bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and Characteristics of Monodispersed MFe2O4 Nanoparticles for Applications in Biomedicine
Authors: Park S.I. , Kim J.H. , Kim Cheol Gi , Kim Chong Oh
Published: March 2009

The monodispersed hydrophilic magnetic fluids with nanometric MO·ferrite (M=Cu, Co, Ca, Ni) particles were prepared by the sonochemical method. The substituted amounts of M elements were analyzed with different x values by ICP-AES quantitatively for MxFe3-xO4 particles.
Texture and Microstructure Evolution of Gold Sheet during Deformation and Annealing
Authors: Cho Jae Hyung , Choi Shi Hoon , Oh Kyu Hwan
Published: March 2009

Texture and microstructure of gold sheet were investigated during deformation and subsequent annealing. The Brass, S and Copper (β-fiber) orientations are closely connected together in the deformed microstructure. Recrystallization texture also was examined during isothermal annealing at 500°C with reduction in area. Initial rolling textures with rotated cube and β-fiber resulted in the cube and recrystallized β-fiber orientations after annealing. A two dimensional Monte Carlo (MC) method was used to simulate primary recrystallization in gold sheet. A function of boundary misorientation was introduced to consider anisotropic properties of grain boundary energy and mobility. Stored energy associated with orientations in the deformed grains was evaluated by reconstructing of data measured using electron back-scattered diffraction (EBSD). The nucleation at an initial stage of recrystallization was found at the high angle grain boundaries (HAGBs) and grain interiors. The main texture components obtained by the simulation were similar to those obtained experimentally except cube component.
Recrystallization Behavior of the Nickel-Based ODS Superalloy PM 1000
Authors: Sandim Hugo Ricardo Zschommler , Hayama Alexandra O.F. , Raabe Dierk
Published: March 2009

PM 1000 is a nickel-based oxide dispersion strengthened (ODS) superalloy used for
high-temperature applications. The primary recrystallization of a <100>-fiber textured coarsegrained
oxide dispersion strengthened nickel-based superalloy (PM 1000) has been investigated.
The annealing behavior of this alloy is quite complex. Even when annealing is performed at high
homologous temperatures (e.g. 0.9 Tm, Tm is the melting point), recrystallization is partial. In order
to understand such a behavior, the microstructure of specimens in both the as-received, deformed,
and annealed conditions has been imaged in detail using scanning electron microscopy (SEM),
transmission electron microscopy (TEM), and high-resolution electron backscatter diffraction
(EBSD). In the annealed state we observe a significant volume fraction of tiny crystals in the
interior of the recovered grains. These tiny grains are elongated and grow mostly along the existing
low angle dislocation boundaries (anisotropic growth). In the present paper we propose a twinningassisted
nucleation mechanism to clarify their origin during recrystallization.
The Role of Zirconium Additions in Recrystallization of Aluminum Alloys
Authors: Weiland Hasso , Cheong Soon Wuk
Published: March 2009

Control of grain size during recrystallization of aluminum alloys is critical when tailoring material properties for structural applications. Most commonly the grain size is controlled by adding alloying elements which form second phases during homogenization heat treatments small enough to impose a Zener drag on the grain boundary mobility. These phases are known as dispersoids and are in the 10 to 200 nm in diameter range. In Al-Zn alloys, zirconium has been successfully used in controlling the degree of recrystallization after solution heat treatments. It is commonly understood that the Al3Zr dispersoids of about 20 nm in diameter present in the microstructure are the key features affecting grain boundary mobility. With the success of controlling recrystallization in Al- Zn alloys, zirconium has been added to other alloy systems, such as Al-Cu-Mn, and a similar retarding effect in recrystallization kinetics has been observed as seen in the Al-Zn systems. However, in Al-Cu-Mn alloys, zirconium bearing dispersoids are not observable in the microstructure. Consequently, additional microstructural effects such as solute drag need to be considered to explain the experimental observations. In this paper, the role of zirconium additions in aluminum alloys will be summarized.
Influence of Thermal Condition of ECAP on Microstructure Evolution in Low Carbon Steel
Authors: Zrník Jozef , Dobatkin Sergey V. , Kraus Libor
Published: March 2009

Commercial low carbon steel AISI 1010 was subjected to Equal Angular Channel Pressing (ECAP) at different temperatures. The paper describes the refinement of the coarse grained ferrite microstructure to submicrocrystalline range by large plastic strain. The steel was deformed in an ECAP tool with a channel angle φ = 90°, at different temperature in the ranging between 150 – 300°C. The number of passes at each temperature was N = 3. Optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to study the formation of substructure and ultrafine grains in the deformed specimens. The TEM study reveals that at the lowest ECAP temperature of 150°C extensively elongated ferrite grains with dense dislocation network dominate in the structure. The randomly scattered polygonized subgrains have been observed. The activation of dynamic recovery process, even at the lowest temperature of equal channel pressing, contributed to the formation of individual polygonized grains. As the temperature of ECAP processing was increased the process of dynamic polygonization and recrystallization occurred more effectively and the submicrocrystalline structure was formed by sectioning of elongated ferrite grains. The formation of such predominant submicrocrystalline structure resulted in strength increase of the low carbon steel.
Fatigue Strength of Friction Stir Welded Aluminum Alloy Joints
Authors: Qu Hong Qiu , Tsujikawa Masato , Chung Sung Wook , Oki Sachio , Higashi Kenji
Published: March 2009

