bluuebunny/crossref_metadata_2025 huggingface dataset:
α Phase Forming on Surface Layer and Precipitating inside of a Ti-Mo Based Alloy Annealed in Air
Authors: Song Jie , Xie Chao Ying
Published: March 2009

α-phase forming on the surface layer and precipitation of α-phase inside a Ti-Mo alloy
during annealing in air has been investigated thermodynamically. α-phase layer is increased rapidly
when annealing temperature exceeds 700°C. When the 850°C solution-treated specimen annealed at
400°C for 1 hour, there is no α-phase precipitates. As annealing temperature increased to 800°C, the
amount of α-phase precipitates first increased to a maximum at 600°C, then decreased.
The Effects of Si on the Nucleation Kinetics of Ferrite in Dual Phase Steels
Authors: Lee Sang Hwan , Lee Kyung Jong
Published: March 2009

It is generally accepted that Si promotes kinetics of polygonal ferrite due to
thermodynamic factors such as Ae3 and maximum amount of ferrite formed. However, in this study, it
was found that the difference between the measured rates of ferrite formation in C-Mn steel and Si
added steel was much larger than that expected considering only thermodynamic factors. The
classical nucleation theory with pillbox model was adopted to figure out what is the most controlling
factor in formation of ferrite. The volume free energy change was calculated by use of the dilute
solution model. The diffusivity of carbon (DC) was formulated as functions of C, Mn and Si by using
experimental data. It was found that the volume free energy change was still predominant but the
kinetic factors such as interfacial energy and the diffusivity of carbon by addition of Si were not
negligible at lower undercooling. However, with increasing undercooling, the diffusivity of C was
the most effective on the ferrite kinetics, though the ambiguity of treating interfacial energy was not
yet clear.
Friction Behavior of HVOF Thermal Spray Coating of Micron Size WC-Co Powder
Authors: Cho Tong Yul , Yoon Jae Hong , Kim Kil Su , Song Ki Oh , Joo Yun Kon , Fang W. , Zhang Shi Hong , Youn Suk Jo , Chun Hui Gon , Hwang Soon Young
Published: March 2009

High velocity oxy-fuel (HVOF) spray coating of WC base cermet has been studied as a
promising candidate in some hard coating area for a replacement of the long traditional electrolytic
hard chrome (EHC) plating, which has been raising public health and environmental problems.
Micron size WC-Co (mWC-Co) has been coated on Inconel 718 substrate by HVOF thermal spray
coating process. Surface properties of coating layer and friction behavior have been investigated for
durability improvement coating on the sliding machine component surface.
First Principles Study on the Adsorption of Alkali Metal on C(100)( 2×1)
Authors: Nie J.L. , Xiao Haiyan , Zu Xiao Tao , Gao Fei
Published: March 2009

First-principles calculations based on density functional theory, using PW91 functional
have been performed to study the adsorption of Alkali metal (AM) on C(100)(2×1) surface. The stable
geometries, adsorption energies for all adsorption configurations have been calculated on half a
monolayer and one monolayer. The preferred binding sites have been determined to be valley-bridge
sites at the coverage of 0.5ML. At higher coverage of 1ML, two AM adsorbates were found to reside
in pedestal site and valley-bridge site, respectively. Work function analysis showed that when AMs
are adsorbed on C(100)(2×1) surface, the work function decreases linearly with increasing coverage
and reaches a minimum at Θ=0.5ML. At higher coverage, the work function is increased again, which
may be caused by depolarization effect of the adsorbate.
Study on the Properties of Chromium Matrix Composite Plated with Nanosized Diamond Powders
Authors: Nguyen Viet Hue , Hoang Thi Nam , Kwon Sik Chol , Kim Man , Lee Joo Yul
Published: March 2009

A study on chromium matrix composite plated with nanosized diamond powders was
undertaken by employing a standard Sargent bath. Chromium matrix composite plated with
nanosized diamond powders manifested super properties. The microhardness was varied from 890
to 920 HV (load 25 g/f), as compared with 801 HV of pure chromium; the wear resistance was
increased 3-4 times. The potentiodynamic measurement in a chloride medium showed that the
passive current of chromium matrix composite plated with nanosized diamond powder was 6 times
as lower as that of pure chromium. Microscopic observation indicated that nano-diamond powders
were included in the chromium deposit in the form of single and multi crystalline.
Heat Resistance of Mg-Nd Based Casting Alloys Containing Gadolinium and Yttrium
Authors: Jun Joong Hwan , Park Bong Koo , Kim Jeong Min , Kim Ki Tae
Published: March 2009

Influences of Gd or Y addition on microstructures and tensile properties at room and elevated
temperatures were investigated for T6-treated Mg-3%Nd-0.5%Zn-0.4%Zr casting alloys, on the basis of
experimental results from X-ray diffractometry, scanning electron microscopy, transmission electron
microscopy, energy dispersive spectroscopy, tensile and creep tests. Microstructures of the T6-treated
alloys are characterized by recrystallized α-(Mg) grains containing various nano-sized precipitates such
as Mg41Nd5, Zn2Zr3 and Zr particles. In T6 condition, most of added Gd and Y elements are dissolved
in Mg41Nd5 precipitates rather than formation of new phases. Tensile properties and creep resistance
of the Mg-3%Nd-0.5%Zn-0.4%Zr alloy are remarkably increased by the addition of Gd or Y, but their
efficiencies are substantially the same.
Mechanical Properties of Twin Roll Cast AZ91 Magnesium Alloy at Room Temperature
Authors: Uchida Shu Hei , Takeuchi Ippei , Gonda Gentaro , Hirai Kinji , Uesugi Tokuteru , Takigawa Yorinobu , Higashi Kenji
Published: March 2009

