Tokuteru , Higashi Kenji
Published: March 2009

The effect of Ca and Sr content on the microstructure and mechanical properties of a cast AZ91
magnesium alloy is investigated. Ca and Sr additions in AZ91 magnesium alloy are expected high
creep resistance. The microstructure of the alloy exhibits the dendritic α-matrix and the
second-phases forming networks on the grain boundary. Tensile tests at elevated temperatures
between 448 and 523K reveal that the creep resistance was improved with increasing the additional
amount of Ca, especially more than 1.0wt%. From the perspective of grain refinement effect, it is
expected that the additions of Ca and Sr to AZ91 magnesium alloy not only improve creep
resistance but also improve mechanical properties at room temperature.
Influence of Initial Texture on Twin Formation and Plastic Deformation of Rolled AZ31 Mg Alloy
Authors: Lee B.H. , Park S.H. , El Mehtedi Mohamad , Evangelista E. , Lee Chong Soo
Published: March 2009

The influence of initial texture on the formation of primary twin system of AZ31
Magnesium rolled plate was investigated in this work. Uniaxial compression tests were carried out
on samples cut along the rolling direction (RD) and normal direction (ND) of rolled AZ31 Mg plate
at various temperatures (RT, 150, 200, 250, 300, 350, 400, 450°C) with the fixed strain rate
(0.01s-1). The results showed that the primary twinning system of AZ31 Mg alloy (c-axis extension
twin) occurred actively in the RD compression specimens, which promoted homogeneous
deformation as compared to the ND compression specimens. The effect of temperature on the
formation of deformation twins was also investigated, and slip/twin transition temperature was
found to be 250°C.
Thermodynamic Analysis of Nb-Cr Powders of Mechanical Alloying
Authors: Nie Xiao Wu , Lu Shi Qiang , Wang Ke Lu
Published: March 2009

In this study, Nb-Cr binary mixtures were prepared by mechanical alloying. And
mechanical alloying process of mixed Nb-Cr(1:2) powders was studied, and the phases of milling
powders analyzed by XRD and SEM. It has been found that the powders form solid solution first, then
amorphous phase appeared gradually and crystallization of amorphous takes place with the different
milling time. A thermodynamic model of MA of Nb-Cr system was developed based on Miedema
Semi-experimental theory to explain the phase transformations of Nb-Cr system during milling.
Using Miedema semi-empirical model the free energies of the ordered Laves-phase NbCr2
intermetallics, solid solution and amorphous alloy were calculated. From XRD and SEM analysis of
Nb/2Cr powders prepared by mechanical alloying in a planetary ball milling, it was found that the
calculated results were in accordance with the experiments.
Crystal Structure Variation of Ru2Si3 Upon Alloying with Mn
Authors: Koyama Tatsuya , Ishida Akira , Kishida Kyosuke , Tanaka Katsushi , Inui Haruyuki
Published: March 2009

Manganese-alloyed Ru2Si3-based alloys with various alloy compositions have been
prepared and the phase relationships of these alloys have been investigated as a function of the Mn
concentration using X-ray powder diffraction, scanning electron microscopy and transmission
electron microscopy. A series of Ru1-xMnxSiy chimney-ladder phases is confirmed to be formed over a
wide compositional range (x ≥0.12). These chimney-ladder phases are considered to be formed to
stabilize the HT-Ru2Si3 chimney-ladder phase through the substitution of Ru with Mn. The
compositions of the chimney-ladder phases are, however, significantly deviated from the idealized
composition satisfying the valence electron concentration rule: VEC=14.
In Situ Synthesis of TiB2-TiCx Ceramic Matrix Composites by Hot Isostatic Pressing
Authors: Zhu De Gui , Sun Hong Liang , Wang Liang Hui
Published: March 2009

TiB2-TiC ceramic matrix composites were fabricated by in situ synthesis under hot
isostatic pressing (HIP) with 3TiH2-B4C and 11TiH2-3B4C being the raw materials, respectively. The
XRD analysis indicates that the samples synthesized from 3TiH2-B4C have TiB2 and TiC phases,
while those from 11TiH2-3B4C have not only TiB2 and TiCx phases, but also Ti3B4 phase. TiB2-TiCx
ceramic matrix composites obtained from 11TiH2-3B4C have better mechanical properties than those
from 3TiH2-B4C. The microstructures of the composites are investigated with SEM and TEM. TiB2
grains are platelet grains; Ti3B4 grains have two different morphologies. Ti3B4 phases are formed
through two different paths: fine grain Ti3B4 is formed through TiB+B=Ti3B4 at low temperature;
large plate-like grain Ti3B4 is formed through TiB2+TiB=Ti3B4 at high temperature.
Electromechanical Properties of NKN-5LT Multilayer Actuator
Authors: Kim Min Soo , Jeong Soon Jong , Song Jae Sung
Published: March 2009

Li2O excess 0.95(Na0.5K0.5)NbO3-0.05LiTaO3 (NKN-5LT) ceramics were developed by
conventional sintering method. Abnormal grain growth in NKN-5LT ceramics was observed with
varying Li2O content during sintering. In the 1 mol% Li2O excess NKN-5LT samples sintered at 1000
oC for 4h in air, electromechanical coupling factor and piezoelectric constant of NKN-5LT ceramics
were found to reach the highest values of 0.37 and 250 pC/N, respectively. Lead-free piezoelectric of
the composition 1 mol% Li2O excess NKN-5LT were fabricated. 10×10×3 mm3 size multilayer
ceramic actuators (MLCA) were fabricated by conventional tape casting method. The displacement of
the MLCA was ~ 1 μm at 150 V. These results show that the NKN-5LT ceramics with reasonable
good piezoelectric properties have the potential to become the next generation material for a wide
range of electro-mechanical transducer applications.
H2/CO2 Gas Separation Characteristic of Zeolite Membrane at High Temperature
Authors: Kwon Woo Teck , Kim Soo Ryong , Kim Eun Bi , Bae Seong Youl , Kim Y.
Published: March 2009