Strength of Al5083-O FSW joints was evaluated, in relation to FSW conditions. Static
strength of the joints was found to be enough because base metal fracture occurred in the tensile
tests of joints for some FSW conditions. However, the fatigue strength of those joints with fine
static strength varied significantly. For example, in tensile strength of joints with the FSW
condition with tool rotation: 800 rpm- welding speed: 100 mm/min (800-100), 800 rpm-200
mm/min (800-200) and 500 rpm- 100 mm/min (500-100), each condition of FSW joint efficiency
were all hundred percent. In contrast, joint efficiency for fatigue strength varied from 75% for
500-100 to 31% for 800-200. Crack path in fatigue test was always initiated at the center of back
surface of FSW weld zone, and propagated through stir zone. The variance of fatigue strength is
believed to be attributed to the stirred condition at back surface.
Grain-Boundary Structure and Phase-Transformation Mechanism in Yttria-Stabilized Tetragonal Zirconia Polycrystal
Authors: Matsui Koji , Yoshida Hidehiro , Ikuhara Yuichi
Published: March 2009

The microstructures in 3 mol% Y2O3-stabilized tetragonal zirconia polycrystal (Y-TZP) sintered at 1100°-1650°C were investigated to clarify cubic-formation and grain-growth mechanisms. The cubic phase in Y-TZP appeared at 1300°C and its mass fraction increased with increasing sintering temperature. High-resolution transmission electron microscopy (HRTEM) and nanoprobe X-ray energy dispersive spectroscopy (EDS) measurements revealed that no amorphous layer existed along the grain-boundary faces in Y-TZP, and Y3+ ions segregated not only along the tetragonal-tetragonal phase boundaries but also along tetragonal-cubic phase boundaries. Scanning transmission electron microscopy (STEM) and nanoprobe EDS measurements revealed that the Y3+ ion distribution was nearly homogeneous up to 1300°C, but cubic phase regions with high Y3+ ion concentration clearly formed inside grains at 1500°C. These results indicate that cubic phase regions are formed from the grain boundaries and/or the multiple junctions in which Y3+ ions segregated. We termed such a new diffusive transformation phenomenon “grain boundary segregation-induced phase transformation (GBSIPT)”. The grain-growth mechanism is controlled by the solute-drag effect of Y3+ ions segregating along the grain boundary.
Effect of Fast Annealing on Microstructure and Mechanical Properties of Non-Oriented Al-Si Low C Electrical Steels
Authors: Gutiérrez C. Emmanuel , Salinas-Rodríguez Armando , Nava-Vázquez Enrique
Published: March 2009

The effects of heating rate and annealing temperature on the microstructure and mechanical properties of cold rolled Al-Si, low C non-oriented electrical steels are investigated using SEM metallography and uniaxial tensile tests. The experimental results show that short term annealing at temperatures up to 850 °C result in microstructures consisting of recrystallized ferrite grains with sizes similar to those observed in industrial semi-processed strips subjected to long term batch annealing treatments. Within the temperature range investigated, the grain size increases and the 0.2% offset yield strength decreases with increasing temperature. It was observed that the rate of change of grain size with increasing temperature increases when annealing is performed at temperatures greater than Ac1 (~870 °C). This effect is attributed to Fe3C dissolution and rapid C segregation to austenite for annealing temperatures within the ferrite+austenite phase field. This leads to faster ferrite growth and formation of pearlite when the steel is finally cooled to room temperature. The presence of pearlite at room temperature decreases the ductility of samples annealed at T > Ac1.
Processing and Mechanical Properties of Porous Titanium-Niobium Shape Memory Alloy for Biomedical Applications
Authors: Xiong Jian Yu , Li Yun Cang , Yamada Yasuo , Hodgson Peter , Wen Cui E
Published: March 2009

Ti-26 at.%Nb (hereafter Ti-26Nb) alloy foams were fabricated by space-holder sintering process. The porous structures of the foams were characterized by scanning electron microscopy (SEM). The mechanical properties of the Ti-26Nb foam samples were investigated using compressive test. Results indicate that mechanical properties of Ti-26Nb foam samples are influenced by foam porosity. The plateau stresses and elastic moduli of the foams under compression decrease with the increase of their porosities. The plateau stresses and elastic moduli are measured to be from 10~200 MPa and 0.4~5.0 GPa for the Ti-26Nb foam samples with porosities ranged from 80~50 %, respectively.
First-Principles Calculation of Interaction Energies between Solutes and/or Vacancies for Predicting Atomistic Behaviors of Microalloying Elements in Aluminum Alloys
Authors: Shoichi Hirosawa , Nakamura Fumishige , Sato Tatsuo
Published: March 2009