Twin roll casting process combines casting and hot rolling into a single process. In this study,
mechanical properties at room temperature and microstructure of the twin roll cast AZ91
magnesium alloy are investigated. The alloy exhibited a good combination of high ultimate strength
of 343MPa, yield stress of 224MPa and elongation to failure of 13%. The mechanical property was
very excellent compared with AZ91 die-cast alloy. EPMA analysis reveals that the Al concentration
in Mg matrix is higher in twin roll cast alloy than that in die-cast alloy. This high Al concentration
must be the origin of the good mechanical properties of twin roll cast alloy at room temperature.
Metal Injection Molding of Nickel-Free Austenitic Stainless-Steels I-Manufacturing Process
Authors: Kuroda Yoshikazu , Komada Midori , Murakami Ryo , Fukumoto Shingo , Tsuchida Noriyuki , Harada Yasunori , Fukaura Kenzo
Published: March 2009

Ni-free austenitic steels containing high nitrogen have been developed to protect
against earth resource. High nitrogen steels (HNS) have a lot of advantages, e.g., HNS have high
strength, corrosion resistance, toughness, work hardening rate and large rocking parameter in the
Hall-Petch equation. On the other hand, it is difficult to fabricate HNS by IM method under 0.1
MPa and to work at room temperature. We have tried to make HNS by combined use of metal
injection molding method (MIM) and nitrogen absorption method. Powder compositions used was
Fe-17Cr-12Mn-3Mo.The benefit of this method is to make metal parts in near net shape. In order to
use this method, we should know the sintering heat schedule, timing for introducing nitrogen gas,
gas pressure and setter material etc. Therefore, the shrinkage rate, density and the solution-treated
microstructure of MIM compacts were examined to find out the optimum conditions.
Microstructure and Dynamic Ultra-Micro Hardness of the As-Cast and Extruded Mg-Al-Ca-Sm Alloys
Authors: Son Hyeon Taek , Lee Jae Seol , Hong Ji Min , Kim Dae Guen , Yoshimi Kyosuke , Maruyama Kouichi
Published: March 2009

The as-cast microstructure of Mg-5Al-3Ca-2Sm alloy consists of equiaxed α-Mg matrix,
(Mg, Al)2Ca eutectic phase and Al-Sm rich intermetallic compounds. This eutectic phase of the
extruded alloys was elongated to extrusion direction and size of this phase was finered compare to
that of as-cast alloys because of severe deformation during hot extrusion. After hot extrusion, the
average grain size of Mg-5Al-3Ca and Mg-5Al-3Ca-2Sm alloys was 4.8 *m and 3.8 *m, respectively.
In load-unload hardness test, penetration depth was decreased with added Sm and after extrusion
procedure because of grain size refining by addition Sm and large deformation. Hardness value of the
alloys containing Sm was higher than that of Mg-5Al-3Ca alloy due to grain refining and formation
Al-Sm rich intermetallic compound at gain boundary and α-Mg matrix. Maximum hardness value
was obtained at the extruded Mg-5Al-3Ca-2Sm alloy at elevated temperatures.
Continuous Rheological Forming of A6061 Wrought Aluminum Alloy by Using Helical Shape Stirrer and its Thixoforging Process
Authors: Kang Chung Gil , Lee Sang Mae
Published: March 2009

Interest in the rheology forming technology for fabrication of light weight materials and for
resolving environmental issues has been growing in industrial and academic society. In this study,
the helical shape stirrer was designed to produce rheological material. The experimental variables,
which were stirring time 0-1200 sec, stirring velocity 0-100 rpm and melt temperatures for semisolid
states, were established. The rheological materials were produced under established
experiment conditions, and then mechanical properties were measured. Sequence-production
equipments were appended to fabrication system of rheology material to make rheology materials
continuously. Therefore, the development of sequence-production system equipped with a specially
designed mechanical stirrer in spiral shape was necessary for fabricating fine grains and their
uniform globular rheology materials. The thixoforging was experimented with rheological A6061
wrought aluminum alloy fabricated by the spiral shape stirrer. Microstructural morphology of the
forged samples was investigated and their mechanical properties characterized.
Influence of Microstructure Change on the Superplastic Properties of Ti3Al Base Alloy
Authors: Liu Ying Ying , Yao Ze Kun , Luo Xi , Cao Li Kun
Published: March 2009

The superplastic properties of Ti3Al base alloy have been investigated in the range of
900~1020°C and strain rate range of 3.3×10-4~3.3×10-2s-1 .The largest elongation of 1570% was
obtained under the optimal superplastic deformation condition of 980°C and 3.3×10-4 s-1. The
m-value varied from 0.46 to 0.59, its maximum value was obtained at 980°C.The microstructure of
the alloy after heat treatment was composed of two phases of small spherical α2 phase particles
distributing in βtransus matrix. Microstructure change has an obvious effect on the superplastic
properties of Ti3Al-based alloy. At 980°C,when theα2 phase grain size changed from large to small
then large and the cavitations in the fracture surface were larger and deeper with decreasing strain
rate, the alloy showed the larger elongation and the lower flow stress.
Effect of Heat Treatment Conditions on Microstructure and Fracture Toughness of a Cast Ti-Al Alloy
Authors: Ha Tae Kwon , Jung Jae Young
Published: March 2009