Due to the need for CO2 sequestration associated with H2 production from fossil fuels,
zeolite membrane are very promising due to their low cost, high stability and high permeance.
Recently, the faujasite(FAU), the silica/aluminophophate(SAPO-4) framework family of zeolite
have been studied for CO2 gas separation. In our study, ZSM-5 membrane was prepared on the
porous alumina support using a hydrothermal technique. The thickness of zeolite membrane was
controlled by the hydrothermal reaction time and temperature. The prepared zeolite membranes
were characterized with SEM and thin film XRD. The hydrogen permeability and selectivity toward
carbon dioxide gas were 0.6x 10-6 mole/m2.s.pa and 3.16, respectively. The hydrogen selective
zeolite membranes show promising application in hydrogen separation from coal gasification such
as Integrated Gasification Combined Cycle (IGCC).
Continuous Cooling Transformation Behavior of High Strength Low-Alloyed Cold Rolled Sheet Steel
Authors: Liu Hao , Zhong Ding Zhong , Zhao Long Qi , Peng Tao , Wu Li Xin , Zeng Jing
Published: March 2009

The dilatometry curves and the critical phase transformation temperatures of high strength
low-alloyed (HSLA) cold rolled sheet steel were determined by thermal simulation test machine. The
samples were austenitized at 900°C,deformed at 40% of deformation and cooled at different rates of
0.1°C/s~ 60°C/s. The continuous cooling transformation (CCT) diagram under deformation condition
can be drawn. The results showed that the critical phase transformation temperatures are as follows:
Ac3=900°C, Ac1=735°C, Ar3=825°C, Ar1=695°C. A few amount of martensite in high strength
low-alloyed cold rolled steel can be obtained at the cooling rate of 60°C/s. The experimental data
provide the technical references for rolling control, cooling control and heat treatment in real
production.
Hydrogen Separation Characteristics of SiC Nanoporous Membrane at High Temperature
Authors: Kim Y. , Kim Eun Bi , Kim Soo Ryong , Suh Moo Hyun , Choi Doo Jin , Kwon Woo Teck
Published: March 2009

Ceramic membranes having less than 1nm size pores have great potential for gas
separation at high temperature due to their good thermal stability. Moreover, nanoporous silicon
carbide membrane has potential application under hydrothermal condition at high temperature
since it is highly stable at high temperature. In this research, nanoporous SiC membrane has
been developed on porous alumina support using preceramic polymer. Pore size of the SiC
membrane was controlled using polystylene(PS) as the pore forming agent. The SiC membrane
having controlled pore size was characterized with SEM, EDS, FT-IR, XRD and pore size
measurement. The hydrogen permeability and selectivity toward nitrogen gas of the developed
membrane were 0.3 x 10-6 mole/m2.s.pa and 4.1, respectively. The nanoporous hydrogen selective
SiC membrane shows promising application in membrane reactor for steam reforming reacti
on of natural gas, water gas shift reactions and hydrogen separation from coal gasification such
as Integrated Gasification Combined Cycle (IGCC).
Development of Hybrid FRP-Concrete Composite Compression Members
Authors: Joo Hyung Joong , Lee Seung Sik , Yoon Soon Jong , Park Ju Kyung , Shin Kwang Yeoul
Published: March 2009

The concrete-filled steel tubes have been widely used in buildings and civil structures.
However the corrosion of the steel tubes results in the loss of load carrying capacities of the members
and, therefore, there is a need for regular maintenance. To mitigate such maintenance issues and
prevent the loss of load carrying capacity, FRP composite were suggested as the candidate material. A
number of research works has shown that the use of FRP tubes produced by filament winding
technique was very effective on the improvement of compressive strength of the concrete-filled FRP
tubes (CFFT). However the filament wound FRP tubes did mot contribute to the increase of the
flexural strength of a CFFT. In this paper, a new type of FRP tube which consists of several pultruded
open sections assembled by filament winding technique is proposed to improve compressive strength
as well as flexural strength of a CFFT. The load carrying capacity of proposed CFFT is discussed
through the analytical investigation.
Study of High Temperature Wear Resistance of Hot Work Steel for Magnesium Alloy Die Casting
Authors: Li Wen Zhen , Qu Nan
Published: March 2009

The wear properties of TFHS-1 hot work steel developed by Tsinghua University for
magnesium die casting application was studied at elevated temperature with the help of GWY-2000
high temperature wear tester. The result showed that the oxidation wear is the main wear mechanism
at high temperature with dry abrasion, which was also accompanied by some extent of adhesive wear
and abrasive wear. Heat treatment conditions of TFHS-1 steel have an important effect on its
anti-abrasion properties. In this paper, the higher temperature of tempering may result in the better
wear resistance.
Structural Behavior of Polymer Mortar GFRP Composite Pipe
Authors: Nam Jeong Hun , Lee Seung Sik , Yoon Soon Jong , Ok Dong Min , Kim Ju Bum
Published: March 2009

