bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmentally Benign Adhesive Synthesized by Dispersion Copolymerization of Styrene and Butyl Acrylate
Authors: Zhang Jun Ying , Dou Peng
Published: March 2009

Environmentally benign adhesive was synthesized by dispersion copolymerization of
styrene(St) and butyl acrylate (BA) in an ethanol medium with benzoyl peroxide (BPO) as the initiator
and poly(vinylpyrrolidone) as the stabilizer in the presence of acrylic acid(AA) as the functional
monomer. The effect of the concentration of stabilizer, initiator and functional monomer on the
conversions, molecular weights and molecular weight distributions was investigated. The results
show that the conversions almost keep invariable with the increasing of stabilizer concentration, but
the molecular weights increase and molecular weight distributions decrease. Conversions increase
with the increasing of initiator concentration, but the molecular weights and molecular weight
distributions decrease. However with the increasing of functional monomer concentration,
conversions and molecular weight distributions increase but the molecular weights decrease.
Microstructure and Mechanical Property of 3D Textile C/SiC Composites Fabricated by Chemical Vapor Infiltration
Authors: Zhao Dong Lin , Yin Hong Feng , Luo Fa , Zhou Wan Cheng
Published: March 2009

Three dimensional textile carbon fiber reinforced silicon carbide (3D textile C/SiC)
composites with pyrolytic carbon interfacial layer were fabricated by chemical vapor infiltration.
The microstructure and mechanical property of 3D textile C/SiC composites were investigated. A
thin pyrolysis carbon layer (0.2 ± μm) was firstly deposited on the surface of carbon fiber as the
interfacial layer with C3H6 at 850°C and 0.1 MPa. Methyltrichlorosilane (CH3SiCl3 or MTS) was
used for the deposition of the silicon carbide matrix. The conditions used for SiC deposition were
1100°C, a hydrogen to MTS ratio of 10 and a pressure of 0.1 MPa. The density of the composites
was 2.1 g cm-3. The flexural strength of the 3D textile C/SiC composites was 438 MPa. The 3D
textile C/SiC composites with pyrolytic carbon interfacial layer exhibit good mechanical properties
and a typical failure behavior involving fibers pull-out and brittle fracture of sub-bundle. The real
part (ε′) and imaginary part (ε″) of the complex permittivity of the 3D-C/SiC composites are
51.53-52.44 and 41.18-42.08 respectively in the frequency range from 8.2 to 12.4 GHz. The
3D-C/SiC composites would be a good candidate for microwave absorber.
Application of Acoustic Emission in Control of High-Pressure Pipe Overstraining
Authors: Nowak Marek , Baran I. , Schmidt J. , Plochocki Z.
Published: March 2009

The article describes the application of AE technique in control and evaluation of the pipe
overstraining process. The trials of overstraining were conducted according to a programme of pipe
loading with internal pressure, developed and adjusted to the examined pipe material.
In the studies two systems of acoustic emission were used, viz. PAC Mistras 2001 and Vallen
AMSY. The procedure adopted in the development of evaluation criteria based on an analysis of the
recorded acoustic events was described. Next, the criteria of evaluation were presented. The
effectiveness of the applied method, the validity of the adopted criteria, and the consistency of the
obtained quantitative results were checked during tests performed by other NDT methods.
A comparative analysis was made to serve as a complementary tool in final evaluation of the pipe
overstraining process done by AE technique.
Evaluation of Repair Effect for Deteriorated Concrete Piers of Intake Dam Using AE Activity
Authors: Shiotani Tomoki
Published: March 2009

Deteriorated concrete structures are repaired by means of grouting. In order to evaluate the
repair effectiveness two NDT techniques namely seismic tomography and acoustic emission are
applied. Using traveling time of elastic waves, structural velocity is estimated. AE activity is
monitored along with water pressurization of the permeability test. As a result, contrary to the
common expectation that the velocity increase after filling with grouting agent, enormous amount of
velocity drop was obtained after repair due to the incomplete developing process of grout material,
whereas AE activity showed dramatic decrease after repair. Furthermore after comparison of those
results to the quantity of grouting material, it became clear that damage indices based on AE activity
exhibited well the actual damage of concrete structures.
Guided Wave Acoustic Emission from Fatigue Crack Growth in Aluminium Plate
Authors: Lee C.K. , Scholey Jonathan J. , Wilcox Paul D. , Wisnom M.R. , Friswell Michael I. , Drinkwater B.W.
Published: March 2009

Acoustic emission (AE) testing is an increasingly popular technique used for nondestructive
evaluation (NDE). It has been used to detect and locate defects such as fatigue cracks in
real structures. The monitoring of fatigue cracks in plate-like structures is critical for aerospace
industries. Much research has been conducted to characterize and provide quantitative
understanding of the source of emission on small specimens. It is difficult to extend these results to
real structures as most of the experiments are restricted by the geometric effects from the specimens.
The aim of this work is to provide a characterization of elastic waves emanating from fatigue
cracks in plate-like structures. Fatigue crack growth is initiated in large 6082 T6 aluminium alloy
plate specimens subjected to fatigue loading in the laboratory. A large specimen is utilized to
eliminate multiple reflections from edges. The signals were recorded using both resonant and nonresonant
transducers attached to the surface of the alloy specimens. The distances between the
damage feature and sensors are located far enough apart in order to obtain good separation of
guided-wave modes. Large numbers of AE signals are detected with active fatigue crack
propagation during the experiment.
Analysis of experimental results from multiple crack growth events are used to characterize the
elastic waves. Experimental results are compared with finite element predictions to examine the
mechanism of AE generation at the crack tip.
Acoustic Emission in Wide Composite Specimens
Authors: Scholey Jonathan J. , Wilcox Paul D. , Lee C.K. , Friswell Michael I. , Wisnom M.R.
Published: March 2009