Ti-45.5Al-2Cr-4Nb-0.4B alloy was cast by vacuum arc melting at high purity Ar
atmosphere using high purity sponge Ti, granular Al (99.99%), flake Nb (99.9%), lump Cr (99.9%)
and TiB2 (99.5%) and subsequently heat-treated to obtain a couple of microstructures, i.e. lamellar
and near γ. The heat treatment consisted of annealing at a high temperature (1200 ~ 1330oC) of
different phase fields for 24 hrs and stabilizing at 900oC for 4 hrs followed by air cooling. Fracture
toughness was measured on the specimens with different microstructures at room temperature. The
value of KQ of specimen with fully lamella structure was obtained as 18.68 MPa √m, much higher
than that of specimen with near γ structure (11.84 MPa √m). It was also revealed that the KQ value was
decreased as the annealing temperature decreased.
Metal Injection Molding Method of Ni-Free Austenitic Stainless Steel II - Microstructure and Mechanical Properties
Authors: Komada Midori , Kuroda Yoshikazu , Murakami Ryo , Tsuchida Noriyuki , Harada Yasunori , Fukaura Kenzo , Fukumoto Shingo
Published: March 2009

Microstructure and mechanical properties of high nitrogen steels whose chemical
composition were Fe-17Cr-12Mn-3Mo and that was produced by using metal injection molding
method and nitrogen absorption methods were examined. A compact which is furnace cooled from
1573 K has a brittle surface layer with high chromium and nitrogen contents but the surface layer
disappears when the compact is held at 1473 K. The compact which is furnace cooled at 1473 K is
observed precipitates in the grains and the grain boundary, while the compact which is quenched at
1473 K shows homogeneous microstructure. In the heat treatments at 1473 K for 2, 5, and 10 h, the
nitrogen content becomes higher with increasing of holding time. In the holding times of 5 and 10 h,
the microstructure is austenite. In the tensile tests, tensile strength becomes larger with increasing of
nitrogen content. In the specimen which is conducted the heat treatment at 1473 K for 10 h, tensile
strength is about 1,000 MPa and elongation is 80 %, which shows better balance of strength and
elongation than SUS304 and SUS316 steels.
Interfacial Characteristics of Iron Aluminides Intermetallic Layers on Al-Coated Steel Sheet
Authors: Rahmawan Yudi , Baek Eung Ryul , Kim T.H.
Published: March 2009

The characteristics of Al-coating materials on low carbon steel sheets during high
temperature oxidation process were investigated. The phases’ evolution and growth were
systematically evaluated by SEM/EDS and XRD. The hardness distribution from the surface to the
steel substrate was measured to check the brittleness of iron aluminides coating layers. The
oxidation properties of coating materials were investigated using weight gain method. Intermetallic
compound recognized as FeAl3 was initially formed on the interface between steel substrate and
coating materials. After exposing the specimens at elevated temperature, FeAl3 layer was gradually
transformed into Fe2Al5, FeAl2, and FeAl+Fe3Al. Oxidation rate increased fastly after α-Al in the
coating completely transformed at 650 °C. The brittle FeAl3 and Fe2Al5 have the lower resistance to
oxidation because the easier cracking during intermetallic reaction.
Effect of Creep Deformation on the Crystallographic Orientation Distribution in Ni Base Superalloy
Authors: Inoue Toru , Tanaka Katsushi , Adachi Hiroki , Kishida Kyosuke , Inui Haruyuki
Published: March 2009

The crystallographic orientation distribution, and its change as a function of creep
deformation in Ni-based single crystal superalloys have been investigated by X-ray diffractometry.
The distribution of the crystallographic orientation has significantly broadened by creep
deformations. Directional broadening of the distribution agrees with creep dislocations having the
burgers vector of 1/2<101>. High temperature creep strain of superalloys can be estimated by a
non-destractive test where the width of rocking curve of a diffraction peak is measured.
Study on the Properties of Doped La in BaBi4Ti4O15 Ceramic
Authors: Yang Xing Hua , Huang Jin Liang , Wang Xiao , Cui Chun Wei
Published: March 2009

BaBi4-xLaxTi4O15 (BBLT) ceramics were prepared by conventional solid phase sintering
ceramics processing technology. The crystal structure and the microstructure were detected by X-ray
diffraction (XRD) and scanning electron microscope (SEM). The XRD analyses show that La3+ ions
doping did not change the crystal structure of BBT ceramics. The sintering temperature increased
from 1120°C to 1150°C with increasing Lanthanum content from 0 to 0.5, but it widened the sintering
temperature range from 20°C to 50°C and refined the grain size of the BBT ceramic. Additionally,
polarization treatment was performed and finally piezoelectric property was measured. As a result,
the piezoelectric constant d33 of the 0.1at.% doped BBLT ceramics reached its highest value about
22pc/N at polarizing electric field of 8kV/mm and polarizing temperature of 120°C for 30min.
Preparations and Characterizations of Perovskite PMN Ceramics by Using a One-Step Calcination Method
Authors: Chen Jin , Fan Hui Qing , Chen Xiu Li , Qiu Shao Jun
Published: March 2009

A relaxor ferroelectric material, Pb(Mg1/3Nb2/3)O3 (PMN) powder with a pyrochlore-free
phase, was prepared by using a one-step calcinations method. The pyrochlore phase was prevented by
coating Mg(OH)2 on Nb2O5 particles. Pure-perovskite PMN powder was synthesized by a single
calcination of the coating powder mixed with appropriate amounts of PbO at 900 oC for 2 h. The
pyrochlore-free perovskite PMN powders were sintered to 96.9% density at 1100 oC. The sintered
PMN ceramics exhibited a dielectric constant maximum of ~11 700 at room temperature at a
frequency of 1 kHz.
Electrochemical Properties of Cathode for Solid Oxide Fuel Cell with Gd-Doped Ceria Electrolyte
Authors: Shimonosono Taro , Hiramatsu Go , Hirata Yoshihiro , Sameshima Soichiro , Matsunaga Naoki , Doi Toshiya , Horita Teruhisa
Published: March 2009

