bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and High Heat Flux Testing of Plasma Facing Materials for Future Fusion Experiments
Authors: Linke Jochen , Kapoustina A. , Pitzer D. , Rödig M. , Singheiser Lorenz
Published: March 2009

To evaluate the performance of plasma facing materials (PFM) and components for future thermonuclear fusion devices under the expected operation conditions, an in-depth material characterization and extensive high heat flux simulation tests are performed routinely in electron beam test facilities. These experiments cover both, thermal fatigue tests with power densities up to approx. 20 MWm-2 and thermal shock loads with deposited energy densities of several MJm-2. In addition, irradiation experiments have been performed in material test reactors to investigate the neutron induced material degradation.
Behavior of Thick SiC Gradient Coatings on Graphite under High Heat Flux and HT-7 Limiter Plasma Irradiation
Authors: Li H. , Li Jin Gang , Chen Jin Long
Published: March 2009

The behavior of thick SiC gradient coatings on different graphites under high power
electron beam irradiation, pulsed high energy laser impact, and HT-7 limiter plasma action was investigated. In the following tests at these facilities, the samples were examined using SIMS, EDAX, X-ray crystallography, profilometer and Auger spectroscopy. Thick SiC gradient coatings showed excellent durability under high heat flux and in real conditions of HT-7 limiter plasma irradiation. The primary results indicated that the use of multi-element doped graphite, GBST1308 (1%B4C, 2.5%Si, 7.5%Ti) with high thermal conductivity, as substrate will improve the durability
of thick SiC gradient coatings significantly.
Research on W/Cu Functionally Graded Materials as Divertor Material in China
Authors: Ge Chang Chun , Zhou Zhang Jian
Published: March 2009

Tungsten has the highest sputtering threshold of all possible candidates and the highest melting point in metal. It will be the first candidate in selecting divertor materials. Great efforts are made on research and development on W/Cu functionally Graded Materials as high performance divertor material for next generation divertor-mounted Tokamak facilities in China recently. Four different processing technologies are used and compared and some results of evaluation of
plasma-relevant characteristics of these materials are reported.
The Structure and Properties of Low Activation Ferritic / Martensitic Steels
Authors: Zhao Fei , Wan Kuibei , Wan Farong , Long Yi , Xu Yongli , Huang Qun Ying
Published: March 2009

This paper reported the low activation martensitic steels which are being studied to
develop the structural materials in fusion reactors. The steels were based on 9Cr1.5WVTa, but the effect of alloy elements was investigated by changing the amounts of alloy elements or adding other elements. The structure and properties of the steels were studied by tensile experiment, X-ray diffraction, SEM, TEM. Also the metallurgical process and heat treatment effect were discussed.
Effect of He-Injection on Irradiation Damage of High Mn-Cr Steel
Authors: Bae Dong Su , Lee Sang Ll , Nahm Seung Hoon , Choi J.W. , Takahashi H.
Published: March 2009

The high Mn-Cr austenitic steel for structure material of nuclear and/or fusion reactors from the point of view of the reduced radio-activation has been irradiated by using three irradiation modes of electron-beam irradiation, electron-beam irradiation after He-injection and electron/He+-ion dual-beam irradiation in 1250kV high voltage electron microscope (HVEM) connected with an ion accelerators to study the effect of He-injection on irradiation damage. Irradiation-induced segregation analyses were carried out by an energy dispersive X-ray analyzer (EDX) in a 200kV FE-TEM with beam diameter of about 0.5nm. Void formation was not observed in each irradiation condition. Grain boundary migration was observed in the case of electron/He+-ion dual-beam irradiation. Irradiation-induced segregations of Cr and Mn at grain boundary were observed in each irradiation
condition. The amounts of Cr and Mn segregation decreased in the cases of electron-beam irradiation after He-injection compared with other irradiation conditions.
Improvement of Thermomechanical Fatigue Life in Nitrogen Alloyed 316 Stainless Steel
Authors: Kim Dae Whan , Han Chang Hee , Ryu Woo Seog
Published: March 2009