The atomistic behaviors of microalloying elements during phase decomposition of Al-
Cu-Mg, Al-Zn-Mg and Al-Mg-Si alloys have been systematically predicted in terms of two-body
interaction energies between solutes and/or vacancies. The utilized first-principles calculation based
on generalized gradient approximation (GGA) and full-potential Korringa-Kohn-Rostoker (FPKKR)
Green’s function method accurately estimated such fundamental energies in good agreement
with experimentally reported behaviors: e.g. vacancy-trapping model, vacancy-sink model and
nanocluster assist processing. The proposed interaction energy maps (IE maps), in which the
estimated interaction energies are plotted along the rows of the periodic table, are quite useful for
designing new aluminum alloys with microalloying elements.
Underwater Explosive Welding of Thin Magnesium Plate onto some Metal Plates
Authors: Mori Akihisa , Hokamoto Kazuyuki , Fujita Masahiro
Published: March 2009

Explosive welding of a thin magnesium plate onto some metal plates was performed by
using underwater explosive welding technique developed by some of the authors. The experimental
results show that the wavy interface which is typically found in the well-bonded clad was observed.
The welding condition is discussed using the welding window based on the numerically simulated
results using AUTODYN-2D code.
Advanced Materials Synthesis and Microstructural Characterization Using Explosive at Sojo University
Authors: Ii Seiichiro , Kira Akio , Tomoshige Ryuichi , Fujita Masahiro
Published: March 2009

In the research center for advances in impact engineering established in Sojo university, advanced
materials have been synthesized by using shock wave and their microstructure has been investigated.
An extremely high shock pressure and a dynamic hot compaction technique were developed, and
the synthesis of the advanced materials and composites was succeeded. Transmission electron
microscopy observations revealed unique microstructures of such materials obtained by our original
advanced technique.
Development of a Large Diameter Diaphragmless Shock Tube for Gas-Dynamic Laser Studies
Authors: da S. Rego I. , Sato K.N. , Kugimiya S. , Aoki T. , Miyoshi Y. , Ando T. , Goto K. , Sakamoto M.
Published: March 2009

This paper reports on the design and performance of a large diameter diaphragmless shock
tube that has been recently developed in order to experimentally study various basic characteristics of
the gas-dynamic laser (GDL). The main engineering element of the shock tube is a diaphragm-like
sliding piston (in place of a rupturing diaphragm) by which normal shock waves are formed. The role
of such a structure in generating repeatable shock waves is discussed. The shock tube performs in
good accordance with the simple shock tube theory, as has been verified so far by experiments with
some conventional lasing gases (gaseous mixtures of CO2 and N2 and those diluted with an excess of
He) at shock wave Mach numbers ranging from 1 to 5. Recent results of the stagnation conditions
achieved in the shock tube with application to GDL experiments are included as well.
Optimum Material Design of Metal-Ceramic Hybrid Functionally Graded Composite
Authors: Choi Joo Hyoung , Cho Jin Rae
Published: March 2009

In this paper, an efficient optimum material design technique is introduced for hybrid
designing of dual-phase heat-resisting functionally graded composites. The graded region is divided
into a finite number of homogeneous material layers in order to reduce the total design variables. The
discrete optimum volume fractions are sought by making use of the interior penalty method and the
finite difference sensitivity scheme. A linear interpolation technique is adopted to make the final
optimum volume fraction distribution be continuous. The validity of the proposed optimization
technique is examined through the illustrative numerical experiment.
Experimental Analysis in Lithium Niobate CMP for Room Temperature Bonding
Authors: Cho Han Chul , Jeong Suk Hoon , Park Jae Hong , Lee Ho Jun , Oh Ji Heon , Kim Hyoung Jae , Jeong Hae Do
Published: March 2009

Lithium niobate (LN, LiNbO3) is a kind of artificial crystal with piezoelectricity, pyroelectricity and ferroelectricity, which has been widely used in electron components. The large difference in thermal expansion coefficients between Si and LN causes a serious thermal stress during the thermal-pressure bonding process. Therefore room temperature bonding would be the best candidate to make strong and stress-free interface between Si and LN. However, room temperature bonding requires lower surface roughness (Ra<2nm) and lower defects on the LN wafer surface than those of thermal bonding. Chemical mechanical polishing (CMP) process helps LN to obtain the high quality surface and thin wafer suited in room temperature bonding. The LN wafer was polished using colloidal silica slurry, resulting in high material removal rate (MRR) and fine surface quality under the condition of low pH, high abrasive concentration and low flow rate. The polishing mechanism of LN was discussed by mechanical, chemical and thermal analysis.
Surface Roughness Control of Zirconia Films Using a Novel Photoresponsive Precursor Molecule for Improving its Photocatalytic Activity
Authors: Nishizawa Kaori , Miki Takeshi , Watanabe Eiji , Taoda Hiroshi
Published: March 2009

A novel photoresponsive zirconia (ZrO2) precursor solution was prepared using
zirconium tetra-n-butoxide, 4-(phenylazo)benzoic acid and ethyleneglycol monomethylether. Two
kinds of ZrO2 films were prepared using the photoresponsive ZrO2 precursor solution and by
dip-coating while applying an electric field to the substrates: one was the film prepared with
ultraviolet (UV) irradiation to the solution and as-deposited films; the other was the film prepared
without UV irradiation. It was found that the surface roughness of films was greatly changed by UV
irradiation. Furthermore, the photocatalytic activity of the rough film was greater than that of the
smooth film.
Optical Property of Hybrid Material Including Crystalline in Amorphous Matrix
Authors: Lee Kyu Ho , Kim Young Seok , Kim Tae Ho , Jung Young Joon , Chin H. J. , Ryu Bong Ki
Published: March 2009