Electrochemical properties (terminal voltage, ohmic resistance and overpotential) were
measured for the cells of indium tin oxide (ITO, 90 mass% In2O3-10 mass% SnO2), perovskite-type
oxide La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) or SrRuO3 cathode / Gd-doped ceria electrolyte (Ce0.8Gd0.2O1.9,
GDC, 600-700 μm thick) / Ni-GDC anode using 3 vol% H2O-containing H2 fuel at 873 and 1073 K.
The highest power density was obtained for the cell with SrRuO3 cathode, and was 36 and 328
mW/cm2 at 873 and 1073 K, respectively. The voltage drop was larger for the cathode than for the
anode. Both of the ohmic resistance and overpotential were lowest for the SrRuO3 cathode among
the investigated cathodes.
Fabrication of Porous Alumina Ceramics by Spark Plasma Sintering Method
Authors: Choi Dae Ho , Kamada Kai , Enomoto Naoya , Hojo Junichi , Lee Soo Wohn
Published: March 2009

In this work, porous alumina ceramics were obtained by controlled sintering
of alumina-carbon black powder mixtures. In order to develop the porous alumina
ceramics with high strength, as the amount of carbon black increased, the number of
small pores increased because the pore characteristics and relative density the influence
of SPS condition and carbon black content on was studied.
Dynamic Thermo-Mechanical Properties of Chemically Surface Modified MWCNTs Reinforced Polymeric Composites
Authors: Sulong Abu Bakar , Park Joo Hyuk
Published: March 2009

The dynamic thermo-mechanical properties of two types of chemically surface modified
(Carboxylated and Octadecylated) multi-walled carbon nanotubes (MWCNTs) and As produced
MWCNTs reinforced epoxy matrix composites are investigated by Dynamic Mechanical Thermal
Analyzer at 1.0 wt% concentration. Moreover, influence of MWCNTs concentration variations to
the dynamic thermo-mechanical properties are evaluated at Carboxylated MWCNT reinforced
polymeric composites (from 0.1 to 5.0 wt %). Higher interfacial bonding strength is achieved by
introducing the chemical surface modification. Also MWCNTs reinforced polymer shows higher
storage modulus (from 30°C to 70°C) than pure polymer. Moreover, the storage modulus of
composites increases linearly by increasing MWCNTs concentration. However, glass transition
temperature (Tg) of composites decreases linearly by increasing MWCNTs concentration.
Sticking Mechanisms Occurring during Hot Rolling of Ferritic Stainless Steels
Authors: Lee Jong Seog , Son Chang Young , Kim Chang Kyu , Ha Dae Jin , Lee Sung Hak , Kim Kwang Tae , Lee Yong Deuk
Published: March 2009

Sticking phenomenon occurring during hot rolling of ferritic stainless steels, STS 430J1L
and STS 436L, was investigated in this study. The simulation test results at 900 oC and 1000 oC
revealed that STS 430J1L had a smaller number of sticking nucleation sites than the STS 436L.
When the test temperature was 1070 oC, the sticking hardly occurred in both stainless steels as Fe-
Cr oxide layers were formed on the surface of the rolled materials. These findings suggested that
the improvement of high-temperature properties of stainless steels and the appropriate rolling
conditions for readily forming oxide layers on the rolled material surface were required in order to
prevent or minimize the sticking.
Properties of CB/Rubber Composites Filled by Carbon Black Used as Catalysts for Hydrocarbon Decomposition
Authors: Dai Shuang Ye , Ao Ge You , Kim Myung Soo
Published: March 2009

Carbon blacks were used as catalysts for hydrogen production through hydrocarbon
decomposition. The aim of this work is to find suitable conditions for decomposition reaction to cut
down the net cost of hydrogen production. Carbon blacks after hydrocarbon decomposition under
different operation conditions were mixed with NBR rubber. The surface area of carbon black
increased with low weight gain in methane decomposition caused by carbon deposits on the surface of
carbon black aggregates, and the decrease of surface area with further weight gain might be due to the
carbon deposits adhering to each other and forming bigger aggregates. The same results were gotten
from decomposition of mixture gas of methane and propane. The surface area of carbon black always
decreased with the development of propane decomposition reaction. With the same carbon black
loading, the composites filled by carbon blacks with low weight gain in methane and
methane-propane mixture gas decompositions showed higher tensile strength than those mixed with
raw carbon blacks, but there were no significant differences in 300% modulus. With the increase of
carbon blacks loading in all composites, 300% modulus and tensile strength always increased. The
surface resistivity of composites showed that it was much easier for carbon blacks with low weight
gain in methane and methane-propane mixture gas decompositions to dissipate well in the in rubber
system.
Electromagnetic Interference Shielding Properties of Carbon Nanotubes Reinforced Composites
Authors: Kim Tae Wan , Lee Hye Rim , Kim Sung Soo , Lim Yun Soo
Published: March 2009

Electromagnetic interference (EMI) shielding refers to the reflection and/or adsorption of
electromagnetic radiation by materials, which acts as a shield against the penetration of the
radiation through the shield. In this study, two directional carbon fibers reinforced composites
with carbon nanotubes as fillers were studied for the high frequency electromagnetic properties and
mechanical properties. Carbon nanotubes were prepared by a catalytic chemical vapor deposition
method with ferrocene/xylene mixture. The electromagnetic insulating properties were measured
by micro strip line method in this study. Electromagnetic interference shielding properties of
composites were investigated in the frequency region of 0.3-6 GHz. The experimental results
indicated that the EMI shielding effectiveness of carbon composite is sensitive to the existence of
CNT.
Effect of Powder Blending Ratio on Synthesis of TiB2 Particles by Al-Ti-B Combustion Reaction
Authors: Yoshida Wataru , Kobashi Makoto , Kanetake Naoyuki
Published: March 2009