Fatigue tests of type 316 and 316LN stainless steel were conducted at RT and 600ı,
0.8~1.5% strain range for low cycle fatigue (LCF), 300~600ı, 0% strain range for thermal fatigue (TF) and 300~600ı, 2% strain range, in-phase or out-of-phase for thermomechanical fatigue (TMF). LCF, TF, and TMF lives were increased but saturation stresses were decreased with the addition of nitrogen. The higher temperature was the lower TF life at a same temperature change. The minimum temperature change for TF failure was more than 100ı. TMF life was higher at inphase condition than at out-of-phase condition. Fracture mode was transgranular for LCF and outof- phase of TMF and almost transgranular and small intergranular for TF and in-phase TMF.
Effect of Helium and Aging Treatment on Radiation Damage Behavior in Low Activation Fe-Cr-Mn (W, V) Alloy
Authors: Kinoshita Hisao , Hu Benfu , Takahashi H.
Published: March 2009

The effects of helium and aging treatment on radiation damage behavior in low activation Fe-Cr-Mn ( W, V) alloy were investigated by electron and helium ion dual-beam irradiation in a high voltage electron microscope. Specimens were aged at 673 K, 823 K and 923 K for 1000, 3000 and 10000 hours. Electron and He ion dual-beam irradiations were performed at 627 K to 10 dpa. M23C6 type carbides were precipitated in the aged specimens, and the amount of the precipitates was increased with increasing aging temperature and aging time. He bubbles were formed during dual-beam irradiation in all of the specimens. The cavity swelling under dual-beam irradiations was increased with increasing the aging temperature and aging time. It was suggested that cavity swelling is closely related to the concentration of solutes such as Cr and C in the matrix, namely cavity growth rate becomes higher with decreasing of the solutes in solution.
Changes in the Microhardness and Young's Modulus in 2 MeV C+ Ion-Irradiated IG-110 Nuclear Graphite
Authors: Chi Se Hwan , Kim Gen-Chan , Hong Jun Hwa , Kwon Sang Chul , Chang Jong Hwa
Published: March 2009

The changes in the microhardness and Young’s modulus of the 2 MeV C+ ion–irradiated IG-110 isotropic nuclear graphite were evaluated by a dynamic ultra-microhardness test. Indentation depth and load dependency of the hardness and elastic modulus were observed possibly due to the formation of a range. Both the hardness and Young’s modulus (E) – dpa curves have shown an incubation dose for about ı 0.3 mdpa. After the incubation dose, both the hardness and E
showed a rapid increase with the dose. The doses that corresponds to these rapid increases in the hardness and E coincides with the dose that corresponds to the beginning of the irradiationinduced surface distortion, and the loss of the graphite crystallinity (amorphization).
Structure Changes in Stainless Steels Used in Nuclear Reactors and Turbo Generators after Minor Low Cycle Fatigue Deformation
Authors: Eterashvili Tamaz , Dzigrashvili T. , Vardosanidze M.
Published: March 2009

The structure of austenitic steel before and after 25% of total number of cycles of low cycle fatigue tests conducted at room temperature is studied using TEM. It is shown that the cyclic deformation of the steel proceeds heterogeneously. The microstructure of the steel is investigated in the area between the deformed and undistorted parts of the samples. The crystallography of the observed twins and the slip bands is specified. The value of local plastic deformation within a micro area of a grain is measured, and the influence of microstructure on crack initiation is discussed.
In-Situ Fabrication and Fracture Characteristics of Structural Gradient Ni/Ni-Aluminide//Ti/Ti-Aluminide Layered Materials
Authors: Chung Dong-Seok , Kim J.K. , Enoki Manabu
Published: March 2009

Ni/Ni-aluminide//Ti/Ti-aluminide laminate composite, considered as a functionally
gradient material, was manufactured by thin foil hot press technique. Thick intermetallic layers of NiAl and TiAl3 were formed by a self-propagating high-temperature synthesis (SHS) reaction, and thin continuous layers of Ni3Al and TiAl were formed by a solid-state diffusion. Fracture resistance with loading along the crack arrester direction is higher than crack divider direction due to the
interruption of crack growth in metal layers. The Ni3Al and NiAl intermetallic layer showed cleavage and intergranular fracture behavior, respectively, while the fracture mode of TiAl3 layer was found to be a intragranular cleavage. The debonding between metal and intermetallic layer and the pores were observed in the Ni/Ni-aluminide layers, resulting in the lower fracture resistance.
A New Technique for Fabrication of Flat PP/Talc Graded Material
Authors: Wen Bian-Ying , Wu Gang , Yu Jian
Published: March 2009