This paper presents the results of experimental and analytical investigations on the
behavior of GFRP pipes used in the water supply pipeline systems. The pipes consist of two filament
wound outer GFRP tubes and polymer mortar between the tubes. Parallel plate loading tests were
conducted and the test results were compared with predicted results. The load-deflection prediction
was conducted by the FE analysis and the conventional strength of materials approach. It was shown
that the results obtained by the experiment and analysis were agreed well.
Physical Characteristic of Ready Mixed Concrete with Different Replacement Ratio of Recycled Aggregate
Authors: Yoon Seung Joe , Seo Soo Yeon , Lee Woo Jin
Published: March 2009

Researches until now about recycled aggregate have mainly focused on illuminating
physical properties and mechanical behaviors of recycled aggregate by experimenting on small
batches of mixing. Unfortunately this kind of mixing does not necessarily fit the reality where a large
amount of ready-mixed concrete is often made. Therefore, this study carried out an experiment by
having a ready-mixed concrete manufacturing company mix a large amount of recycled aggregate that
satisfies quality standard set by the MCT of Korea, then verifying the behaviors of recycled aggregate
concrete. The target concrete compressive strength was selected as 24MPa had a slump flow for
120±25mm and air content of 5.0±1.5%, that is used most in site. The main experiment variable of
this study is to replacement ratio of recycled aggregate(RA). The 27 test specimens were designed
with recycled aggregate replacement ratio that had range of coarse recycled aggregate(CRA), 0, 10,
20, 30, 40, and 50%. The result shows that replacing the natural aggregate with the recycled one up to
the ratio of 30% satisfies the quality standard for mixing concrete properly.
Fabrication of Sandwich Structure with Superplastic Forming Process from Diffusion Bonded Ti-6Al-4V Sheets
Authors: Lee Ho Sung , Yoon Jong Hoon , Yi Yeong Moo , Shin Dong Hyuk
Published: March 2009

It is well known that the utilization of superplastic characteristics in manufacturing process
makes many of aerospace components lighter and stiffer. The weight saving is vitally important
especially for aerospace application and even more weight saving is possible when the superplastic
forming is carried out with diffusion bonding. In this study, the lightweight sandwich structure was
fabricated with superplastic forming(SPF) process from diffusion bonded(DB) Ti-6Al-4V sheets. The
solid state diffusion bonding process was conducted in non-vacuum environment under a pressure of
4MPa for 60 minutes at 875°C and the superplastic forming process was followed for another 40
minutes. Good solid state bonding interface have been observed in microstructure observation and the
sandwich structure was successfully manufactured. It is important to note that the forming conditions
of present study are more practical for application than the previously published conditions, which
require vacuum environment, higher temperature and/or pressure.
The Effect of Isothermal Forging Process Parameters on the Microstructure and the Properties of TA15 Near α Titanium Alloy
Authors: Guo Hong Zhen , Zhao Zhang Long , Wang Bin , Yao Ze Kun , Liu Ying Ying
Published: March 2009

In this paper the effect of isothermal forging process parameters on the microstructure and
the mechanical properties of TA15 titanium alloy was researched. The results of the tests indicate
that, in the range of temperature of 850 °C~980 °C and deformation degree of 20%~60%, with the
increase of temperature or deformation, as the reinforcement of deformation recrystallization, the
primary α-phase tends to the spherical shape and secondary α-phase transforms from the acicular
shape to fine and spherical shape with disperse distribution, which enhance the tensile properties at
room and high temperature. With the increment of forging times, the spheroidization of primary
α-phase aggrandizes and secondary α-phase transforms from spherical and acicular shape to wide
strip shape, which decrease the tensile properties at room and high temperature. The preferable
isothermal forging process parameters are temperature of 980 °C, deformation degree of 60%, and
few forging times.
Recrystallization Characteristics of Ti-50.9at%Ni Alloy Processed by Equal Channel Angular Extrusion
Authors: Fan Zhi Guo , Xie Chao Ying
Published: March 2009

The initial coarse grains of Ti-50.9at%Ni alloy were refined into submicron grains, small
than 0.5 um in size, after eight passes Equal Channel Angular Extrusion (ECAE) at 500°C. Optical
microscopy and high temperature DSC tests were applied to investigate recrystallization behavior. It
is found that the recrystallization start (Rs) and recrystallization peak (Rp) temperatures of
Ti-50.9at%Ni specimens processed by eight passes ECAE are lower than that of the samples
processed by one pass ECAE. Ti-50.9at%Ni specimens processed by eight passes ECAE with
submicron grains are characterized by higher stability and need less energy to finish recrystallization
process.
Characterization of Mg-Al Sheet Clad Materials Fabricated by Hot Rolling
Authors: Lee Jae Seol , Son Hyeon Taek , Lee Ki Yong , Park Soon Sub , Kim Dae Guen , Bae Jung Chan
Published: March 2009

AZ31 Mg / 5083 Al clad sheet was fabricated by the hot rolling method and its
mechanical properties were investigated in this study. The tensile strength and yield strength of Mg-
Al clad samples were slightly higher than that of AZ31 Mg sample, resulting in high strength 5083
Al alloy. Also, in the case of the AZ31 Mg sample, tensile strength indicated different values to the
rolling directions. The thickness of interface layers between magnesium and aluminum materials
increased with increasing rolling temperature. The thickness of interface layer was about 1.2 μm
and 1.6 μm, respectively. The difference of thickness on the interface layer with variation of rolling
temperature was attributed to promote the diffusion between magnesium and aluminum materials.
The Vickers hardness of Mg-Al interface layer was around 125 Hv. The interface layer composed
of hard inter-metallic phases which may act a increment of Vickers hardness depending upon its
thickness.
Fluid-Structure Coupled Analyses of Composite Wind Turbine Blades
Authors: Cheng Tai Hong , Oh Il Kwon
Published: March 2009