Acoustic emission (AE) is an attractive technique for the structural health monitoring
(SHM) of aerospace systems. To reach its full potential in this role a quantitative approach must be
adopted to study damage mechanisms in composite materials.
In this paper, some of the practical issues regarding acoustic emission testing in composites are
addressed. A model describing Lamb wave propagation through plates is described and used to
make phase velocity and attenuation measurements in both aluminium and carbon fibre reinforced
plastic plates. Results are then implemented in the frequency domain to conduct an experimental
study of normal incidence Lamb wave reflections. Comparisons are made with finite element
analysis (FEA) models with good results.
Detection of Incipient Damage in Large Rolling Element Bearings
Authors: Rogers Leonard M.
Published: March 2009

The paper describes a methodology for the reliable detection of incipient damage due to
fatigue, fretting and false brinelling in large, heavily loaded rolling element bearings such as found
in pedestal slewing cranes and ship azi-pod propulsors. It has been found that combining acoustic
emission source location and spectrum analysis of the associated time-domain signatures has
produced a powerful diagnostic tool for the detection of micro-damage to the various working faces
of the bearing under variable speed and loading conditions, before any metal loss is evident in the
bearing lubricant. Other sources of acoustic emission such as fretting at contact faces elsewhere in
the body of the bearing and fluid turbulence can be resolved and quantified so as not to interfere
with the diagnosis of bearing condition. Results are presented for new and damaged bearings, where
the true condition has been verified when the bearings were subsequently replaced.
Use of Advanced A.E. Analysis for Source Discrimination Using Captured Waveforms
Authors: Cole P.T. , Carlos M.
Published: March 2009

Conventional methods of acquiring and using acoustic emission (AE) discard the raw
signal waveform after extracting signal features from it. The main reason for this is the number of
bytes required to save hundreds of thousands of AE waveforms, using a modern high speed multichannel
system the hard-drive may be quickly filled. One side effect of this “feature extraction”
approach is that information is thrown away with the wave-form. The advent of systems capable of
acquiring AE waveforms on all channels has opened up the opportunity to use this extra data to get
more information about the source and the transmission path. This paper describes the use of
acoustic emission waveforms to aid source discrimination, and presents data acquired during
pressure testing of a slug-catcher.
The Influence of Peak Temperature and Deformation on Welding CCT Diagram of Eutectoid Carbon Steel
Authors: Maalekian Mehran , Lendinez M.L. , Kozeschnik Ernst , Brantner Hans P. , Cerjak Horst
Published: March 2009

The welding continuous cooling transformation (WCCT) behavior of eutectoid carbon
steel was investigated in different peak temperatures and in the undeformed and deformed
conditions. The corresponding WCCT and welding continuous cooling compression transformation
(WCCCT) diagrams were constructed by means of dilatometric and metallographic analyses in
addition to hardness measurements. It was found that the higher austenitizing temperature slightly
accelerates pearlitic transformation, i.e., it shifts the WCCT diagram to shorter times. Furthermore,
heavy hot deformation of austenite could strongly promote the formation of pearlite, that is, the
WCCCT diagram moved toward the top left corner compared to the WCCT diagram, while
martensite start temperature was lowered slightly, which is a characteristic of a displacive
transformation mechanism.
In Situ Observation of Phase Transformations and their Effects in 9-12%Cr Steels during Welding
Authors: Mayr Peter , Palmer T.A. , Elmer J.W. , Cerjak Horst
Published: March 2009

A basic requirement for the production of large power plant components from
ferritic/martensitic 9-12% Cr steels is good weldability. Weldments in these steels are often
reported as the weak spots. In this work the weldability of a creep resistant 9% Cr steel is discussed.
Different methods are utilized to characterize the microstructural evolution during different welding
cycles and the following post weld heat treatment, as well as the resulting mechanical properties.
Heat affected zone (HAZ) simulation using a thermo-mechanical testing device GLEEBLE 1500 is
performed to study the microstructural evolution and changes in the mechanical properties in the
different parts of the HAZ. Specimens exposed to peak temperatures higher than 1150°C showed a
minimum of impact toughness after post weld heat treatment (PWHT). In situ X-ray diffraction
experiments with synchrotron radiation are used to observe phase transformations during heating to
elevated temperatures, where delta ferrite formation was observed at temperatures higher than
1250°C.
Selective Oxidation during the Austenitic Annealing of a CMnSi Steel
Authors: van de Putte Tom , Zermout Zinedine , Loison Didier , Claessens Serge , Penning Jan
Published: March 2009