This work deals with a novel processing method that combined extrude with laminate
molding for preparing polymeric graded material (PGM). The variations of inhomogeneous property were generated by altering the feeding speed and/or weight ratio of the components as well as changing the order or numbers of the folded layers. Three modes of polypropylene (PP)/ talcum powder (talc) flat PGM (signed with T1, T2, T3) are fabricated successfully by using this new
technique. The preparation, structure and property of the resultant PP/talc graded composite were investigated. Results indicate that the composition, morphology and properties show a gradient variation along their thickness direction of the flat PGMs.
Study on Recrystallization Behavior of High Strength Automobile Steel Sheets Produced by CSP
Authors: Zhao Zheng Zhi , Kang Yong Lin , Mao Xin Ping , Chen Yin Li , Chen Gui Jiang , Chen Xue Wen
Published: March 2009

The recrystallization behavior of high strength automobile steel sheets (ZJ590L) developed by CSP technology is studied in this paper. The effect of the deformation temperature, reduction on the austenite grain size and the recrystallized fraction of ZJ590L steel during hot deformation has been investigated. Technique of test and analysis includes preparing stepped test piece and quantitative metallograph. The mechanism of austenite microstructure refinement has been discussed, which provides valuable references to set parameters of controlled rolling and controlled cooling process. The analysis shows that the austenite grain size fines with the increase of deformation temperature and reduction, and the recrystallized fraction increases. When the deformation temperature is above 1000°C and reduction exceeds 40%, complete recrystallization can be obtained.
Application of the Equivalent Transformation Layering Calculation Model in Heavy Cross-Section FGCs - Axis-Symmetrical Mechanics Problems
Authors: Tang Liu Ding , Zhang Xue Bin , Li Bing Zhe
Published: March 2009

Based on equivalent transformation by means of mathematically rigorous analytics, the stress analysis of heavy cross-sectional, non-homogeneous Functionally Graded Composites (FGCs) has been performed by the layering calculation model in axis-symmetrical mechanics problems. The partially calculated results of the non-homogeneous layered thick-walled metal tube are similar to the design and practice of machine forging moulds manufactured with special welding electrodes
developed by the German Capilla Company. The analysis is used complementary to the investigation of the quantitative analysis of thermo-mechanical properties, or the so-called anti-design and the optimization of the graded structure for FGCs.
Characteristic Wave Impedance of Ti-Mo System Composites and FGM
Authors: Wang Chuan Bin , Shen Qiang , Luo Guoqiang , Zhang Lian Meng
Published: March 2009

In the present paper, the relationship between characteristic wave impedance and
compositions was mainly investigated in order to find a suitable theoretical model for predicting the impedance value of Ti-Mo system composites and FGM. At first, dense Ti-Mo composites with different weight fractions of Mo were prepared. Then the transverse and longitudinal wave velocities of the samples were measured and the characteristic wave impedance values were obtained. A mixture model was adopted to estimate the characteristic wave impedance value of Ti-Mo composites. Comparisons between the estimated and experimental results demonstrated that
the suggested model was sufficiently accurate to predict the characteristic wave impedance value of Ti-Mo system composites and FGM.
Determination of the Impact Fatigue Behavior of the Mo Surface Modified Ti6Al4V Alloy
Authors: Li Xiu Yan , Li Yong Mei , Qin Yan Mei , Tang Bin , Xu Zhong
Published: March 2009