It is favorable to disperse fine strengthening particles under 1μm to expect the
effective dispersion strengthening mechanism of metal matrix composites. In this research, TiB2
particle was synthesized in Al matrix by a combustion reaction and the influence of the powder
blending ratio was examined in detail. The mole mixture ratio of Ti and B powder was fixed to
B/Ti=2, and the blending ratio of Al powder was varied from 40 to 70vol%. The compacted
blended powder was heated under an Ar atmosphere in an induction furnace, and heating was
stopped immediately after the combustion reaction took place. The synthesized TiB2 particle
became finer by increasing the blending ratio of Al, and the dispersion of particles about 0.3μm was
achieved. However, large quantity of Al-Ti intermetallic compounds remained when 70vol% Al
was blended, indicating that the combustion reaction was not completed in this specimen.
Effect of Phosphorus Doping into the Silicon as an Anode Material for Lithium Secondary Batteries
Authors: Kong Myung Ho , Byun Dong Jin , Lee Joong Kee
Published: March 2009

Carbonaceous material has been used as an anode in lithium-ion secondary batteries due to
their good stability during charging and discharging. But this material has the problems like
irreversible capacity and low specific capacity that is about 372mAh/g. Because of the problems as
stated above, silicon-based materials have been reported as possible anode materials to replace
carbon. But they have high electrical resistivity and large volume changes associated with alloying
and dealloying of lithium during electrochemical cycling. This study is performed to obtain higher
capacity of anode material with a good cycle performance and to reduce electrical resistivity. It is
expected that phosphor doping silicon and graphite mixture exhibit higher capacity than that of raw
graphite and the doping of phosphorous will be able to decrease electrical resistivity of anode
materials.
Dry Sliding Wear Mechanisms of the High Nitrogen Austenitic 18Cr-18Mn-2Mo-0.9N Steel at Different Applied Loads
Authors: Kim Yong Suk , Kim Seung Duk , Kim Sung Joon
Published: March 2009

Sliding wear mechanisms of the solution treated 18Cr-18Mn-2Mo-0.9N high nitrogen
steel (HNS) were studied. Room-temperature dry sliding wear tests of the steel were carried out at
various applied loads to explore the mechanism as a function of the load. The wear rate of the steel
increased with the increase of the load; however, the increase rate was not constant. The rate
increased slowly at low loads, rapidly at intermediate loads, and finally, the increase-rate became
low again at high loads. Worn surfaces, their cross sections, and wear debris were examined, and
phases of the heat-treated HNS as well as the wear debris were identified to find out the mechanism.
The wear of the steel was found to be controlled by the tribo-oxidation, strain-induced phase
transformation, and reverse transformation due to temperature rise on a wearing surface. The
influence of each mechanism on the rate varied depending on the magnitude of the applied load.
Temperature Dependent Microstructure and Mechanical Behavior in AZ31 Alloy Processed by an Asymmetric Rolling
Authors: Jeong Ha Guk , Kim Woo Jin
Published: March 2009

An asymmetrical rolling of AZ31 alloy sheets was carried out at 473 K with a high
reduction ratio of 70% in thickness prior to tensile-tests. For the as-rolled sheet, tensile tests were
performed in a temperature range of 473 ~ 673 K at a constant strain rate of 1 × 10-3 s-1. Tensile
elongation increases with increasing reduction ratio in the as-rolled sheets. A large elongation of above
530% was obtained in the specimen deformed at 673 K for the sheet fabricated by 70% thickness
reduction. Although the extent of grain growth was remarkable in a high temperature range, the tensile
elongation increases with increasing the tensile temperature.
Research on Horizontal Electromagnetic Continuous Casting of Sn-P Bronze Strips
Authors: Hui Chun Hua , Li Ting Ju , Jin Wen Zhong
Published: March 2009

In order to improve the quality of tin-phosphor bronze strips, the horizontal
electromagnetic continuous casting technology, i.e. imposing alternating electromagnetic field to the
horizontal continuous casting process of tin-phosphor bronze strips was developed. The effect of
electromagnetic field on the quality of tin-phosphor bronze strips was studied with electron probe
microanalysis (EPMA) and optical microscope. The results showed that when the alternating
electromagnetic field with 50 Hz frequency and 18 A current was imposed, the crystal grain of the
tin-phosphor bronze strips was obviously refined and the segregation and shrinkage cavity were
greatly reduced. The quality of tin-phosphor bronze strips was remarkably improved, so the annealing
time was shortened from 7 hours to 5 hours, and the service life of graphite mold was extended from
168 hours to 334 hours.
Experimental Study of Springback in Draw Bend Test of AZ31B Magnesium Alloy Sheet
Authors: Lee M.G. , Choi J.G. , Kim Heon Young , Wagoner R.H. , Lee June Key
Published: March 2009

Springback has been measured under various process conditions corresponding to those
found in real press-stamping operations. The draw bend tests originally developed at Ohio State
University (Carden et al., 2002 [1]) were conducted using a range of tool radii, direct controlled
constraining forces, and friction conditions. Especially, the draw-bend test was able to apply precise
constant restraining force and almost negligible friction by rotating the cylindrical tool with the same
speed of drawn sheet strip. Springback angle changes were measured for the bending and sidewall
curl regions to find the dependence on the process variables. As expected, tensile restraining force
dominates the springback sensitivity, with higher forces reducing springback. The measured
springback angles and curvatures were reported for use in modeling of springback of higly
anisotropic and asymmetric magnesium alloy sheets.
Formability and Mechanical Property of Aluminum Sheets Locally Surface-Modified by the Concept of Surface Friction Joining
Authors: Lee Chang Gil , Kim Sung Joon , Han Heung Nam , Chung Kwan Soo
Published: March 2009