High strength multiphase CMnSi steel is increasingly used in passenger cars. Si and Mn alloying
levels are typically in the range of 1-2% in mass. While Si improves the mechanical properties, it
considerably deteriorates the galvanisability of steel. Residual water vapour in the reducing gas
atmosphere during the intercritical or austenitic annealing results in the selective oxidation of Si and
Mn at the steel surface. Besides Mn and Si, C is oxidized as well at the steel surface, leading to the
formation of CO gas and decarburisation of the steel surface. This decarburisation has a major
influence on the phase composition in the steel surface region: it shifts the ferrite to austenite
transformation to higher annealing temperatures, leading to differences in surface and bulk
microstructure. The phase composition influences the solubility and diffusivity of all alloying
elements near the surface. The evolution with temperature of the selective oxidation at the steel
surface has been studied by interrupted annealing in a protective atmosphere containing residual
water vapour. The influence of the annealing temperature on the selective oxidation of Mn and Si is
characterized by XPS (X-ray Photo-electron Spectroscopy) analysis.
Analysis of the Intermetallic Compound Formed in Hot Dip Aluminized Steel
Authors: Kim Kee Hyun , van Daele Benny , Van Tendeloo Gustaaf , Chung Yong Sug , Yoon Jong Kyu
Published: March 2009

A hot dip aluminising process was carried out with a 1mm steel sheet dipped into the
Al-10at.% Si melt in an automatic hot-dip simulator. When steel and liquid aluminium are in contact
with each other, a thin intermetallic compound (IMC) is formed between the steel and the aluminium.
The analysis and identification of the formation mechanism of the IMC is needed to manufacture the
application products. Energy dispersive X-ray spectroscopy (EDX) and electron probe microanalysis
(EPMA) are normally used to identify the phases of IMC. In the Al-Fe-Si system, numerous
compounds with only slight differences in composition are formed. Consequently, EDX and EPMA
are insufficient to confirm exactly the thin IMC with multiphases. In this study, transmission electron
microscopy (TEM) analysis combined with EDX was used. The TEM sample was prepared with
focused ion beam (FIB) sampling. The FIB lift-out technology is used to slice a very thin specimen
with minimum contamination for TEM analysis. It is clearly shown that the IMC consists of Al-27 at.
% Fe-10 at. % Si and is identified as Al8Fe2Si with a hexagonal unit cell (space group P63/mmc). The
cell parameters are a= 1.2404nm and c= 2.6234nm.
Study of Indium Oxide Rod-Like Structures Synthesized Using Metalorganic Chemical Vapor Deposition
Authors: Kim Hyoun Woo , Shim S.H.
Published: March 2009

We have investigated the morphological changes with varying the substrate temperature in
the range of 350-400°C, in synthesizing the indium oxide (In2O3) rod-like structures by using the
metalorganic chemical vapor deposition method. The as-synthesized rod-like structures was aligned
perpendicular to the Si substrate. X-ray diffraction (XRD) and selected area electron diffraction
(SAED) analyses demonstrated that the rods had a cubic In2O3 structure. PL spectra of the In2O3
rod-like structures exhibited the visible light emission. We discussed the possible growth
mechanisms.
Interfacial Reaction and Bump Shear Property of Electroplated Sn-37Pb Solder Bump with Ni under Bump Metallization during Multiple Reflows
Authors: Koo Ja Myeong , Jung Seung Boo
Published: March 2009

The interfacial reactions and bump shear properties of the electroplated Sn-37Pb (in wt.%)
solder bumps with the Ni under bump metallization (UBM) were investigated as a function of the
number of reflows. A continuous facetted Ni3Sn4 intermetallic compound (IMC) layer was formed at
the interface between the solder bump and the Ni UBM during reflow. The thickness of the Ni3Sn4
IMC layer was 0.41 μm after 1 reflow, and then the thickness of the IMC layer increased with
increasing the number of reflows. The shear properties of the bumps indicated the maximum values
after 1 reflow, and then decreased with increasing the number of reflows. The fracture surfaces of the
bumps showed ductile failure characteristics after 1 reflow, and then the fraction of the brittle fracture,
induced by the IMC formed at the interface, increased with increasing the number of reflows.
The Study of Immobilization Thermal-Sensitive Hydrogel onto ePTFE Film Use the Cold Plasma and Photo-Grafting Technique
Authors: Chen Ko Shao , Chen Su Chen , Yeh Yi Chun , Lien Wei Cheng , Lin Hong Ru , Yang Jen Ming
Published: March 2009

Expanded polytetrafluoroethylene (ePTFE) is a bioinert material. To improve the ePTFE film
biocompatibility, the cold plasma technology was used with acetic acid as monomer to deposit onto
ePTFE film and then (N-isopropylacrylamide) was grafted onto the surface by photo-grafting. The
characteristics of the surface were evaluated with X-ray photoelectron spectroscopy (XPS), FTIR
and water contact angle. It was found that the contact angle of water on the untreated ePTFE
significantly decrease from125° to 72° after ePTFE film being treated with acetic acid plasma
deposition treatment. Due to the hydrophilicity of poly(N-isopropylacrylamide), the contact angle
of water on the ePTFE-g-NIPAAm approached to 0°.
Fabrication of MgB2/Al Composite Material
Authors: Morobayashi Masaru , Matsuda Kenji , Saeki T. , Ikeno Susumu , Nishimura K. , Mori Katsunori
Published: March 2009

Superconductive MgB2/Al composite material with low and high volume fractions of
particles were fabricated by our special pre-packing technique and 3-dimensional penetration
casting 3DPC method. The composite material showed homogeneous distribution of MgB2 particles
in the Al-matrix with neither any aggregation of particles nor defects such as cracks or cavities. The
critical temperature of superconducting transition (TC) was determined by electrical resistivity and
magnetization to be about 37 ～39K.
Microstructures and Mechanical Properties of Al/Al2O3 Cermet Composites Reinforced by Al/Al2O3 Core-Shell Particles
Authors: Kou Hua Min , Pan Yu Bai , Guo Jing Kun
Published: March 2009