The composite rotor blades have been widely used as an important part of the wind power
generation systems because the strength, stiffness, durability and vibration of composite materials are
all excellent. In composite laminated blades, the static and dynamic aeroelasticity tailoring can be
performed by controlling laminate angle or stacking sequence. In this paper, the fluid-structure
coupled analyses of 10kW wind turbine blades has been performed by means of the full coupling
between CFD and CSD based finite element methods. Fiber enforced composites fabricated with
three types of stacking sequences were also studied. First the centrifugal force was considered for the
nonlinear static analyses of the wind turbine so as to predict the deformation of tip point in the length
direction and maximum stress in the root of a wind turbine. And then, the aeroelastic static
deformation was taken into account with fluid-structure interaction analysis of the wind turbine. The
Arbitrary Lagrangian Eulerian Coordinate was used to compute fluid structure interaction analysis of
the wind turbine by using ADINA program. The displacement and stress increased apparently with
the increment of aerodynamic force, but under the condition of maximum rotation speed 140RPM of
the wind turbine, the displacement and stress were in the range of safety.
Mechanical Properties of Ultra-Fine Grained Fe-Cr-Ni Alloy Fabricated by ARB
Authors: Maekawa Taro , Kitahara Hiromoto , Tsuji Nobuhiro
Published: March 2009

Microstructures and mechanical properties of Fe-15wt.%Cr-10wt.%Ni alloy ARB
processed by various cycles were studied. The starting material showed lath martensite structure.
However, the austenitic phase became stable by the high straining (ARB) above Af temperature.
The volume fraction of austenitic phase greatly increased to around 90 % by 2 ARB cycles and
nearly saturated at about 95 % after higher ARB cycles. The grain refinement progressed during
the ARB, which leaded to the formation of ultrafine lamellar UFG austenitic microstructure with
mean lamellar spacing of about 300 nm. The UFG Fe-Cr-Ni alloy performed both high strength
and large elongation. Especially, the yield strength of the alloy ARB processed by 5 cycles
reached to 900 MPa, and the total elongation was 40 %. The good ductility of the present
specimens was attributed to the occurrence of transformation-induced plasticity (TRIP).
Influence of Annealing Atmosphere on the Mechanical and Wear Properties of Free-Cutting Phosphor Bronze Alloy
Authors: Cho Hoon , Lee Byoung Soo , Kim Hak Young , Jo Hyung Ho
Published: March 2009

The influence of annealing atmosphere on mechanical and wear properties of free-cutting
phosphor bronze alloy was investigated. After annealing in vacuum, the mechanical properties of the
alloy decreases due to vaporization of alloying element. In addition, the softening of matrix induces
decreasing the wear resistance dramatically. In contrast, high mechanical properties were observed in
the alloy annealed in air and in nitrogen atmosphere. In particular, a large smearing of lead in the alloy
annealed in air atmosphere was observed and was affected on the enhancement of wear resistance.
Consequently, annealing in vacuum atmosphere is not suitable for high mechanical properties and
wear resistance.
Optimization of Laser-Arc Interspacing Distance during CO2 Laser-GMA Hybrid Welding by Using High-Speed Imaging
Authors: Kim Cheol Hee , Chae Hyun Byung , Kim Jun Ki , Kim Jeong Han
Published: March 2009

Laser welding has not easily been adopted in shipbuilding industry because of its poor gap
bridging ability. Recently, laser-GMA hybrid welding process showed possibility to overcome the
tight gap tolerance with improved productivity. The laser-arc hybrid welding process is inherently
complex because it has three kinds of process parameters: arc welding, laser welding and hybrid
welding parameters. In this study, welding phenomena were investigated to optimize the hybrid
process parameter; interspacing distance between laser and arc. The bead surface and cross-sectional
shapes were evaluated, and weld pool shape and droplet transfer were monitored by high speed
camera to clarify welding phenomena.
Micro-Structural Evolution of AlCu5MnCdVA Cast Aluminum Alloy by Semi-Solid Isothermal Annealing Process
Authors: Yang Guang Yu , Jie Wan Qi , Hao Qi Tang , Zhang Run Qiang
Published: March 2009

Isothermal grain coarsening of AlCu5MnCdVA aluminum alloy prepared by permanent
mould casting during semi-solid treatment process was studied. It was found that the relationship
between the average diameter of α (Al) grains and the isothermal holding time fitted the formula
r − r = K ⋅ t
− −
'
3
0
3
, where the coarsening rate K’ varied with the holding temperature, which equaled to
4.288×10-10m3/s and 5.962×10-10m3/s at the holding temperature. A modified model of liquid film
migration has been proposed for explaining of 622°C and 631°C respectively the coarsening rate
variation with annealing temperature. The diffusion of the solutes as well as vacancies, and the grain
boundary tension are responsible for the microstructure evolution of AlCu5MnCdVA cast alloy.
Effects of the Process Parameters on Beads by Plasma Arc Welding of the Membrane for LNG Ships
Authors: Kim B.J. , Son Y.R. , Yun J.O. , Lee Jeong Soo
Published: March 2009