Formability and mechanical property of Al sheets whose surface was locally modified by
the concept of SFJ (Surface Friction Joining) were analyzed. It is noteworthy that the formability of
the surface-modified sheets is greatly improved compared with as-received sheets. The formability
is improved as the tool diameter is increased. It is found that more plastic deformation is
accommodated at modified region during LDH test.
Effects of Microstructure on Mechanical Properties of HRS Processed SUS316L Stainless Steel
Authors: Hiroshi Fujiwara , Nakatani Masashi , Iwahashi Yasuro , Ameyama Kei
Published: March 2009

Mechanical milled SUS316L stainless steel powder is applied to hot roll sintering (HRS)
process. Microstructure and mechanical properties of the HRS material is investigated. Microstructure of
material produced by HRS process consists of the shell and core hybrid microstructure, that is, a shell
structure with nano grains and a core structure with work-hardened coarse grains. The fine grain structure
corresponding to the shell area has (austenite + sigma) nano duplex structure. Work-hardened structure in
the core area composes of an austenite phase. The HRS material demonstrates not only superior strength
but also enough elongation. Mechanical properties are strongly influenced by the shell/core structure,
such as grain size, shell/core size and/or the volume fraction. The shell and core nano-duplex hybrid
microstructure by the HRS process has been proved to be very effective to improve mechanical
properties.
Ring-Rolling Process for Manufacturing Ti-6Al-4V Plane and Profiled Ring-Products
Authors: Kim Kook Joo , Choi Seung Sik , Hwang Chang Yull , Kim Jong Sik , Yeom Jong Taek , Lee Chong Soo
Published: March 2009

Manufacturing processes of Ti-6Al-4V plane and profiled ring-products were
investigated with three-dimensional FEM simulation and experimental analyses. FEM simulation
for the ring-rolling process was used to calculate the state variables such as strain, strain rate and
temperature. To induce the uniform deformation of the profile ring and reduce the applied load, the
final blank was prepared by two-step processes. The mechanical properties of Ti-6Al-4V alloy ring
products made in this work were investigated with tensile and impact tests, and compared with the
specification(AMS-T-81915).
Dynamic Recrystallization during Hot Extrusion in AZ31 and AZ80 Alloys
Authors: Honda M. , Uesugi Tokuteru , Takigawa Yorinobu , Mabuchi Hiroshi , Higashi Kenji
Published: March 2009

Dynamic recrystallization behavior that occurs during the hot extrusion was examined in
two commercial Mg alloys, AZ31 and AZ80 alloys. The initial grain size, d0, and the dynamically
recrystallized grain size, drec, after the extrusion was investigated using optical microscopy. The
dynamically recrystallized grain size decreased with an increasing the Zener-Hollomon parameter.
Cementite Decomposition of Pearlitic Steels during Cold Drawing
Authors: Balak Juraj , Sauvage Xavier , Lee Duk Lak , Lee Choong Yeol , Pareige Philippe
Published: March 2009

Microstructures of cold drawn pearlitic steel wires were investigated by three-dimensional atom
probe (3D-AP) to understand the influence of alloying elements on the decomposition of cementite.
Before cold drawing, Si is mostly located in the ferrite phase, while Cr is located in the Fe3C phase
and the amount of Mn is similar in Fe3C and in ferrite. Higher Si amount leads to higher dissolution
rate of cementite and Cr has a little effect on cementite decomposition during drawing.
Mechanical Milling of Prealloyed Cu-Cr Powders Prepared by Gas Atomization
Authors: Yeo Hwan Kyun , Ahn Sang Ho , Han Kwan Hee
Published: March 2009

In this study, we investigate the effects of high energy milling under Ar atmosphere on
the morphology, size and microstructure of Cu-Cr alloy powders prepared by gas atomization. The
attrition milling using stainless steel balls is performed up to 60 hrs. The observation by SEM and
TEM shows apparent sequential changes of morphology and size of powders similar to those that
are typical for mechanically alloyed elemental powders. Prolonged milling in the steady state
regime produces a nano-crystalline structure, consisting of extremely small grains of 20 to 50 nm in
size and finely dispersed Cr particles. It is also shown that the uptake of Fe from the stainless steel
balls and vessel is appreciable. The microhardness of milled powder increases with the milling time,
reaches its peak and then slightly decreases.
Mechanical Properties and Microstructure of Strip Casted Ag-27%Cu-25%Zn-3%Sn Brazing Alloy
Authors: Lee Kee Ahn , Kim Sung Jun , Kim Moon Chul
Published: March 2009

This work sought to examine the suitability of twin roll strip casting for Ag-27%Cu-
25%Zn-3%Sn brazing alloy (BAg-7A) and to investigate the mechanical properties and
microstructure of the strip. The effect of aging heat treatment on the properties was also studied.
This new manufacturing process has applications in the production of the brazing alloy. XRD and
microstructural analysis of the Ag-27%Cu-25%Zn-3%Sn strip represented eutectic microstructure
of a Cu-rich phase and a Ag-rich matrix regardless of heat treatment. The results of mechanical tests
showed tensile strength of 470MPa, a significant enhancement; and an 18% elongation of the twin
roll casted strip, due mainly to the solid solution strengthening of Zn atoms (~20%) in the Cu-rich
phases. Tensile results showed gradually decreasing strengths and increasing elongation with aging
heat treatment. Microstructural evolution and fractography were also investigated and related to the
mechanical properties.
Studies for the Influences of Welding Parameters of GMA Welded 600MPa Grade TRIP Steel
Authors: Lee Gyeong Choel , Kim Jae Seong , Lee Bo Young , Lee Sang Yul
Published: March 2009