Al/Al2O3 cermet composites were fabricated by hot-pressing at the temperature range of 1350~1450oC from commercial γ - Al2O3 reinforced by Al/Al2O3 core-shell particles, which were synthesized via calcining the Al/AlOOH·nH2O core-shell particles prepared by wet-chemical based method. This newly designed aluminum coated with alumina composite structure can not only reduce or resist the oxidization of Al at elevated temperature but also make it possible to control inter-particle and particle-matrix interactions, and this predesigned structure is expected to improve the following sintering ability and therefore the properties of final products.
Refine Yttria Powder and Fabrication of Transparent Yb,Cr:YAG Ceramics
Authors: Wu Yu Song , Li Jiang , Pan Yu Bai , Guo Jing Kun , Liu Qian
Published: March 2009

Commercial Y2O3 powders were subjected to high energy ball milling in a planetary
ball mill using high purity alumina balls and vial. The refined Y2O3 power ,with
commercial high-purity Al2O3, Cr2O3 and Yb2O3 powders, were used as raw
materials. Transparent ytterbium and chromium codoped yttrium aluminum garnet
(Yb,Cr:YAG) ceramics were fabricated by a solid-state reaction method. The
Yb,Cr:YAG ceramics exhibit a pore free structure and the average grain size is about
10 micron. The strong absorptions at 940 and 968 nm of Yb3+ are suitable for InGaAs
diode laser pumping, and there is an absorption band at 1030 nm, which is suitable for
passive Q-switch laser output at 1030 nm. Transparent Yb,Cr:YAG ceramics may be a
potential material for compact, efficient, high-stability diode-laser-pumped passive
Q-switched solid-state lasers.
Influences of Strontium Addition and Whisker Content on Solidification Behavior of SiCw/Al-18Si Metal Matrix Composites
Authors: Wei Hong Mei , Geng Lin , Zhang Xue Xi
Published: March 2009

Solidification behavior of SiCw/Al-18Si metal matrix composites (MMCs) was studied by
scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential
scanning calorimeter (DSC) in order to reveal the effects of strontium addition and whisker content.
The results show that the Si phase does not nucleate on SiC whisker surface. With the increasing of
SiC whisker content, solidification onset and peak temperatures of primary Si decrease. Sr addition
lowers solidification onset and peak temperatures of primary Si, and reduces its size. Whisker content
has larger effects on solidification onset and peak temperatures of primary Si without Sr addition than
that of primary Si with Sr addition.But solidification onset and peak temperatures of eutectic are
barely affected by whisker content and Sr addition.
Physicochemical Transport Properties of Aqueous Sodium Metaborate Solutions for Sodium Borohydride Hydrogen Generation and Storage and Fuel Cell Applications
Authors: Cloutier Caroline R. , Alfantazi Akram , Gyenge Elod
Published: March 2009

The conductivity and viscosity of aqueous solutions of NaBO2 were measured as a function of
concentration at 25oC. Conductivity data was analyzed with various Kohlrausch correlations and the
limiting molar conductivity of the BO2
- ion at infinite dilution was estimated to be of 30.59 S.cm2/mol.
From this value, the mobility, diffusion coefficients and transference number for the BO2
- ion were
calculated as 3.17x10-4 cm2/s.V, 8.14x10-6 cm2/s, and 0.379 respectively. Ion-solvent and ion-ion
interactions were studied with Jones-Dole type correlations, which were employed to analyze the
viscosity data. A value of -0.4660 1/M was estimated for the BO2
- B- coefficient.
Temperature Distribution within a Compressed Gas Cylinder during Fast Filling
Authors: Dicken C.J.B. , Mérida W.
Published: March 2009

Currently, pressurized gas is the leading technology for vehicular on-board
hydrogen storage. During refueling, the hydrogen is expanded from the high-pressure
fueling station cylinders, into the “empty” vehicle cylinder. The mass of the gas inside
a cylinder can be calculated from the knowledge of the pressure and average gas
temperature. However, during the fill process, the compression of the gas inside the
cylinder leads to a rapid increase in temperature, this phenomenon along with the
continuous introduction of cooler gas creates an evolving spatial distribution of gas
temperature within the cylinder. In order to determine a correlation between the massaveraged
gas temperature and local measurement of gas temperature, this study
presents a CFD model of the filling of a hydrogen compressed gas cylinder. The
model developed in this study is 2D and axi-symmetric, and solves the governing
equations for compressible, unsteady, viscous turbulent flow. The model incorporates
real gas effects, convective heat transfer from the gas to the cylinder walls and
conduction through the cylinder walls to ambient. The results of the model show a
large spatial variation of gas temperature within the cylinder during filling. The
modeling results also help to identify the optimum location for the onboard gas
temperature sensor such that the local measurement best represents the mass-averaged
temperature of the gas within the cylinder. Hence allowing for the calculation of the
mass of gas within the cylinder without using an expensive flow meter.
The Influence of Strain on Semi-Solid Behavior in AC4C Aluminum Alloy Billet by One Way Torsion Working
Authors: Sugie Norihisa , Furui Mitsuaki , Anada Hiroshi
Published: March 2009