The Mo surface alloying layer was prepared on Ti6Al4V substrate using the plasma
surface alloying technique. The component, structure and hardness of the Mo surface alloying layer were investigated. The impact test was used to determine the fatigue behavior of the Mo surface modified Ti6Al4V. The results showed that the Mo surface alloying layer enhanced the surface strength of Ti6Al4V substrate. The Mo surface alloying layer has a duplex structure with diffusing and coating layers. The diffusing layer in which the component and hardness change gradually could enhance load-bearing capacity to the surface coating and ensure the durability of the coating. In the impact test, the Mo modified Ti6Al4V showed excellent fatigue behavior and the cohesive failure mode was observed.
Numerical Simulation on Thermal Shock Resistance of TiB2-Cu Interpenetrating Phase Composites
Authors: Hong Chang Qing , Zhang Xing Hong , Han Jie Cai , He Xiao Dong
Published: March 2009

TiB2-Cu Interpenetrating phase composites (IPCs) were prepared by combustion synthesis of elemental titanium, boron and copper powders. The synthesized product consisted of two spatial continuous phases: TiB2 and copper. Using the experimental data, thermo-physical and mechanical parameters of the materials established the temperature and stress fields made of FEM. Thermal
shock behavior of TiB2-Cu IPCs was also investigated using a plasma torch arc heater and the results showed no cracks were found on the thermal shock surface of the TiB2-Cu IPCs. The experimental and numerical modeling results can be used to explain the actual thermal shock resistance and reveal its complex behavior under the severe condition.
Graded Structure in SHS Ceramic-Lined Layered Pipes
Authors: Zhang Long , Zhao Zhong Min , Yang Yu Zhong , Han Bao Hong
Published: March 2009

Aiming at ceramic-lined layered pipes employed under special conditions, layered
structure of ceramic-lined pipes is redesigned by adding (TiO2+Al+C+Ni) subsystem with different contents in (CrO3+Al) main system，and the composite pipe with three-layer structure of steel substrate, the intermediate and ceramics is obtained. SEM images and EPMA analyses indicate that the intermediate is made of Cr-Ni-Fe-Al-Ti, in which Ti carbide particles or fine dendrites of Ti enrichment are embedded with graded distribution. Mechanical tests and SEM images show that as
(TiO2+Al+C) subsystem and Ni metallic additive is up to 10% and 15% of whole combustion system respectively, compressive strength and compressive shear strength of the pipe simultaneously reach the maximum values.
Porosity-Graded Piezoelectric Ceramics: Processing and Electric-Induced Displacement
Authors: Li Jing Feng , Zhang Hai Long , Takagi Kenta , Watanabe Ryuzo
Published: March 2009

Uniformly porous and porosity-graded piezoelectric ceramics were prepared by sintering powder compacts consisting of lead zirconate titanate (PZT) and organic material powders as pore-forming agents (PFA) in air atmosphere. The dielectric, elastic and piezoelectric properties of uniformly porous PZT ceramics were investigated as a function of the porosity volume fraction. The electric-field-induced deflection characteristics of the beam-shaped actuator samples were measured with electric strain gages, and compared with the values calculated from the modified classical laminate theory using the elastic and piezoelectric constants of the non-FGM porous PZT ceramics.
Gradient Microstructure Analysis of PI-SiO2 Hybrid Tubular Films
Authors: Xu Yi Kun , Zhan Mao-Sheng
Published: March 2009

PI-SiO2 hybrid seamless tubular films with gradient microstructure were prepared by
sol-gel insitu polymerization and rotational moulding process. Energy Dispersive X-Ray Spectrometry (EDS) and Field Emitter Scanning Electron Microscope (FE-SEM) were used to evaluate the spatial gradient distribution of SiO2 in the PI-SiO2 hybrid tubular films. The experimental results showed that the SiO2 particles were dispersed at nanoscale in the PI matrix, and that the size and the dispersivity of the SiO2 particles changed gradiently along the tubular film cross-section. The lower the SiO2 distribution density, the smaller the SiO2 particles. When the SiO2 content exceeded a certain value, some SiO2 nano-particles aggregated into nano-clusters with thyrsiform structure, and the nano-clusters aggregated more into limbate globoids.
Synthesis of Porous TiAl-Mn Intermetallic Compounds by Reactive Sintering Process
Authors: Yang Yoon Seok , Kim Mok Soon , Kim Won Yong
Published: March 2009