The membrane, which forms the primary barrier of the cargo tank onboard LNG carrier,
is made of corrugated sheets, angle pieces and sealing caps and so on. These components are
manufactured from SUS 304L sheets of 1.2mm thickness and assembled by the plasma welding.
There are several welding defects such as overlap, excessive convexity, excessive concavity of weld
and incomplete inclusion in the plasma welding. These unacceptable portions of the weld should be
removed and repaired in order to prevent propagation of the defects. So a study is undertaken to
determine the optimum process parameters such as the welding current, traveling speed, gas flow
rates and frequency in the plasma lap welding process for LNG ships in order to prevent these
defects. The polished and etched surface of the welded membrane sheet is examined if the cross
section shows a properly made weld. And the tensile tests are conducted to consider if the tensile
strength is less than the minimum required for the parent metal of the membrane sheet.
In Situ Combustion Synthesis of Ti-Al Intermetallic Compounds in Al Alloy Casting Process
Authors: Cho Gue Serb , Lee Kang Rae , Choe Kyeong Hwan , Lee Kyong Whoan
Published: March 2009

Ti-Al intermetallic compounds are regarded as promising materials for the hightemperature
structural and coating applications. We focused on the joining of Al casting alloy with
Ti-Al intermetallic compounds by in-situ combustion synthesis to improve the surface properties of
Al casting components. Microstructures and phase formation behavior of Ti-Al based intermetallic
compounds synthesized by combustion reaction were analyzed using scanning electron
microscope(SEM) equipped with energy dispersive x-ray spectroscopy (EDS) and x-ray
diffractometer(XRD) in Ti-Al intermetallic compounds. Three kinds of titanium aluminides of
Ti3Al, TiAl and TiAl3 were synthesized by the heat from the Al molten metal and a coating layer of
intermetallic phase were formed simultaneously on solidifed Al alloy surface. The shapes and
microstructures of reacted compacts were varied by mixing ratio of elemental powders. The TiAl3
intermetallic compound was observed in the compacts regardless of the mixing ratio of elemental
powders. And the unreacted Ti powders were remained in the reacted compacts due to the big size
of Ti powder and low exothermic heat of reaction between Ti and Al powders. The zone that poured
Al alloy diffused into the reacted Ti-25at.%Al compact of about 200 μm thickness was formed at
the interface by the reaction between liquid molten Al alloy and solid Ti powders in green compact.
Rheocast of Al-Si-Mg Alloy Containing 1Mass% Iron
Authors: Tsubata M. , Uetani Yasuhiro , Takagi Hidetoshi , Matsuda Kenji , Ikeno Susumu
Published: March 2009

In order to rheocast using Al-Si foundry alloy with higher concentration of iron,
semi-solid slurries were tried to manufacture by two different processes. The former process made
the slurry with granular solid phase and iron containing intermetallic compound β-phases of average
length of 60μm. In the latter process, morphology of the β-phases became thinner, although no
difference in their lengths. These slurries were rheocast to a disk shape with diameter of 80mm and
thickness of 5mm at slurry temperature of 873K. Ductility of the disk rheocast using the latter slurry
was slightly improved in comparison with that of the former slurry. However these levels of
ductility were still much lower than that of the slurry without β-phases.
Fatigue Crack Characteristics of Friction Stir Welded Aluminum Alloy Joints
Authors: Qu Hong Qiu , Tsujikawa Masato , Chung Sung Wook , Hirata Tomotaka , Oki Sachio , Higashi Kenji
Published: March 2009

Fatigue strength of Al5083-O FSW joints was evaluated in the relation of the FSW
conditions. Static strength of the joints in a range of FSW conditions was the same as that of base
metal. Because the fracture of the joints occurred at the base metal in the tensile tests. Therefore the
joint efficiency in tensile strength of joints with the FSW condition of tool rotation: 800 rpmwelding
speed: 100 mm/min (800-100), 800-200 and 500-100 are all hundred percent. However, the
fatigue strength of those joints with fine static strength varied very much. The joint efficiency for
fatigue strength varies from 75% for 500-100 to 31% for 800-200. Crack path in fatigue test was
always initiated at the center of back surface of FSW weld zone, and propagated through stir zone.
Crack growth rate measurement and fracture surface analysis resulted the difference of the joint
efficiency has a connection with the incomplete welding at back surface of joints.
Preparation of CaAl2O4: Eu2+ Long Persistent Blue Phosphor
Authors: Bartwal K.S. , Singh B.K. , Ryu H.
Published: March 2009

CaAl2O4:Eu2+ with high brightness and long persistent luminescence were prepared by solid state
reaction method. The phosphor compositions with varying Eu2+ were investigated by powder X-ray
diffractometer (XRD), SEM, TEM, photoluminescence excitation and emission spectra. Broad band UV
excited luminescence of the CaAl2O4:Eu2+ was observed in the blue region (λmax = 440 nm) due to transitions
from the 4f65d1 to the 4f7 configuration of the Eu2+ ion. The particle size also plays a role deciding the
luminescence characteristics of these phosphors. The decay time of the persistence indicated that the
persistent luminescence phosphor has bright phosphorescence and maintains a long duration.
Large Isothermal Magnetic Entropy Change after Hydrogen Absorption into La0.5Pr0.5(Fe0.88Si0.12)13
Authors: Fujieda S. , Fujita A. , Fukamichi Kazuaki
Published: March 2009