This study was investigated about that behavior of α phase during recrystallization
process and the influence of the amount of strain on semi-solid structure of AC4C aluminum alloy
which was processed by one way torsion working.
AC4C aluminum alloy billets having a diameter of 35mm and a length of 400mm were
torsioned by a single side torsion machine. The maximum strain (γmax) of the specimens in this
experiment was 0.88. The specimens were etched for the microstructure observation by optical
microscope.
The casting material (γ＝0) and the torsion material (γ＝0.73) were remained dendrite structure
from room temperature to 565°C. The casting materials had grain-shaped structure when they
reached to 585°C which is an eutectic temperature in this alloy. However the torsion working
material had it when they reached to 577°C from eutectic temperature on down. In semi-solid
region, the structure of the torsion working material was finer than that of casting material and
became a more grain-shaped structure. The casting material which was heated to the eutectic
temperature was changed to dendrite structure again. However the torsion working material was
remained grain-shaped structure.
Annealing Effect on the Thermoelectric Properties of Hot Extruded Bi2(Te0.94Se0.06)3+0.07wt%I+0.03wt%CuBr+0.02wt%Te Compound
Authors: Min Wang Kee , Hwang Sung Doo , Lee Chang Ho , Park Young Do , Kim Yang Do , Kim Young Seok , Park Ik Min , Park Yong Ho
Published: March 2009

The n-type Bi2(Te0.94Se0.06)3 thermoelectric compound was prepared by the direct
extrusion process using the powder as raw materials. Hot extruded specimens were annealed at 200°C
and 350°C for 2hrs. The electrical conductivity, thermoelectric power and thermal conductivity of hot
extruded and annealed specimens were measured at room temperature. The fractographs of the
specimens showed that the grain size became coarser and a lot of porosities were generated during
annealing process. The power factor value (PF) decreased with increasing the annealing temperature.
The electric conductivity and thermal conductivity of the specimens also decreased with the increase
of annealing temperature. This may be reasoned that the generated porosities affect the thermal
conductivity of the specimens prepared in this study. The figure of merit (Z) value of the annealed
specimens at 350°C was improved about 10%. The highest Z value of the specimens annealed at
350°C was 2.0 x 10-3/K among the prepared specimens.
Solidification Behavior of Fe-Base Amorphous Alloys during Twin-Roll Strip Casting
Authors: Oh Yoon S. , Lee Jung G. , Kim Choong Nyun Paul , Kim Nack
Published: March 2009

Solidification behavior of two Fe-base amorphous alloys during twin-roll strip casting has
been investigated in the present study. Continuous cooling transformation (CCT) diagrams of both
alloys were calculated using the heterogeneous nucleation theory coupled with thermal data obtained
during cooling. Cooling sequence during twin-roll strip casting was also simulated. These were used
for the determination of the optimum twin-roll strip casting conditions at which desirable
solidification behavior could be achieved. It shows that twin-roll strip casting can continuously
fabricate sheet product of Fe-base bulk amorphous alloys, despite their higher liquidus temperatures
and larger differences between liquidus and glass transition temperatures (Tg) than those of other
easier glass-forming bulk amorphous alloys.
Porosity, Damage Evolution and Fracture in Die-Cast Magnesium Alloy AM60B
Authors: Weiler J.P. , Wood J.T. , Klassen R.J. , Maire Éric , Berkmortel R. , Wang G.
Published: March 2009

A series of AM60B, die-cast magnesium alloy specimens have been examined using xray
tomography at spatial resolutions from 1 – 20μm and further characterized in uniaxial tension.
This paper first reports the utility of a critical strain model to link the local area fraction of porosity
and the fracture strain. A discussion of the trade-off between predictive accuracy and the spatial
resolution of the imaging technique is also presented in order to address the technological
implications of these results. In the second half of the paper, serial tomographic imaging is used to
illustrate the evolution of damage with increasing uniaxial strain. The implications are discussed
with respect to numerical modeling of the performance of die-cast magnesium components.
High Temperature Deformation Behavior of Strip-Cast AZ31 Mg Alloy
Authors: Lee B.H. , Bang Won Kyu , Ahn Sang Ho , Lee Chong Soo
Published: March 2009

In this study, optimum processing conditions for strip-cast AZ31 Mg alloy was
investigated on the basis of processing map and microstructural analysis. To obtain the processing
map, isothermal compression tests were carried out to a strain of 0.5 at temperatures of 200 ∼ 400°C
with the strain rates of 0.01 ∼ 10s-1. It was found that maximum efficiency indicating the optimum
processing condition occurred at 300°C and 10s-1. The possible deformation mechanisms operating
at high temperature was also discussed.
Influence of Additions Sb on Mechanical Properties and Deformation Features of AZ31-Mg Alloy
Authors: Wang Ling , Tian Su Gui , Sohn Keun Yong , Kim Kyung Hyun
Published: March 2009

The mechanical properties and deformation features of AZ31-x%Sb alloys have been
studied by means of the measurement of the ultimate tensile properties (UTS) and TEM observation.
Results show that the UTS of AZ31 alloy is effectively enhanced to 297 MPa from 222 MPa, by
additions of 0.84% Sb element, at room temperature, and the ultimate tensile strength of the alloy is
still maintained up to 189MPa as temperature elevated to 200°C. Contrast analysis shows that the
deformation mechanisms of AZ31-0.84%Sb alloy are twins and dislocations activated on basal and
non-basal planes. The alloy displays the different deformation features at different deformation
conditions.
Hot Cracking Susceptibility of Ternary Mg-Al-Ca Alloys
Authors: Cao G. , Kou Sindo
Published: March 2009