The porous Ti-45at.%Al-1.6at.%Mn intermetallic alloys were fabricated by reactive
sintering process using warm extruded mixtures consisting of elemental titanium and aluminum alloy powders and subsequent heat treatment. At the extrusion stage, three different extrusion ratios were tried in order to provide the various types of porous structure in the microstructure. It was clearly found that the shape of pore and porosity are largely dependent on extrusion ratio. With increasing extrusion ratio the porosity decreased, on the other hand, aspect ratio of porous structure
increased. The porosity measured was in the range from 35% to 45%. The maximum porosity of 45% can be obtained when the specimen was reactively sintered with the extrusion ratio of 1. A directionality of pores oriented parallel to the extrusion direction was found when the extrusion ratio of powder mixtures is 6 and above.
The Effects of Nitrogen Purity and Pressure on Combustion Synthesis of α-Si3N4 Powders
Authors: Shen Wei Ping , Wang Fei , Ge Chang Chun
Published: March 2009

α-Si3N4 powders were fabricated through combustion synthesis (CS) process, and the effects of nitrogen purity and pressure on the combustion synthesis of α-Si3N4 specimen with large dimensions were investigated. It is shown that there exists respective nitrogen pressure limits for the initiation and the propagation of the self-sustained combustion. Moreover, it is found that there is an optimum nitrogen pressure for synthesizing tailored α-Si3N4 powders while other parameters were
kept constant.
Combustion Synthesis of Al2O3-30vol%ZrO2 Nano-Submicron Structured Multiphase Ceramics
Authors: Zhao Zhong Min , Zhang Long , Wang Wei Guo , Lu Haixing
Published: March 2009

Al2O3-30vol%ZrO2 nano-submicron structured ceramics has been obtained from
high-temperature melts produced by SHS metallurgical process, SEM images show that the multiphase ceramics is mainly composed of Al2O3 matrix eutecticums in which ZrO2 fibers are up to nano-submicron scale, resulting in formation of intra-granular structures. Vickers hardness test indicates that critical value of indentation load which induces median crack to extend is 30kg, and morphologies of Vickers indentation indicate that the ceramics is performed with high fracture toughness and high plasticity. Meanwhile, SEM images show that crack extension is mainly
controlled by fiber eutecticums of intra-granular structures with nano–submicron ZrO2 phases, XRD demonstrates that toughening mechanism of stress induced ZrO2 phase transformation is considered weak through comparing volume fraction of m-ZrO2 before fracture to the one after fracture, and toughening behavior of multiphase ceramics is mainly controlled by nano-submicron phase toughening mechanism.
XPS Studies on Composite TiO2-SiO2 Thin Films Deposited on Metal Substrate by Sol-Gel
Authors: Yu Xin Gang , Ma Hong Wen , Long Fei , Zhao Hui Feng , Bi Wenrue , Luo Wu Wen , Wang Li , Liu Nanyun
Published: March 2009

Through X-ray photoelectron spectroscopy, by the aid of Ar+ sputtering, chemical composition and the valence state of elements on surface and at depth of TiO2-SiO2 thin films and metal substrates have been studied. Results show that: on surface, elements of Cr, Mn, Ti, Fe exist in the form of their respective stable state, but Si is unstable and exhibits stoichiometrical disturbance when heat treated at 800°C; at depth, after sputtering for 5 minutes and 17 minutes, elements of Cr, Mn, Ti and Ni exist in the form of their respective stable state, but Si and Fe are unstable and exhibit stoichiometrical disturbances; at depth, after sputtering for 57 minutes, all of the Cr, Mn, Ti, Si, Ni and Fe exist in the form of their respective stable state. Results of chemical composition and their content by weight percent of TiO2-SiO2 thin films and metal substrates reveal that: Fe, Cr, and Mn diffuse from metal substrates to the thin films in scale; Ni diffuses few and Si collects to the metal substrate surface
Texture Developments during Ferrite Refinement through Deformation-Enhanced Ferrite Transformation and Dynamic Recrystallization in Low Carbon Steel
Authors: Yang Ping , Yang Wang Yue , Sun Zu Qing
Published: March 2009