This paper presents results and observations obtained from a study of crystallization effect on optical property by doping Sm2O3 in amorphous material. The heat treatments, according to Differential Thermal Analyzer (DTA) results, have been performed in order to generate crystallization of amorphous material. The crystalline phase has been analyzed by X-Ray Diffractor (XRD). In this work, we have observed the emission intensity changes by increasing the concentration of Sm3+ ions up to 1.0mol%. As a result, we have confirmed the solubility of RE dopant in this composition glass by comparing the emission intensity at three strong emission bands [4G5/2-6H5/2 (564 nm), 4G5/2-6H7/2 (602 nm) and 4G5/2-6H9/2 (647 nm)]. Beside, the up-conversion of photoluminescence by the optimum crystalline size of host matrix has been shown by Fluorimeter data. In conclusion, we have estimated the effect of crystalline on optical property in amorphous matrix from this research.
Numerical Simulation of Autogenous Shrinkage of Eco-Friendly Blended Portland Cements Using a Multi-Component Hydration Model
Authors: Wang Xiao Yong , Lee Han Seung , Lim Seung Min
Published: March 2009

Fly ash and granulated blast-furnace slag, which are used as blends of Portland cement, are
waste materials produced in electric and energy industry. Due to excellent durability, low heat of
hydration, energy-saving, resource-conserving, and generally less expensive than ordinary Portland
cement, blends Portland cements is used increasingly in construction industry. Both ecology benefit
and economic benefit can be achieved by using blended Portland cement.
Addition of blended components to cement, especially such as fly ash or silica fume, will lead to
a densification of the microstructure. The autogenous shrinkage deformation will increase and the
following autogenous shrinkage crack will do harm to durability of concrete structure. In this paper,
based on the multi-component hydration model, a numerical program is built to predict autogenous
shrinkage of ordinary Portland cement and blended Portland cement. The numerical program
considers the influence of water to cement ratio, curing temperature, particle size distribution, cement
mineral components on hydration process and autogenous shrinkage. The prediction result agrees
well with experiment result.
Effect of Different Upper Side Types of Plaster Molds on the Pore Formation of Al Foams via Upward Foaming Method
Authors: Jeong M. J. , Seo Chang Hwan , Song Yeong Hwan , Kang K.J. , Hur Bo Young
Published: March 2009

Fabrication of Aluminum foam with near net shape has been investigated by powder metallurgy method and conventional pouring method. PM method is good for fabrication of near net shape foam, but it needs high cost compared with pouring method. More cost-effective methods are needed to make near net shape al foam to be applied various field. Therefore, novel method for fabrication Al foam was researched in this paper. In order to prepare near shape Al foams with homogeneous pore structures, the so-called upward foaming method was designed and applied. By using this method, two kinds of molds were designed, one is stainless mold used for melting and foaming Al and another is the plaster mold with near net shape. The fabrication procedures of near net shape Al foam are as following: (1) a quantity of Al ingot was melted in the stainless mold; (2) Ca particles was added in the Al melt to increase its viscosity; (3) TiH2 was introduced in the thickened Al melt to make melt being foamed; (4) the plaster mold was put on the stainless steel one to make enlarging Al melt foam fill with the plaster one; (4) the plaster mold was removed and was cooled. In this study, in order to get near net Al foam with relative good pore structures, the plaster molds were designed with three different upside styles and their effects on the pore structures (pore size, porosity and cell wall thickness) of Al foams were investigated. The results showed that the Al foam had the relative good pore structures when the plaster mold with a void was applied.
Characterization of Anodized TiO2 for Hydrogen Evolution in Enzymatic PEC System
Authors: Yoon Jae Kyung , Bae Sang Hyun , Ha Jin Wook , Joo Hyun Ku
Published: March 2009

In this study, an anodized TiO2 electrode (ATE) on a titanium foil was prepared and used as a photoanode in an enzymatic photoelectrochemical system to split water into oxygen and hydrogen. The effect of applied voltage when anodized, thickness of foil, electrolytes, annealing temperature, and species of cathode was investigated. The optimum conditions were obtained such as 0.25 mm foil thickness, 20V of applied voltage in 0.5 vol% of hydrofluoric acid, and 650 oC of annealing temperature. The samples with higher activities had similar X-ray diffraction (XRD) patterns, clearly indicating that the samples showing the highest evolution rate were composed of both anatase and rutile, while those showing a lower evolution rate were made of either anatase or rutile. Increasing the intensity of the irradiated light caused a remarkable enhancement in the rate of hydrogen production up to 153 μmol/(hr×cm2) under light intensity of 146 mW/cm2.
Synthesis of MgO Thin Film Deposited on Soda Lime Glass by Sol-Gel Process
Authors: Shin Dae Yong , Kim Kyung Nam
Published: March 2009