Hot cracking of ternary Mg-Al-Ca alloys in permanent mold casting was studied. The
alloys are the base of some potential creep-resistant Mg alloys. The Mg-xAl-yCa alloys included
Mg-4Al-1Ca, Mg-4Al-2Ca, Mg-4Al-3Ca, Mg-4Al-4Ca, Mg-5Al-3Ca, and Mg-6Al-3Ca.
Constrained-rod casting was conducted with a steel mold. Rods were cast with their ends enlarged
to act as anchors, which kept the rods from free contraction and thus induced tension in the rods to
cause cracking during solidification. The susceptibility to hot cracking was evaluated based on both
the widths and locations of cracks in the resultant castings. Both binary Mg-4Al and commercial
alloy AZ91E, which is known to have a low susceptibility to hot cracking, were also included for
comparison. It was found that within the composition range studied, the crack susceptibility
decreased significantly with increasing Ca content (y) but did not change much with the Al content
(x).
Modeling Relations between Processing, Microstructure and Mechanical Properties of Porous Bioceramics
Authors: Tancret Franck , Bouler Jean Michel
Published: March 2009

Biphasic calcium phosphate (BCP) bioceramics, for use as resorbable bone substitutes,
containing both isolated macropores and interconnected micropores, have been fabricated by
sintering, using naphtalen particles as a porogen to produce macropores. The resulting ceramics
contain ~ 45% macropores and various amounts of microporosity. Mechanical properties
(compression and bending strength, toughness and hardness) have been measured and modeled by
combining two approaches, at two different scales: the one describes the mechanical properties of a
partly sintered stacking of grains, supposed to account for the interconnected microporosity, the
other one holds in the case of closed and isolated macropores within a continuous matrix. The
material is then represented as a quasi-continuous matrix containing macropores, the matrix being
itself microporous. The model also considers that fracture always initiates on a macropore, which
allows to set a correspondence between fracture toughness and fracture stress equations. The
mechanical tests performed on the sintered ceramics tend to validate the modeling approach.
Modeling and Sensitivity Study of the Induction Hardening Process
Authors: Barka N. , Bocher Philippe , Brousseau J. , Galopin M. , Sundararajan S.
Published: March 2009

Induction heating is a case hardening process used to improve performance of machine
components by producing a hard martensitic microstructure and high compressive residual stresses
at the surface layer. A reliable numerical model able to predict the hardness profile would shorten
process development. However, the accuracy and the efficiency of the model are restricted by the
coupling complexity between the electromagnetic and thermal fields, and the nonlinear behaviour
of the material properties. The paper analyzes the sensitivity of the material properties values and of
the finite element meshing onto the predictive modeling of the case hardening profiles. The material
used is SAE-4340 low-alloy steel. The simulations are done using a computer-modeling software
(Comsol) and the sensitivity analysis is conducted by using an experimental design method.
Modelling Chi-Phase Precipitation in High Molybdenum Stainless Steels
Authors: Xu W. , San Martin D. , Rivera-Díaz-del-Castillo Pedro E.J. , van der Zwaag Sybrand
Published: March 2009

High molybdenum high strength stainless steels can contain the so-called Chi phase
(Fe36Cr12Mo10). The presence of this phase, which normally occurs at grain boundaries,
depletes the chromium content leading to intergranular corrosion. This may cause alloy
embrittlement during long term use. The presence of such phase has proven to be highly
sensitive to alloy processing parameters such as the cooling rate after a final heat treatment.
The present work provides a model to quantify the effects of processing parameters aimed at
controlling the Chi phase. The model is based on nucleation and growth classical theories
involving capillarity effects for the early stages; it is applied to a range of heat treatment
conditions and compared to experimental results.
Block Treatment of Multi-Layer Wafers for the Development of a Numerical Model of a 300mm Batch Heat Treatment Furnace
Authors: Ko Eun Yi , Yi Kyung Woo
Published: March 2009

Of all the processing stages for wafers, interior temperature distribution in thermal
treatment furnaces has a great influence on wafer properties. Therefore, internal temperature
distribution is a key factor for operating a furnace. However, it is practically impossible to directly
measure temperatures within the furnace, and consequently the need for a reliable numerical model to
analyze temperature distribution is becoming increasingly urgent. Exact modeling of the processing
is very difficult because the structure of the furnace used for thermal treatment is very complex, with
large numbers of Si wafers stacked within. Therefore, simplified modeling is necessary. The
modeling strategy of the present study is to reduce the radiation calculation domain and simplify the
model by replacing the wafer stack region with a single block. It is necessary to determine the vertical
and horizontal effective thermal conductivities of the block to reflect radiation heat transfer between
wafers. In this study, calculations were performed through numerical experimentation, using r k as
the heat transfer coefficient in the direction of the radius, and v k for the vertical direction. Using
these calculated property values, the temperature distribution within a 300mm thermal treatment
furnace can be obtained.
Preparation of Nanocrystalline Inorganic Materials by Impulse Plasma in Liquid
Authors: Omurzak Uulu Emil , Matsuda Mitsuhiro , Ihara Hirotaka , Mashimo Tsutomu , Sulaimankulova Saadat
Published: March 2009