The influences of hydrogen absorption on the Curie temperature TC and the isothermal
magnetic entropy change for La0.5Pr0.5(Fe0.88Si0.12)13 have been investigated, because the
magnetocaloric effects have been confirmed to be enhanced after a partial substitution of Pr for La
in La(Fe0.88Si0.12)13. The value of TC for La0.5Pr0.5(Fe0.88Si0.12)13Hy increases from 185 to 324 K
with increasing y from 0 to 1.6. The maximum value of the isothermal magnetic entropy change
,Sm
MAX is slightly decreased by hydrogen absorption. However, ,Sm
MAX = -26 J/kg K in a
magnetic field change of 5 T for La0.5Pr0.5(Fe0.88Si0.12)13H1.6 is still larger than the value of -23 J / kg
K for La(Fe0.88Si0.12)13H1.5 having almost the same value of TC. Consequently, ,Sm
MAX of the
La0.5Pr0.5(Fe0.88Si0.12)13Hy is larger than that of La(Fe0.88Si0.12)13Hy in a wide temperature range
covering room temperature.
Structural Defects and Changes in Al-Pd-Fe Crystalline Approximant
Authors: Wang J.P. , Sun Wei , Zhang Z.
Published: March 2009

Crystalline approximants structurally related to decagonal quasicrystal in the as-cast and
heat-treated Al75Pd15Fe10 alloys and defect structures in them have been studied by means of
high-resolution electron microscopy (HREM). Structural defects of linear and planar types were
found to exist extensively in the orthorhombic ε16-phase formed in the as-cast Al75Pd15Fe10 alloy. In
contrast with the distribution and configuration of the defects in the as-cast ε16-phase, we found that
high-temperature heat treatment promotes the formation of a kind of regular network of structural
defects in the ε16-phase. This suggests that rearrangements of atom clusters and as well as defects
occurred due to the heat treatment. The relationship between the distribution of atom clusters and the
configuration of defects will be discussed.
Analysis on Void Closure Behavior during Hot Open Die Forging
Authors: Lee Young Seon , Kwon Y.C. , Kwon Yong Nam , Lee Jung Hwan , Lee S.W. , Kim N.S.
Published: March 2009

Internal voids have to be eliminated for defect-free in some open die forging. The FEM
analysis is performed to investigate the overlap defect of cast ingots during cogging stage. The
measured flow stress data were used to simulate the cogging process of cast ingot using the practical
material properties. Also the numerical analysis of void closure is performed by using the
DEFORMTM-3D. The calculated results of void closure behavior are compared with the measured
results before and after upsetting, which are scanned by the X-ray scanner. From this result, the
criteria for deformation amounts effect on the void closure were estimated into effective strain of 0.6
by the comparison of practical experiment and numerical analysis.
Structural and Mechanical Behaviors of Partially Devitrified Ti-Based Bulk Metallic Glass
Authors: Kang Chang Seog , Cho Jae Ik , Jeong C.Y. , Oh Ik Hyun , Lee Jae Seol , Park Joon Sik
Published: March 2009

The mechanical properties of the nano-size primary α-Ti phase in Ti55Zr18Ni6Cu7Be14
bulk metallic glass (BMG) have been examined through various annealing temperatures and times.
The yield strength and ductility were changed upon variation of α-Ti volume percent originate from
heating conditions. The strength mechanism and associated heating conditions (heating rate, time
and temperature) are discussed in terms of the microstructural observations and mechanical
properties.
Sound Radiation Characteristics for Structural Damage Identification
Authors: Lee Usik , Jang In Joon , Go Han Suk , Kim Tae Jin
Published: March 2009

This paper investigates the sound power radiated from a cracked plate. The sound power
is obtained by using a lumped parameters model-based acoustics theory and vibration responses
obtained by using the finite element method. It is shown that the vibration mode shapes and crack
angle are closely related to the sound radiation characteristics, which can be applied to detect
damages such as the cracks generated within a structure.
Synthesis Behavior of La0.7Ca0.3MnO3 by Hydrothermal Method
Authors: Im Hung Su , Lee Sang M. , Lee Chan Gyu , Koo Bon Heun , Yoon Jung Bum , Jung Myung Hwa
Published: March 2009

We indicated synthesization of LCMO by hydrothermal reaction. The results of
transmission electron microscopy revealed that the LCMO particles had wide range in size and
various in shapes. The LCMO particles had a perovskite-type crystal structure with some other
phases. Magnetic property was measured by physical property measurement system. Their
crystallinity and magnetization tended to increased with increasing reaction time.
Melting Liquid Joint Method of Ti(Cu)-Base Bulk Metallic Glassy Alloy
Authors: Son Kun Su , Wang Xin Min , Makino Akihiro , Inoue Akihisa
Published: March 2009

Techniques for joint of materials are developed over 2000 years. The metallic liquid jointing
technique which enables the joint of Ti41.5Cu42.5Ni7.5Hf5Zr2.5Si1 bulk glassy alloy without any
crystallization is very useful to produce large bulk metallic glass. High velocity molten alloy
streams are generated by ejection of alloy liquid through two nozzles at different sites. The jointed
region has nearly the same structure, thermal stability and mechanical properties as those for the
original glassy Ti41.5Cu42.5Ni7.5Hf5Zr2.5Si1 alloy.
Effects of Additional Elements on Structure, Mechanical Strength and Chemical Properties of Ni-Free Ti-Based Bulk Metallic Glasses for Biomaterials
Authors: Oak Jeong Jung , Kimura Hisamichi , Inoue Akihisa
Published: March 2009