Texture evolutions are determined by XRD and EBSD techniques during ferrite
refinement through deformation-enhanced ferrite transformation (DEFT) and dynamic recrystallization (DREX). Evidences of transformation texture, deformation texture and recrystallization texture during DEFT are provided and compared with the texture during DREX. The influence of pass-interval during DEFT on texture is illustrated. Results are discussed in terms of the influences of ferrite grain size and deforming temperature.
Low Threshold Current Density 1.5 μm Strained-MQW Laser by n-Type Modulation-Doping
Authors: Zhang Rui-ying , Wang Wei , Zhou Fan , Bian Jing , Zhao Ling-juan , Zhu Hong Liang , Jian Shui Sheng
Published: March 2009

1.5µm n-type modulation-doping InGaAsP/InGaAsP strained multiple quantum wells
grown by low pressure metalorganic chemistry vapor decomposition technology is reported for the first time in the world. N-type modulation-doped lasers exhibit much lower threshold current densities than conventional lasers with undoped barrier layers. The lowest threshold current density we obtained was 1052.5 A/cm2 for 1000 µm long lasers with seven quantum wells. The estimated threshold current density for an infinite cavity length was 94.72A/cm2/well, reduced by 23.3%
compared with undoped barrier lasers. The n-type modulation doping effects on the lasing characteristics in 1.5µm devices have been demonstrated.
Infrared Studies of GaN1-xPx Ternary Alloys
Authors: Xu F.J. , Shen B. , Chen D.J. , Tao Y.Q. , Zheng Y.D.
Published: March 2009

Infrared reflectivity measurements of GaN1-xPx alloys and quantitative fittings using Lorentz model have been carried out. In the GaN1-xPx alloys, two competitive mechanisms that determine the carrier concentration have been put forward. The one is from the effect of the isoelectronic traps which decrease the carrier concentration while the other is from the effect of defects which increase the carrier concentration. The calculated results of imaginary part of the elastivity of GaN and GaN1-xPx alloys show that the longitudinal optical phonon-plasmon (LPP) modes shift to high frequency direction and its linewidth gradually broadens with increasing carrier concentration in GaN1-xPx, indicating that the coupling of LPP modes gradually enhances and the damping of LPP modes gradually augments.
TEM Studies of Grain Boundary Structure in a Cast Polycrystalline Silicon
Authors: Kuchiwaki Isamu , Hirabayashi Takahiro , Fukushima Hiroshi
Published: March 2009

Cast polycrystalline silicon for solar cell contains mostly straight twin boundaries which are thought to have little effect on the electrical activity. There are, however, some complicated grain boundaries in it. One of these boundaries consists of slightly curved and straight parts. The structure of this boundary was analyzed to investigate the difference of these two types of boundaries. The conventional transmission electron microscopy (TEM) found that this slightly curved boundary was the zigzag shaped boundary made by (11 _ ,2) and ( _ ,211) planes. High resolution electron microscopy (HREM) confirmed that (11 _ ,2) plane was the boundary of {112} Σ3 twin boundary which formed a straight grain boundary at the other end of the analyzed grain boundary, and also confirmed that ( _ ,2 11) plane was also the boundary of {112} Σ3 twin boundary which intersected with the former twin boundary at an angle of 120 [deg].
Comparison the Gain Characteristic of AlInGaAs/AlGaAs and GaAs/AlGaAs Quantum Wells
Authors: Gai Hongxing , Deng Jun , Li Jian Jun , Shen Guang Di , Chen Jianxin
Published: March 2009

According to the Harrison’s model, the level change of conduction and valence bands caused by the strain of AlInGaAs/AlGaAs quantum well (QW) was analyzed firstly. The energy level of the electron and hole in the AlInGaAs/AlGaAs strained and GaAs/AlGaAs unstrained QW were calculated, respectively. In addition, taking the lorentzian function, the linear gain of the two QWs were calculated and discussed. Contrast the gain performance of GaAs/AlGaAs QW with that of AlyInxGa1-x-yAs/AlGaAs QW, it can be found that the strained AlyInxGa1-x-yAs/AlGaAs QW material has more promising optical gain than that of the GaAs/AlGaAs QW.
Strain Property Studies of GaN:Mg Films Grown by MOCVD
Authors: Feng Qian , Hao Yue
Published: March 2009