We developed a synthesis method of nanomaterials by the impulse plasma in liquid. The
method is based on the low voltage pulsed plasma. The apparatus is very simple and does not require
vacuum system, high-energy, cooling system, but can evaporate even refractory metals. Preparation
experiments of nanomaterials by using Impulse Plasma in Liquid method were performed. We
succeeded in synthesis of nanocrystals of some metals, TiO2, and fullerene C60. The synthesized TiO2
powder consists of fine-dispersed particles of rutile and anatase phases with 5-15 nm grain size. Pure
fullerene C60 was prepared by dispersion of graphite electrodes by Impulse Plasma in toluene. It was
suggested that the present method can be effectively used for nanomaterials preparation.
Preparation and Characterization of Bimetallic Nanoparticles Ptx-Pd1-x Supported on Silica
Authors: Castillo N. , García L.A. , Vázquez Z. A. , Díaz Barriga L. , Pérez R.
Published: March 2009

Ptx-Pd(1-x) nanoparticles supported on amorphous silica (SiO2) were prepared by wetness
impregnation techniques with choroplatinic acid (H2PtCl6) and palladium chloride
(PdCl4) with different concentrations of Pt and Pd at about 1% in overall metallic
weight. The purpose of this study was to evaluate the physical properties as
physisorption (BET), X Ray Diffraction XRD, High Resolution Electron Microscopy
HREM, Transmission Electron Microscopy TEM couple with XEDS energy dispersive
X-ray spectrometry and chemical properties to determine the activity in cyclohexene
reaction of these materials supported.
Bimetallic nanoparticles are made of a single solid solution of Pt and Pd atoms, and the
particles diameter of about 3-5 nm was estimated by HREM and Bright field image, the
Pt-Pd nanoparticles were found mainly to have truncated cuboctahedral shape with fcc
packing,. by using energy dispersive X-ray spectrometry (XEDS) and their values were
found to be close to the stochiometric relative concentrations in weight of the metals in
the precursor aqueous solution.
Effects of Constitutive Parameters on Thickness of Phase Transformed Adiabatic Shear Band for Ductile Metal Based on Johnson-Cook and Gradient Plasticity Models
Authors: Wang X.B.
Published: March 2009

Gradient-dependent plasticity where a characteristic length is involved to consider the
microstructural effect (interactions and interplaying among microstructures due to the heterogeneous
texture) is introduced into Johnson-Cook model considering the effects of strain-hardening, thermal
softening and strain rate sensitivity. Effects of initial static yield stress, strain-hardening coefficient
and exponent, strain-rate and thermal-softening parameters on the occurrence of phase
transformation and the thickness of phase transformed adiabatic shear band (ASB) in deformed ASB
are numerically investigated. Higher initial static yield stress, strain-hardening coefficient, strain-rate
parameter and lower strain-hardening exponent lead to earlier occurrence of phase transformation
(lower plastic shear strain). Effect of thermal-softening parameter on plastic shear strain
corresponding to the onset of phase transformation is not monotonous. Transformed ASB is located
at the center of deformed ASB since the position has higher temperature exceeding the temperature of
phase transformation. The thickness of transformed ASB increases with decreasing flow shear stress
and the increasing tendency becomes slow. For the same flow shear stress, the thickness of
transformed ASB is wider for higher initial static yield stress, strain-hardening coefficient and
exponent, strain-rate and thermal-softening parameters. Compared with classical elastoplastic theory
applicable to completely homogenous material, gradient-dependent plasticity considering the
microstructural effect predicts that phase transformation occurs earlier and that the thickness of
transformed ASB changes with flow shear stress.
Effect of Technological Parameters on the Profile Extrusion Process
Authors: Yan Hong
Published: March 2009

The non-homogeneous metal flow during the extrusion process is well controlled by
introducing a reflecting non-equilibrium parameter of metal flow —— the mean-square deviation of
velocity ( SDV ) in this paper. The finite deformation elastoplastic finite element method is used to
carry out the numerical simulation research on the profile extrusion process with the different
extrusion parameters (such as extrusion ratio, frictional factor). The varied laws of the extrusion
pressure, SDV and stress-strain fields with the extrusion parameters are obtained. It is a theoretic
consideration to optimize the technological parameters in the profile extrusion process.
Crystal-Grain Refinement of Materials under an Ultra-Strong Gravitational Field
Authors: Iguchi Yusuke , Shibata H. , Uchida Y. , Huang Xin Sheng , Ono Masao , Okayasu Satoru , Mashimo Tsutomu
Published: March 2009

In this study, we investigate the crystalline states and conditions for the
grain-refinement of Bi70Sb30 (at.%) alloy. It was considered under an ultra strong gravity field, the
crystals were fine-grained from the primary grain sizes of several mm to several tens of mm, and
the crystal growth followed with formation of graded-composition structure due to sedimentation
of atoms along the direction of gravity. It was found that for the crystal-grain refinement in
Bi70Sb30 alloy the minimum gravitational field and the minimum time duration were at least
160,000 G and 10 hours, respectively at about 200 °C.
On the Forming of Metallic Parts through Electromagnetic and Electrohydraulic Processing
Authors: Priem Didier , Marya Surendar , Racineux Guillaume
Published: March 2009