We started investigation of new Ti-based bulk metallic glass (BMG) alloys with higher
glass forming ability (GFA) for dental implants for medical market. These Ti-based BMG alloys do
not contain Ni, Al and Be elements which are well known to be harmful for human body. In
particular, cylindrical rod specimens of newly designed Ti-based BMG alloys with produced by
copper mold casting exhibit compressive strength of above 1800 MPa. Ti-based BMG alloys also
have high corrosion resistance that is passivated at the lower passive current densities of
approximately 10-2Am-2 in 1 mass% lactic acid, 10-2~10-3Am-2 in PBS (-) at 310K which are lower
than those of pure Titanium and Ti-6Al-4V alloy. These BMG alloys have high potentials to be
applied as biomaterials in various forms, such as melt spun ribbons and cylindrical rods.
Configuration Optimization of Truss Structures Using Harmony Search Heuristic Algorithm
Authors: Lee Kang Seok , Song Jin Kyu
Published: March 2009

Most structural optimization methods are based on mathematical algorithms that require
substantial gradient information. The selection of the starting values is also important to ensure that
the algorithm converges to the global optimum. This paper describes a new structural configuration
optimization method based on the harmony search (HS) meta-heuristic algorithm. The HS algorithm
does not require initial values and uses a random search instead of a gradient search, so derivative
information is unnecessary. A benchmark truss example is presented to demonstrate the effectiveness
and robustness of the proposed approach compared to other optimization methods. Results reveal that
the proposed approach is capable of solving configuration optimization problems, and may yield
better solutions than those obtained using earlier methods.
Investigation of PTFE-Reinforced Integral Multi-Layered Self-Humidifying Membranes for PEM Fuel Cells Application
Authors: Zhang Yu , Zhang Hua Min
Published: March 2009

In this paper, novel durable self-humidifying membranes were investigated. It was shown
that the cell performance and the durability under dry operation condition have been improved.
Hydrogen Storage Properties of Mg-Al Alloy Prepared by Super Lamination Technique
Authors: Suganuma Kenta , Miyamura Hiroshi , Kikuchi Shiomi , Takeichi Nobuhiko , Tanaka Koji , Tanaka Hideaki , Kuriyama Nobuhiro , Ueda Tamotsu T. , Tsukahara Makoto
Published: March 2009

Microstructures and hydrogen storage properties of Mg-Al super laminate composite
alloys were investigated. The laminated sample was made by alternately stacking Mg films and Al
films. The laminate was subjected to repetition of stacking and cold-rolling under an ambient
condition (super lamination technique), combined with final heat treatment under an argon gas
atmosphere. The number of films and thickness was nearly 15000 layers and about 50μm,
respectivery. Their microstructures and hydrogen storage properties were studied by scanning
electron microscopy, X-ray diffractometry and volumetric method by use of a Sieverts-type
apparatus. In heat treatment process at 673K, Mg17Al12 intermetallic compound was formed by
interdiffusion. This compound absorbed and desorbed hydrogen reversibly through the
disproportionation and recombination react at 673K.
Nb-NbN Cermet Film as Solar Selective Coating
Authors: Wang Cong , Du Xin Kang , Wang Tian Min
Published: March 2009

A new cermet film Nb-NbN, deposited on the stainless steel substrate by direct reactive
magnetron sputtering, was reported as solar selective absorptive coating. Some fundamental studies
on microstructure and optical properties of the Nb-NbN cermet films were carried out by XRD,
EDX, SEM and spectrophotometer. A solar absorptivity of 0.94 and a normal emissivity of 0.16 at
room temperature were achieved for the coating. Thermal stability was investigated at 350°C and
500°C and it was observed that the absorptivity was changed in a range from 0.92 to 0.94 and the
surface emissivity varied firstly from 0.16 to 0.14 and then increasing to 0.19 when the temperature
was increased from room temperature to 350°C and up to 500°C.
Enhanced Formability of AZ31 Magnesium Alloy Sheet Processed by Equal Channel Angular Rolling and Annealing Treatment
Authors: Chen Zhen Hua , Cheng Yong Qi , Xia Wei Jun , Yan Hong Ge , Chen Ding
Published: March 2009

In order to improve the formability of AZ31 magnesium alloy sheet at room temperature,
a new process, so-called equal channel angular rolling (ECAR) and followed by annealing treatment
was applied to process the sheet. The optical microstructure of the as-received sheet was similar with
that of the ECARed one after annealing treatment, the Erichsen value and limiting drawing ratio of the
ECARed sheet was about 6.26mm and 1.6, respectively, which was much larger than that of 4.18mm
and 1.2 for the as-received sheet. These can be attributed to the low yield ratio and high strain
hardening exponent due to the modified texture induced by the shear deformation during ECAR
process, which is favor of the activations of basal slipping and twinning at ambient temperature,
especially deforming at the rolling direction.
Fabrication of Monolithic UAl2 Pellet for High-Density Nuclear Fuel
Authors: Kim Ki Hwan , Park Jong Man , Lee Don Bae , Chi Chul Goo , Kim Chang Kyu
Published: March 2009