The influence of Mg doping on structural and strain properties in GaN layers grown on sapphire substrates by metalorganic chemical vapor deposition was studied by means of high resolution X-ray diffraction and Raman scattering. The results showed that the disorder of GaN films aggravated and the quality reduced as Mg doping rate increasing. However, according to the theoretic calculation, the compressive stress determined by the Raman shift of the E2 mode was not due to the substitution of Mg atoms for Ga. Furthermore, the SEM measurements indicated that some Mg atoms substituted Ga to become acceptors, while most of them existed as Mg interstitials(Mgi) and aggregated at defects and dislocation, hence a great deal of cracks are introduced during decreasing temperature process for inhomogeneous strain distribution.
Coprecipitation Synthesis and Photoluminescence of BaMgAl10O17:Eu2+ Phosphor for PDP Application
Authors: Zhang Zhan Hui , Wang Yu Hua
Published: March 2009

Single phase of Ba1-xEuxMgAl10O17(0.02≤x≤0.14) phosphors were first successfully prepared by coprecipitation method at 1300°C, which is 300°C lower than the temperature of solid-state method. Different precipitants were used to evaluate the changes in the morphology and luminance properties. When using (NH4)2CO3 as precipitant, the phosphor particle without agglomeration has a more regular shape and uniform distribution. Their photoluminescence was
investigated under UV and VUV region, respectively. The emission spectrum excited by 254nm or 147nm showed a characteristic wide band with the peak at about 450nm. The synthesized phosphor showed much stronger emission intensity than that prepared by solid-state method, especially using (NH4)2CO3 as precipitant, it indicated that this novel process will be great potential in practical use.
Development of Electrode Materials for Semiconductor Devices
Authors: Murakami Masanori , Koide Yasuo , Moriyama Miki , Tsukimoto Susumu
Published: March 2009

Recent strong demands for optoelectronic communication and portable telephones have encouraged engineers to develop optoelectronic devices, microwave devices, and high-speed devices using heterostructural compound semiconductors. Although the compound crystal growth techniques had reached at a level to control the compositional stoichiometry and crystal defects on a nearly atomic scale by the advanced techniques such as molecular beam epitaxy and metal organic chemical vapor deposition techniques, development of ohmic contact materials (which play a key role to inject external electric current from the metals to the semiconductors) was still on a trial-and-error basis. Our research efforts have been focused to develop, low resistance, refractory ohmic contact materials using the deposition and annealing techniques for n-GaAs, p-ZnSe, InP, p-SiC p-CdTe etc. It was found the growth of homo- or hetero–epitaxial intermediate semiconductor layers (ISL) was essential for low resistance contact formation. The importance of hetero-structural ISL was given taking an example of n-type ohmic contact for GaAs.
Theoretical Analysis of Electron Statistics for n-Type Diamond
Authors: Koide Yasuo
Published: March 2009

In order to understand carrier statistics in phosphorus-doped n-type diamond, electron statistics involving compensation and deep-dopant effect are theoretically analyzed. For n-diamond with a compensation ratio (c) larger than 1x10-4, the electron concentration (n) at room temperature (RT) is insensitive to the donor concentration (ND) and reduced with increasing the c value. On the other hand, for diamond with a c value smaller than 1x10-4, the n value at RT increases with increasing the ND value and is insensitive to the c value. Similarly, the length of Debye tailing (ln) at RT is reduced with increasing the c value for n-diamond with c>1x10-4 and is insensitive to the c value for n-diamond with c<1x10-4. However, it is found that an increase of temperature is effective to increase the n value and to reduce the ln value. The n value as large as 1015 cm-3 and the ln value as small as 100 nm are expected to be achieved at an elevated temperature of 473 K.
Growth of Hg1-x(Cd1-yZny)xTe on Si(111) by Isothermal Vapor Phase Epitaxy
Authors: Wang J.F. , Lalev G.M. , Isshiki M.
Published: March 2009