Forming of metallic parts by the application of high intensity transitory magnetic pulses
or shock waves is a challenge task from industrial perspectives as this offers extended scope of
forming highly precise parts that result from material behavior at high deformation rates.
Electromagnetic forming requires that the part must be intrinsically very conducting. The electrohydraulic
forming is exempt from this material constraint as the deformation is generated by a shock
wave in a fluid through electric discharge in between the electrodes. The application of a static
pressure during forming is used to reduce the discharge energy for a given deformation. Work has
been conducted to form different parts through these two techniques involving aluminum, copper
and steels. The paper presents the technical obstacles still facing the electromagnetic techniques and
gives examples of formed parts and joints in relation with microstructures.
Effect of Scandium Addition on Aging Behavior of 6061 Aluminum Alloy
Authors: Nakamura Takahiko , Matsuo Tsukasa , Ikeda Masahiko , Komatsu Shinya
Published: March 2009

It has been reported that scandium addition improved various properties of aluminum
alloys. However, present authors can not find any reports about the addition of Sc to 6000 series
alloys. In this study, Sc was added to 6061 alloy and various effects of the Sc addition on aging
behavior were examined, comparing with Al-Sc binary alloy. In the STQ state, resistivity at 77K,
ρD77, of 0.2%Sc added alloy (6061+Sc) was about 2.0n-m higher than the alloy of no addition
(6061). The ρD77 increased in initial stage of isothermal aging up to 473K, then decreased. Though
ρD77 of binary Al-0.176%Sc alloy began to decrease from 1.8Ms at 448K and 18ks at 523K, excess
decrease in ρD77 of 6061+Sc corresponding to precipitation of Sc compounds was not clear. Peak
value of the HV0.1 was decreased and peak aging time delayed by the Sc addition in aging up to
498K. However, softening by overaging was retarded by the Sc addition. These effects of the Sc
addition are considered to come from vacancy trap by solute Sc atoms or interface between particles
of Sc compound and matrix acting as vacancy sinks.
Effects of Cooling Rate and Direct Hot Deformation Conditions after Solidification on the Austenitic Microstructure Evolved by Simulated Strip Casting and Thin Slab Casting Processes in HSLA Steels
Authors: Hotta S. , Murakami Taichi , Narushima Takayuki , Iguchi Yasutaka , Ouchi Chiaki
Published: March 2009

Currently new continuous casting processes such as thin slab caster or strip casting are
industrialized or under developing in the world steel makers. In these casting processes, cooling rate
after solidification becomes much faster compared with thick slab caster, and hot rolling mill
connected directly with casting machine tends to be installed. The present study was conducted to
investigate variations of austenitic grain size and micro segregation with cooling rate after
solidification and also direct hot deformation conditions in austenite immediately after solidification
in HSLA steels. HSLA steels were 0.15%C-0.25%Si-1.50%Mn, 0.028%Nb and
0.028%Nb-0.015%Ti with the same basic compositions. A hot working simulator of
THERMECMASTER-Z was used, and the center part of tensile specimen set up in this machine
was partially or fully levitation-melted by induction heating under argon gas atmosphere. After
melting, specimens were cooled at cooling rate from 0.4K/s to 40K/s, and this range covered
cooling rates after solidification in heavy thick slab caster and strip casting. Direct hot tensile
straining in austenite after solidification was conducted at strain rates from 1.4×10-3s-1 to 2.6s-1,
corresponding to an extracting speed in a respective caster. The increase of cooling rate refined
continuously as cast austenitic grain size, and it was enhanced in micro alloyed steels. Micro
segregation such as Mn was improved by faster cooling. Direct straining after solidification
markedly refined austenitic grain size through dynamic or static recrystallization occurring
depending on strain rate.
Transient Cooling of a Hot Steel Plate by an Inclined Bottom Jet
Authors: Chester N.L. , Wells Mary A. , Prodanovic V. , Militzer Matthias
Published: March 2009

Controlled cooling on the runout table is a crucial component in the production of
highly tailored steels since it has a strong influence on the final mechanical properties. High
efficiency heat transfer in impinging jet cooling makes this an important method for heat transfer
enhancement. The purpose of this study is to develop an experimental database for modelling of
boiling heat transfer for bottom jet impingement that occurs during runout table cooling in a steel
mill. Experiments have been carried out on a pilot scale runout table using stationary plates, with
focus on the effect of water flow rate and nozzle inclination to the overall heat transfer rates.
Volumetric flow rates and inclination angles are in the range of 35-55 l/min and 0-30º,
respectively. Temperatures on the test plates are measured internally very close to the surface
during cooling for the purpose of reducing thermal lag and receiving better data responsiveness.
These measurements are taken at the impingement point and several streamwise distances from the
impingement point. From the above measurements transient cooling data on the hot steel plate by
bottom jet impingement has been analysed.
Effects of Thermo-Mechanical Process on the Microstructure and Mechanical Properties of Low Carbon HSLA Steels
Authors: Kang J.S. , Huang Y. , Lee C.W. , Park Chan Gyung
Published: March 2009

Effects of deformation at austenite region and cooling rate on the microstructure and
mechanical properties of low carbon (0.06 wt. % C) high strength low alloy steels have been
investigated. Average grain size decreased and polygonal ferrite transformation promoted with
increasing deformation amount at austenite region due to increase of ferrite nucleation site.
Microstructure was also influenced by cooling rate resulting in the development of a mixture of fine
polygonal ferrite and acicular ferrite at 10°C/s cooling rate.
Discontinuous yielding occurred in highly deformed specimen due to the formation of polygonal
ferrite. However, small grain size of highly deformed specimen caused lower ductile-to-brittle
transition temperature than slightly deformed specimen.