MgO thin film was deposited on soda lime glass substrate by sol-gel process. MgO thin film with the (200) preferred orientation were prepared by heat-treated at 300~500°C for 10 min. The crystallization, microstructure and electrical properties with various parameters of MgO thin films were investigated. Consequently, it was shows that the (200) preferred orientation of MgO thin film could be obtained as the heating temperature was increased. At heating temperature of 500°C, MgO thin film was composed of columnar crystals with a size of 120 nm. The dielectric constant of the (200) preferred orientation of MgO thin film at 1 kHz without the electric field was 7.2, with a dissipation factor of 4%. When the electric field was increased, the dielectric constant approaches to 7.9 with the dissipation factor of 2.1%. The refractive index of MgO thin film depended on the film thickness. The refractive index of 250 nm thickness was 1.70.
Structural and Magnetic Characterization of Polyaniline Composite Films
Authors: Aphesteguy Juan C. , Jacobo Silvia E. , López Antón Ricardo , Kurlyandskaya G.V.
Published: March 2009

In this work a novel approach for the preparation of Fe3O4/PANI (polyaniline) thin film composite containing magnetic nanoparticles is presented. Magnetite (Fe3O4) nanoparticles have been coated by PANI and the PANI chains have been doped by 10-camphorsulfonic acid (CSA). The doped composite is soluble in common organic solvents. Thin films of composites of polyaniline (PANI) were casted from m-cresol. Several characterization techniques were employed in order to determine composition, structure and magnetic properties of the nanocomposite film (Xray diffraction, transmission electron microscopy, TEM, Scanning electron microscopy, SEM, and optical microscopy). The magnetization data were obtained from M(H) hysteresis loops and zero field cooling – field cooling, ZFC-FC. Magnetic measurements evidence a ferromagnetic behaviour of the obtained composite, at room temperature with saturation magnetization of about 3.4 emu/g and coercivity of 42 Oe. The temperature dependences of the conductivity of the films follows the         = − 1 / 2 ( ) exp T T To o σ σ law, which has been explained within the framework of the onedimensional variable-range-hoping (1D-VRH) model. Application of 1T magnetic field increases the resistivity of the film and the temperature slope dependence.
A New Approach of Synthesis of Al2O3 Nanofluid
Authors: Chang Ho , Kao Mu Jung , Chang Yu Chun , Huang Dao Yi
Published: March 2009

The purpose of this paper is to research and develop a new nanofluid synthesis system that
uses plasma arc as heat source to fabricate nanofluid having high suspension stability. This system uses
high temperature produced by plasma arc system to cause transient vaporization to metal, which is then
followed by the induction of vaporized metallic gas into the collection piping by the induction system.
At the same time, it mixes thoroughly with the pre-condensed deionized water, and the mixture is then
underwent a rapid cooling process. Because of low temperature, the metallic gas condenses into
nanoparticles, which is finally stored in the collection tank in the form of nanofluid. This paper
discusses the influence of working current towards the fabricated Al2O3 nanoparticle. Also, based on
the Al2O3nanofluid having different pH values, it analyzes into the suspension stability of its Zeta
potential value. Furthermore, it investigates into the absorption properties of Al2O3
nanofluid towards
UV/Vis. Besides, as known from the experimental result of the fuel calorific test, when the weight
concentration of the Al2O3
nanofluids that is produced by a better fabrication is 3%, it explores into its
good combustion efficiency towards 92 unleaded gas.
Novel Fabrication Method of Nanofluid Having Good Roundness and High Suspension Stability
Authors: Chang Ho , Kao Mu Jung , Lin Shih Chieh , Huang Dao Yi
Published: March 2009

In this study, the author uses the self-developed submerged arc nanofluid synthesis system to
fabricate TiO2
nanofluids. This system uses the energy produced by arc discharge to melt and
vaporize matallic polarities under a vacuum condition. The vaporized metal is cooled rapidly
inside a low-temperature dielectric liquid, forming nanoparticles that are evenly distributed
inside the dielectic liquid. Experiment proves that the roundness of the fabricated
TiO2nanoparticles are much better than those fabricated by aerosol methods. Also, the
fabricated nanofluid carries a high suspension stability. We uses X-ray absorption
spectroscopy to analyze their electronic structure of TiO2
nanofluid. Besides, by measuring
the Zeta potential of TiO2
nanofluid having different pH values, it investigates into the
suspension stability of the TiO2nanofluid. In order to verify the applicability of the
TiO2nanofluid, this study also analyzes and compares the rheology properties of the nanofluid
having different average particle sizes as well as their reaction towards light absorption.
Temperature Dependence of Residual Stress Gradients in Shot-Peened Steel Coated with CrN
Authors: Martinschitz Klaus J. , Kirchlechner C. , Daniel R. , Maier G. , Mitterer C. , Keckes Jozef
Published: March 2009

A temperature behaviour of residual stresses in shot-peened steel coated with 3m CrN is
characterized using in-situ energy dispersive synchrotron X-ray diffraction performed in the
temperature range of 25-800°C. The samples are thermally cycled and the development of volumeaveraged
residual stresses in the coating and residual stress depth gradients in the steel is
characterized. The results reveal complex changes of stresses in CrN and in the substrate. The
annealing results in the removal of stress gradients in the steel which starts at the temperature of
about 600°C. After cooling down, there are no stresses detected in the steel. The temperature
dependence of stresses in CrN is very complex and indicates the presence of phenomena like an
annealing of intrinsic stresses about the deposition temperature of 350°C, a formation and a closing
of micro-cracks in the tensile region and finally a stress relaxation of approximately 500 MPa after
the cooling down. The presented approach allows a complex characterization of thermo-mechanical
processes in coating-substrate composites and opens the possibility to understand phenomena
related to the thermal fatigue of coated tools.
In Situ Neutron Diffraction Studies of the Pseudoelastic-Like Behaviour of Hydrostatically Extruded Mg-Al-Zn Alloy
Authors: Muránsky Ondrej , Carr David G. , Šittner Petr , Oliver E.C. , Dobroň P.
Published: March 2009