Due to the environmental problem, automotive companies are trying to reduce the
weight of the car body. Therefore, TRIP (TRansformation Induced Plasticity) steels, which have
high strength and ductility, have been developed. However, there are only a few publication
reported on the characteristics of GMA weld on TRIP steel.
In this study, we will evaluate which of the shielding gases, i.e. Ar 100% CO2 100% and Ar 85%
+ CO2 15%, and welding speed make a better quality GMA welded TRIP steel. Bead-on plate
welding and butt welding were performed with various welding conditions. In order to identify
mechanical properties of welded TRIP steel experimental methods including fractography, tensile
test, and hardness test were performed.
The Effect of Post Weld Heat Treatment on Mechanical Properties of Friction-Welded Alloy 718 and SNCRW Stainless Steel
Authors: Kim Nam Yong , Kim Jeoung Han , Kong Yu Sik , Yoon Jong Won , Yeom Jong Taek , Lee Dong Geun , Park Nho Kwang
Published: March 2009

The effect of post weld heat treatment on mechanical properties of friction welded Alloy
718 and SNCRW was investigated. Friction welding tests were carried out at a constant rotation speed
and pressure. Optimum friction condition was found to be the friction pressure of 25kg/cm2, friction
time of 40sec, upset pressure of 80 kg/cm2, and dwell time of 5sec. After friction welding tests, post
weld heat treatments were performed in the temperature range of 500-900°C for 8hrs in order to
investigate the microstructure and mechanical properties of weld joint. Specimens with the post weld
heat treatment at 720°C for 8hrs show optimal mechanical properties. Residual stress of post weld
heat treated specimens was measured to weld joint in the same temperature range. After friction
welding tests on samples with a diameter of 80mm, tensile properties of post-weld-heat-treated and
non-heat-treated samples were compared.
Permanent Mold Casting Practice and Microstructure and Mechanical Properties of Thin-Sectioned ADI Casting
Authors: Moon B.M. , Kim Bong Hwan , Shin Je Sik , Lee Sang Mok
Published: March 2009

For thin-walled casting development of austempered ductile iron (ADI), permanent mold
casting and accompanied heat treatment practice were systematically investigated to suppress and/or
remove chill defects of ductile cast iron (DCI) with various thickness of 2 to 9 mm and to ensure
mechanical properties of the final ADI casting. Si content was increased up to 3.8% to reduce the chill
formation tendency under a high cooling rate. The residual Mg content remarkably affected the
nodule count, while the nodule size and spherodization were proven to have weak relationships.
Austenitizing process followed by austempering was very sensitive to chemical compositions (Si and
Sn) and heat treatment temperature. As a practical application, the steel bar coupler for a structural
frame was tried to produce without subsequent machining.
Improvement of the Accuracy of High Temperature Slab Weight in Continuous Casting
Authors: Kim Seong Yeon , Park Yeong Seon , Park Jong Min
Published: March 2009

In continuous casting, slab weight is normally calculated just after torch cutting of slab using the
process parameters and measured length. Because the weight is dependent on the slab temperature as well as
slab width, the conventional method has the possibility of inaccuracy in calculated slab weight where
contraction ratio of hot-slab was used in weight calculation. In this study, the slab width and surface
temperature were measured using pyrometer simultaneously and used for determining the slab dimension
and high temperature density. Slab density was formulated as a function of slab surface temperature and slab
dimension. The accuracy of slab weight could be improved using this new measured method, and the slab
could be cut with good matching weight with ordered-weight.
Effects of Finishing Rolling Temperature on the Microstructural Behavior for Fe-0.1C Steel as a Function of Niobium Content
Authors: Kang Nam Hyun , Park Inae , Jin Jong Won , Byun Sang Ho , Lee Young Jung , Cho Kyung Mok
Published: March 2009

The demand to replace Fe-V steel with Fe-Nb steel is evolving because of high costs of raw
vanadium material. For the mass production of Fe-Nb steel, the most critical barrier is a poor impact
toughness comparing with that of Fe-V steel. This study covers a microstructural investigation for
ferrite grain size to explain the strength and toughness results as a function of V and Nb contents. The
steel samples were made of three different compositions, i.e., Fe-V steel (Fe-0.05V-0.001Nb),
Fe-V-Nb steel (Fe-0.014V-0.03Nb), and Fe-Nb steel (Fe-0.003V-0.033Nb). Rolling temperature to
initiate was 1150°C for the all experiments. However, rolling temperature to finish was set differently
for two conditions; 950°C and 860°C. The rolling to 860°C decreased the grain size for the ferrite
phase and increased the impact toughness rather than the case of 950°C. The Fe-V-Nb steel exhibited
similar value of the impact toughness with that for the Fe-V steel because of the low rolling
temperature to finish, i.e., 860°C. The whole replace of V with Nb decreased the impact toughness
significantly, however some extent of V content remained with Nb content showed the comparable
toughness to the Fe-V steel by optimizing the controlled rolling process.
Alignment of Primary Phase of a Binary Alloy during Solidification
Authors: Iwai Kazuhiko , Usui Manabu , Asai Shigeo
Published: March 2009

A static magnetic field and an alternating current are imposed on a metallic alloy during
solidification for a crystal alignment of the primary phase. A Sn-10%Pb is selected as a sample
because its primary phase is expected to have an anisotropic nature in magnetic susceptibility. In
the x-ray diffraction pattern of the sample solidified without the magnetic field, the first and second
highest peaks are (101) and (211) planes. On the other hand, those solidified with the magnetic field
are (200) and (220) planes which are magnetically preferred planes. That is, the primary phase
crystals in the sample solidified with the magnetic field are aligned to the specific direction.
Effect of Continuous Casting Parameters on Microstructure and Texture of Gold Bonding Wire for Semiconductor Packaging
Authors: Kim Won Yong , Kim Han Sol , Chung Eun Kyun
Published: March 2009