Uranium powder, which can be obtained by the atomization process, was used to fabricate
UAl2 by using powder metallurgy technology. Uranium powder and Al powder were blended,
extruded, and annealed into a UAl2 rod in a mold. Sound UAl2 rods were fabricated by the powder
metallurgical process. The relative density of the UAl2 pellet formed by an annealing was at about
94%. The density increased with higher constraints on the mold and a smaller particle size of the
uranium powder. A coarse uranium powder of about 80 μm in average diameter represented the
remaining un-reacted uranium phase. On the other hand, a fine uranium powder of about 50 μm in
average diameter could achieve a pure UAl2 phase without a uranium phase. The analysis by an X-ray
diffraction pattern confirmed that the annealed specimens had interacted to form a UAl2 phase.
Conclusively, the sintered UAl2 pellet is expected to be useful in developing advanced fuels.
Microstructural Evolution in Cerium Dioxide Irradiated with Heavy Ions at High Temperature
Authors: Mihara Takeshi , Abe Hiroaki , Iwai Takeo , Sonoda Takeshi , Wakai Eiichi
Published: March 2009

Cerium dioxide (CeO2) is a well-studied oxide because of its technological applications,
such as a major component in the catalysts, stable capacitors and so on. CeO2 with a cubic fluorite
structure is also expected as the material for simulating behaviors of uranium dioxide under energetic
particle irradiation, which leads high burn-up structure attributable to pressure increase in fuel
cladding tubes. In this work, the stability of crystal structure and surface morphology change in CeO2
will be clarified. Polycrystalline samples were irradiated with 300 keV Xe+, 18 MeV I5+, 350 keV O+
and 12 MeV O3+ ions at temperatures from 370 to 1000 K. Microstructural evolutions was
investigated with Scanning electron microscopy, Raman Spectroscopy and X-ray diffractometry.
Irradiation effects at high temperature were observed as surface etching and resulting bubble
formation, however blistering was not detected. Raman spectra and diffraction data indicates
diffusion of oxygen vacancies is sufficient at 900 K and above.
Optimization of Preform in Forging Process Using Kriging Model
Authors: Oh Seung Hwan , Park Joon Hong , Lee Kwon Hee , Kang Dong Hun , Song Xue Guan , Kang Jung Ho , Park Young Chul
Published: March 2009

The welding process, a conventional production method of gate valves, has advantages
such as light weight, but it also has disadvantages such high production price. However, the forging
process, has economic merits and mass production capability. The main focus of this paper is the
optimization of the preform in the forging process. This paper proposes an optimal design of the
preform to improve the mechanical efficiency of the gate valve made by the forging method. The
design of the preform is optimized by the use of the real response model to the Kriging model by
computer simulation. Also, the optimized results were used to verify the response model. The
verified response model confirmed the usefulness and reliability of the Kriging method in optimum
structural design of preform achieved by finite element analysis and Kriging equations.
Springback Compensation Based on Finite Element for Multi-Point Forming in Shipbuilding
Authors: Lee Jang Hyun , Yoon Jong Sung , Ryu Cheol Ho , Kim Sang Hyun
Published: March 2009

Flame bending has been widely used for forming hull plates of marine vessels, Since it is
difficult to estimated the amount of residual deformation after applying the flame heat, flame bending
has been carried out by skilled workers without automatic facility. A mechanical bending such as
multiple-piston pressing forming has been studied as an alternative to the flame bending. However,
springback is a major problem in the press forming process. Present paper presents a combination of
FEM (Finite Element Method) and springback compensation algorithm to calculate the compensated
stroke of pressing points. In order to calculate the springback, the process is modeled by an elastic
plastic material and shell elements. Combination of global scale factor and local scale factors is
suggested to adjust the amount of strokes through an iterated numerical calculation. In each iteration,
shape deviation between object surface and processed shape is minimized to reach the designed
shape. The shape deviations due to springback are compensated using the residual shape estimated by
FEM.
Enhancing Fatigue Properties of Nanostructured Metals and Alloys
Authors: Lowe Terry C.
Published: March 2009

Recent research on the fatigue properties of nanostructured metals and alloys has shown
that they generally possess superior high cycle fatigue performance due largely to improved
resistance to crack initiation. However, this advantage is not consistent for all nanostructured
metals, nor does it extend to low cycle fatigue. Since nanostructures are designed and controlled at
the approximately the same size scale as the defects that influence crack initiation attention to preexisting
nanoscale defects is critical for enhancing fatigue life. This paper builds on the state of
knowledge of fatigue in nanostructured metals and proposes an approach to understand and improve
fatigue life using existing experimental and computational methods for nanostructure design.
Microstructure and Morphology of Alumina-Iron Nanocomposite Powders Produced by High Energy Mechanical Milling
Authors: Yusop M. , Zhang De Liang , Wilson M.
Published: March 2009

Alumina-iron nanocomposite powders containing 5vol.% of iron were fabricated by
high-energy ball milling with different ball-to-powder weight ratios (BPRs) as part of the study of
ceramic-metal nanocomposite magnetic materials. The microstructure and morphology of the
composite powders were characterized using the X-ray diffraction, optical microscopy and scanning
electron microscopy. XRD analysis and SEM examination in combination with energy dispersive
X-ray spectrometry confirmed that the nanocomposite structure of the powder particles formed only
after 8 hours milling for both BPRs used. With a higher BPR of 16:1, Fe-Cr alloy material was
broken from the stainless steel balls and incorporated into the nanocomposite powder. However,
such a problem did not occur with a lower BPR of 5:1. The mechanism for formation of the alumina
matrix nanocomposite powder is found to be dependent on BPR and milling time.