In-situ neutron diffraction has been used to study the pseudoelastic-like behaviour of
hydrostatically extruded AZ31 magnesium alloy during stress-strain cycles in compression and
tension along the extrusion direction. It has been confirmed that the activation of reversal twinning
processes during unloading is responsible for the macroscopically observed hysteresis effect.
Moreover, neutron diffraction data reveals the existence of high tensile stresses in grains which
have just experienced significant twinning activity prior to the start of the unload cycle. It is thus
proposed that this tensile stresses provides the necessary driving force for the activation of
untwinning in already twinned grains.
Two-Dimensional Mapping of Crack-Face Bridging Stresses in Alumina Using Synchrotron Micro X-Ray Beam
Authors: Sakaida Yoshihisa , Mori Shotaro
Published: March 2009

In order to understand an effect of crack-face bridging stress field of alumina ceramics on
its fracture toughness, local residual stress distribution due to crack face grain bridging behind the
crack tip was measured using synchrotron x-ray beam at SPring-8 in Japan. The SEPB (Single Edge
Precracked Beam) specimens of two types of polycrystalline Al2O3 were used for stress measurement;
one was pressureless sintered Al2O3 (AL1) and the other was hot-press sintered Al2O3 (TAL).
Pop-in precracks were introduced by bridge-indentation method. Before residual stress mapping,
the SEPB specimens were unloaded from a constant applied load to zero using four points bending
device. Two-dimensional residual stress field was mapped by scanning a micro X-ray beam of
50×50 μm2 with the scanning interval of 12.5 or 25 μm. As a result, in the case of AL1 having conventional
fracture toughness and strength, the compressive residual stresses due to crack-face
bridging were only observed in the close vicinity of crack tip. On the other hand, in the case of TAL
having higher fracture toughness and strength, the compressive residual stresses were widely distributed
behind the crack tip. Larger compressive stress was locally generated along the crack path
at interlocked grains. The compressive bridging stresses distributed behind the crack tip were found
to enlarge with a decrease in the crack opening displacement against a constant applied stress intensity
factor, Kapp. It was concluded that the difference in residual stress fields behind crack tip was
attributed to the differences in its microstructure and microcrack propagation behavior, such as deflections
and interlocked grains.
Measurement of Strain Distribution around Weld Zone for Railway Carbody Structure Using High-Energy Synchrotron Radiation
Authors: Matsumoto Keisuke , Shobu Takahisa , Akiniwa Yoshiaki , Yagi Tsuyoshi , Yamamoto Masataka
Published: March 2009

The railway carbody structure for commuter and suburban train services in Japan is often
made of austenitic stainless steel, which is used in the form of thin metal sheets manufactured by cold
rolling. Spot welding and laser welding at lapped joints are used in the construction of such carbodies,
but it is difficult to observe the strain distribution around these weld zones, which represent the
critical area of the body structure’s strength. The objective of this study is to ascertain the strain
distribution in the stainless steel around the weld zone of the carbody structure. To enable observation
of this distribution, a strain scanning method using high-energy synchrotron radiation was applied
to the strain measurement of austenitic stainless steel. The transmission method was applied in
order to observe the internal weld zone. Using this method, we can measure the strain distribution
from the surface to the inside of the weld zone. A lapped joint specimen, prepared by welding
2-mm-thick plates using the laser welding method, was used for measurement. Austenitic stainless
steel generally poses problems in the measurement of strain due to its coarse grain and crystal texture.
The gage volume in this measurement had a width of 3 mm and a height of 0.15 mm. The measurement
provides the strain distribution of both residual strain and strain under loading, and the
results obtained successfully show the distribution of strain in the weld zone. In addition, the differing
tendency between the distribution of residual strain and that of strain under loading is clarified.
The full width at half maximum (FWHM) value shows a difference between the tendency of the
measured value of the weld zone and that of the base material.
Microstructure and Residual Stresses in Dissimilar Mg-Al-Zn-Alloy Single Overlap Laser Beam Welds
Authors: Coelho R.S. , Kostka A. , Pinto Haroldo , Riekehr Stefan , Koçak Mustafa , Pyzalla Anke
Published: March 2009

Microstructure, hardness and residual stresses of the laser beam overlap welds between AZ31B
sheets and AZ31, AZ61 and AZ80 extruded profiles are investigated using microscopy and X-ray
diffraction. The result of the investigations reveal that weld microstructure, the size of the HAZ,
precipitate density and the maximum compressive residual stress values depend strongly on the Al
content of the weld zone of two Mg-alloys.
Study of Residual Stress Distribution in a Stainless Steel Bead-on-Plate Simulation Benchmark Sample
Authors: Ganguly S. , Pratihar S. , Fitzpatrick Michael E. , Edwards Lyndon
Published: March 2009