In this study, we have investigated a texture and microstructure of gold bonding wire by
transmission electron microscope, X-ray diffraction and electron back scatter diffraction according to
process parameters, such as casting, drawing and annealing processes. The gold was cast into 7mm
diameter rods by vertical continuous casting technique, the cast rods were drawn to a final wire size of
25μm, and then the fine wires were annealed. A unidirectional solidification structure having <100>
fiber texture of cast rod was strongly developed depending on casting route and speed. In the sample
with unidirectional microstructure developed in partial it is found that dislocation substructure with
nano-size appeared to display a characteristic feature, while no dislocation substructure is seen in the
sample with complete unidirectional microstructure. Interface stability between solid and liquid may
be responsible for this difference in dislocation substructure. With decreasing casting speed <100>
fiber component became weak. Initial texture plays important role on development of <111> fiber
texture at drawing and final annealing stages. On the basis of results obtained it is suggested that both
the initial texture are important in controlling the texture of gold bonding wire.
Solventless Synthesis of Bi2S3 Nanowires and their Application to Solar Cells
Authors: Wang Z.J. , Qu S.C. , Xu Y. , Chen Y.H. , Zeng X.B. , Liu J.P. , Wu Ju , Wang Z.G.
Published: March 2009

Orthorhombic Bi2S3 (bismuthinite) nanorods and nanowires were synthesized by the
solventless thermolysis of bismuth alkylthiolate precursors. Reactions producing high aspect ratio
nanowires were carried out in air at 225°C with the presence of a capping ligand species, octanoate.
Nanorods with a lower aspect ratio were produced by the same approach with the addition of
elemental sulfur at a lower temperature (~160°C). Current density –Voltage characterization of the
devices under illumination with 500 W Xenon lamp showed the photovoltaic performance. Both the
nanorods and the nanowires hybrid with the polymer show the improved photovoltaic performance
than polymer only. As far as we know, we are the first to apply Bi2S3 nanorods and nanowires to solar
cells with the structure of ITO/PEDOT:PSS/MDMO-PPV:Bi2S3/Al.
Nanocrystalline Diamond Film Produced by Argon Addition in the CH4-H2 Microwave CVD Plasmas
Authors: Askari Syed Jawid , Lu Fan Xiu
Published: March 2009

Diamond coatings on pure titanium substrates are of interest for tribological and
biomedical implants. However, due to the different thermal expansion coefficients of the two
materials, the complex nature of the interlayer formed during diamond deposition, and the difficulty
in achieving very high nucleation density, it is hard to deposit adherent thin diamond layers on
titanium. The aim of the present research was to successfully produce smooth and well adherent
nanocrystalline diamond (NCD) film on a pure Ti substrate using the microwave plasma chemical
vapor deposition (MWPCVD) method. The influence of Argon addition to CH4/H2 plasma on the
crystallinity, morphology and growth of the diamond film deposited by MWPCVD was investigated
using field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), Xray
diffraction (XRD) and Raman spectroscopy.
Visible-Light Photodegradation of Rhodamine B on Carbon Doped Titanium Oxide Thin Film Prepared by Atmospheric MOCVD
Authors: Li Li Na , Gu Jing Hua , Zhang Yue
Published: March 2009

Carbon doped TiO2 and pure TiO2 thin films were prepared by atmospheric metal organic
chemical vapor deposition (MOCVD) method. Both pure TiO2 and carbon doped TiO2 films are in
anatase structure. X-ray photoelectron spectra (XPS) of the carbon doped TiO2 film indicate carbon
atoms occupy oxygen sites and form Ti-C bonds in TiO2 lattice. In UV-VIS absorption spectra, it can
be found that the carbon doped TiO2 film has a red-shifted absorption edge compared with the pure
TiO2 film. In the photocatalytic decomposition experiment of Rh.B, carbon doped TiO2 exhibited
remarkably visible light activity.
Characterization of (Ti, Al) N Films Synthesized by Arc Ion Plating
Authors: Choi Se Weon , Kim Young Chan , Chang Se Hun , Oh Ik Hyun , Kang Chang Seog
Published: March 2009

(Ti, Al) N coating had been deposited by Arc Ion Plating, in an atmosphere of nitrogen. The
structure of the coatings was examined as a function of deposition conditions by X-ray diffraction,
and the crystallographic orientation was determined by use of a texture coefficient. The coatings on
ground titanium substrates developed a strong (111) orientation from the earliest stages of growth,
although the degree of orientation was dependent on deposition conditions. TiAlN coatings, however,
showed relatively multiple orientations mainly of (111) and (200). Furthermore, TiAlN films
demonstrated superior corrosion resistance in a molten aluminum alloy at 680°C. This paper
described in detail the corrosion and mass loss phenomena related to this steel-cast metal interaction.
Low-Temperature Deposition of Amorphous Carbon Films for Surface Passivation of Carbon-Doped Silicon Oxide
Authors: Yamaoka Keisuke , Terai Yoshikazu , Okada Naomichi , Yamaguchi Takashi , Yoshizako Yuji , Fujiwara Yasufumi
Published: March 2009

Low-temperature plasma-enhanced chemical vapor deposition of amorphous carbon
(a-C:H) films was investigated for surface passivation of carbon-doped silicon oxide (SiOCH) films.
The a-C:H films were deposited using CH4 and Ar gases at 40–65°C. FT-IR results showed that the
deposited films are a-C:H which incorporates hydrocarbon groups. In current−voltage measurements,
the a-C:H showed a low leakage current of ~10–10 A/cm2 in air, indicating that the a-C:H films have a
potential as a surface passivation layer to prevent moisture absorption in air. The insulating properties
of room-temperature deposited SiOCH covered by the a-C:H strongly depended on radio frequency
(RF) power in the SiOCH deposition. In the SiOCH film deposited at high RF power of 200 W, the
resistivity in air was improved by the a-C:H passivation.