This paper summarizes the results of a neutron diffraction study of a single weld bead on
a rectangular austenitic stainless steel plate. The measurement was carried out at SALSA, the
engineering strain scanner at the ILL, Grenoble, France. The work has been carried out under the
European NET project, and is a round robin exercise of residual stress simulation and validation
benchmark in a stainless steel bead-on-plate (BOP) weldment. A monochromatic beam of
wavelength 1.494 Å was used and the lattice spacing of {311} crystallographic plane was
measured. The principal strain measured in the plate was corrected by measuring small cube sample
of 3×3×3 mm3 as stress free reference. The measured strain was then used to calculate the principal
stress distribution. Finally, the measured strain was compared with the strain measured in a similar
specimen in a pulsed neutron source by the time-of-flight (TOF) technique.
Residual Stresses in High Strength, Thick Section Steel Welds
Authors: Pearce Susan V. , Linton Valerie
Published: March 2009

The conservative assumption of residual stress in highly restrained steel structures can
lead to unnecessary repairs of defects in welded joints. This applies particularly with respect to high
restraint, high yield strength thick sections welds because the assumption of yield strength residual
stress is used in integrity assessments. By analysing the stress within components both before and
after welding it is anticipated that a greater understanding of the residual stress field as a product of
both the welding residual stress and the pre-welding residual stress can be made. This paper
discusses a series of experiments designed to build up such a model of the changing stress field
within a T-butt weld. Neutron strain scanning has been performed on unwelded flat and curved steel
sections and a curved T-butt weld. To complement this, surface X-ray measurements have been
carried out in order to gain a quantitative measure of the changing surface stress during welding and
sectioning. The findings were that welding stresses dominate close to the weld, bending stresses
dominate further from the weld.
Application of Neutron Diffraction Technique to Industrial Materials
Authors: Takahashi Shunichi , Sasaki Toshihiko , Sato Yukio , Iwafuchi Kengo , Suzuki Hiroshi , Morii Yukio , Kondo Yasuto , Monzen Ryoichi , Hirose Yukio
Published: March 2009

As an important industrial problem, the rolling contact fatigue damage is accumulated in
rails during the repeated passage of trains over the rails, and rail failures may occur from the cracks
grown in the rails. In order to prevent such rail failures, the estimation of the behavior of internal
rail cracks is required based on the exact engineering analysis model as well as conducting rail test
to search rail defects. The purposes of this paper are to apply the neutron stress measurement to rails,
and to obtain residual stress state in the rails for the above purpose. The rail samples used were
those that have been used in service line in Japan for about six years (222 million gross tons). The
neutron measurement was conducted using the Residual Stress Analyzer (RESA) of the Japan
Atomic Energy Agency (JAEA). The present measurement of stresses in rails by the neutron
diffraction method was the first attempt in Japan.
Numerical Simulation of Die-Casting Mold Filling Process by Using Fractional Step Method
Authors: Yang Jie , Ren Yu Xin , Xiong Shou Mei
Published: March 2009

In the numerical simulation of mold filling process, the calculation efficiency has been a
key point for practical applications due to the complexity and thin-section of die castings. In current
research work, a fractional step method was applied in the solution of the unsteady Navier-Stokes
equations, which can be implemented with a single solution to the momentum/pressure equations at
each time step. This method may avoid the decrease in efficiency induced by iteration. A water
analog system was designed and developed to simulate the die casting process. The flow patterns
were recorded by a high speed camera with a capturing rate of 500 frames per second. The simulation
results were consistent with the experimental ones. Besides, the fluid flow patterns of several
components were simulated by the fractional step and VOF algorithm, and the SOLA-VOF
algorithm respectively. The simulation results showed that the combination of the fractional step
method and VOF method can improve the computational efficiency to some extent in numerical
simulation of mold filling process.
Research on Heat Treatment Techniques and Structure Properties of CuNi2TiCrZr Alloy
Authors: Xu Yu Song , Wang Xiao Lian
Published: March 2009

To replace the heavily contaminative and long price CuCo2Be alloy, the titanium bronze
of no more than 3.5wt% alloying agents was introduced in this article, and its best techniques of
heat treatment and cold deformation were confirmed. The metallurgical structures and fracture
patterns were observed and analyzed respectively, and the microstructure was also surveyed by
TEM. Results showed that titanium bronze belonged to deposition strengthening, and the main
precipitated phase Ni3Ti distributed dispersedly in the group, whose size was about 20nm.
Compared to the CuCo2Be alloy, the grain size of titanium bronze is more sensitive to temperature.
So the titanium bronze can not be applied under overaging situation.
Study on Preparation of Ti Powder by Self-Propagating High-Temperature Synthesis (SHS) with Magnesiothermit Reductive Process
Authors: Zhang Peng Lin , Xia Tian Dong , Zhang Guo Dong , Yan Li Jing
Published: March 2009

The combustion process of Mg-TiO2 system was preliminarily investigated from three
aspects of thermodynamics, reaction kinetics and the technological parameters. The result indicates
that the adiabatic temperature of Mg-TiO2 system is between 2060K and 2140K because the major
existent modalities of TiO2 is the rutile and anatase, this meets the empirical criterion that the SHS
reaction will be self-sustaining; The solid-solid reaction occurs at about 767K; Ti powders can be
produced only when the ratio between Mg and TiO2 arrives at 2.9:1; The higher the vacuum, the
more complete the reaction; The combustion temperature arrives at its peak when the pressure of
green compact arrives at 250MPa; the velocity of the combustion wave increases with the
augmentation of the pressure of green compact. So the proper control of the technological
parameters can change the reaction temperature, reaction rate and the components of reaction
products.
A Cellular Automata Model for Dendrite Structure Simulation
Authors: Yu Liang , Wu Liu Shun , Li Liao Sha , Dong Yuan Chi
Published: March 2009

Dendrite structure in solidification process has been studied by many researchers for it’s
widely existence. In present work, a cellular automata model was proposed according to the basic
physical chemistry concepts, which was helpful for a better understanding of the dendrite crystal
growth and its physical chemistry mechanism. Two kinds of structures were considered in the model:
hexagonal and rectangle. The status of every site was set as 0 and 1 which represent non-solidified and
solidified state. Temperature field was simulated using finite difference method on the same mesh.
The states of sites were changed according to the overcooling condition only. The computer
simulation results showed that dendrite structure could be obtained under overcooling condition and
temperature field calculation only, the structure of the dendrite was decided by the geometry of the
model. The simulation resulted similar pattern as that obtained by experimental observation. The
present model suggested that there exist a very simple basic for the typical complex phenomena,
dendrite structure.
A Study on Fatigue Crack Propagation Properties Using the X-Ray Diffraction Method
Authors: Hossian Md. Anowar , Lim Man Bae , Huh Sun Chul , Park Won Jo
Published: March 2009

This study evaluated fatigue crack growth characteristics, Besides consider compressive
residual stress effect and verified the most suitable shot peening velocity. Fatigue crack growth
delay effect was compressive residual stress, but over peening did action projecting velocity that
accelerate fatigue crack growth rate. X-ray diffraction technique according to crack length
direction was applied to fatigue fractured surface. Fracture mechanics parameters could be
estimated by the measurement of X-ray parameters, and the fractography observation was
performed using a scanning electron microscope (SEM) for fatigue fracture surface. As the shot
peening velocity increases, striation width increased. The changes in X-ray material parameters
described above are directly related to the process of fatigue until the initiation of fatigue crack
and X-ray diffraction pattern is thought that failure prediction with stress distribution is possible.
A New Prediction Way to Shrinkage Cavity Formation for Ductile Iron Castings
Authors: Hou Hua , Zhang Guo Wei , Mao Hong Kui , Cheng Jun
Published: March 2009

Based on the solidification features of ductile iron and affecting
factors for ductile iron shrinkage defect, the model of the ductile iron solidification is
built and put forward a new defect predictive method EIECAM (Enclosed-Isolated
area Expansion and Contraction Accumulation Method) model to predict defect. in
DECAM, the liquid shrinkage, solidified shrinkage and graphitizing expansion during
solidification are computed dynamically in the enclosed-isolated area , and the effect
of graphite expansion on the wall movement is also accounted. Based on this method
end cover of QT500 ductile iron casting is simulated and made the defect predictive,
study its solidification process and the defect generation position, and make the
experimental identification on the defect. It is resulted that the method can be able to
predict the casting defect authentically.
Study on Temperature Distribution in Double Glow Discharge Zone
Authors: Zhang Ping Ze , He Zhi Yong , Zhang Gao Hui , Rong Xing Fu , Wu Hong Yan , Xu Zhong
Published: March 2009

This paper deals with the temperature measuring of the glow discharge zone in double
glow plasma surface alloying process. CCD technique was employed to get the temperature
distribution profile. The results show that CCD method is a simple and effective non-contact
temperature measuring technique, applicable in fields of low temperature and high temperature
plasma processes.
Numerical Simulation for Low Pressure Die Casting of Al-Alloy Motor Enclosure and Technology Improvement
Authors: Mi Guo Fa , Liu Xiang Yu , Wang Kuang Fei , Niu Ji Tai
Published: March 2009

The FDM numerical simulation software, View-Cast system, was employed to simulate
the mould-filling and solidification process in low pressure die casting (LPDC) of Al-alloy motor
enclosure. The distribution of liquid fraction, temperature field and the solidification pattern of
casting were revealed and the formation mechanism as well as distribution rule of the potential
defects, namely gas pores and shrinkage pores, were predicted. Furthermore the solutions to
eliminate them were presented. By reducing the pouring rate, the turbulent flow at the corner of
casting had eased, so the gas pores could be eliminated. Then the force-cooling system was installed
on the top of mould, which could reduce the volume of liquid islands efficiently so that the
shrinkage defects can be decreased to its limit.
Hot Stamping Processing Experiments of Quenchable Boron Steel
Authors: Bao Jun , Xing Zhong Wen , Yang Yu Ying
Published: March 2009

The quenchable boron steel is a novel type of ultra high strength steel used for
automotive parts so as to reduce the weight of the whole automobile. The hot stamping processing
experiments for bending parts were studied. The influence of the hot stamping processing
parameters, such as the heating temperature, the heat holding time and the cooling water flow
velocity, on the mechanics properties and microstructure of the hot stamping parts is obtained. And
then the optimal ranges of these parameters are determined, which provides a basis for the control
of the hot stamping process applied in complicated shape parts’ production.