The quaternary HgCdZnTe (MCZT) epilayer was successfully grown on lattice matched Cd0.96Zn0.04Te/Si(111) substrates using isothermal vapor phase epitaxy (ISOVPE) method. It was found that Si wafer is an excellent barrier against Hg and Cd diffusion. Cross-sectional images reveal a flat and well-distinguished interface between MCZT and Si, and voids formed due to interdiffusion was not observed in MCZT layer above the Si wafer. It was demonstrated that it was possible to yield an almost homogeneous MCZT epilayer without compositional gradient by selecting suitable growth time.
Effects of Deformation on Electric Conductivity in Al-Zr Alloys
Authors: Park Su Dong , Kim Byung Geol , Lee Hee Woong
Published: March 2009

Electric conducting behavior, sectional residual stress and texture in deformed Al-Zr alloy were investigated in order to investigate effect of deformation on electric conductance. {111} textures were developed in the wire of deformed Al-Zr alloy and most strong intensity of {111} texture was observed at the core in the cross section of the wire. Residual stress was mainly measured at the surface and , especially, measured at the core in the case of 4.5Φ wire, also, electric conductance was higher at the surface than at the core. This means that electric conductance might be affected by distribution of the residual stress.
Au as an Acceptor in Thermoelectric Bismuth Antimony Telluride Alloys Prepared by Mechanical Alloying Process
Authors: Yoo Hyun Jae , Lee Chang Ho , Park Yong Ho , Park Ik Min
Published: March 2009

Effect of Au (0-0.3 wt.%) on the thermoelectric properties of Bi1Sb3Te6 alloy prepared by mechanical alloying process has been investigated. The Seebeck coefficient decreases with Au content. The Seebeck coefficient of Au-free alloy at room temperature reaches a value of 250 µV/K, which is the maximum. Because of the increased power factor, the figure of merit increases with Au content up to 0.03 wt. % and its value at room temperature is about 2.8×10-3/K, the highest value
among the prepared alloys. The Hall measurement shows that the carrier concentration increases with Au content, which explains the reason why the power factor has increased. The XRD patterns show that the intensities of (2 0 5), (0 0 18), (0 2 10), (1 0 19), (1 2 5), and (2 1 10) planes increase with Au
content. The atomic distance of these complex planes is longer than that of other main planes, and the chemical bonding strength of these complex planes between constitutional elements is weaker than that of other main planes. As a result, a portion of electrons as minor carrier is trapped into accept level of Au atoms and/or clusters. The XPS observation result, which a portion of Au atoms is chemically shifted in contrast to Bi, Sb and Te atoms are not, explains that Au behaves as an acceptor.
Synthesis and Characterization of a New Organic Photochromic Function Material
Authors: Liu Guang Fei , Liu Lang , Jia Dian Zeng , Hu Xin , Yu Kaibei
Published: March 2009

A new organic photochromic function material containing pyrazolone-ring,
1-phenyl-3-methyl-4-(4-fluobenzal)-pyrazolone-5 thiosemicarbazone (PM4FBP-TSC) was synthesized and characterized by elemental analysis, IR spectrum and 1H NMR spectrum. The photochromic properties and photocolored kinetics of PM4FBP-TSC were studied by Time-dependent UV-vis reflective spectra and fluorescent spectra under irradiation of 365nm light. The structure of PM4FBP-TSC was determined by single crystal X-ray diffraction. Space group Pbca with cell
dimensions of a = 18.445(4) Å, b = 11.987(2) Å, c = 19.249(4) Å, V = 4256.1(18) Å3, Z = 8 and R = 0.0521. The crystal structure analysis of photocolored product of PM4FBP-TSC showed that the photochromic phenomenon was due to the photoisomerization from enol form to keto formı and the mechanism of intermolecular proton transfer was applied to interpret the photochromism. The
photoisomerization belongs to the first-order reaction by computation, and kinetic reaction constant is k1 = 6.85 × 10-5 s-1.
Structural Properties of Sputter-Deposited ZnO Thin Films Depending on the Substrate Materials
Authors: Myung Ju Hyun , Kim Nam Ho , Kim Hyoun Woo
Published: March 2009

We have demonstrated the growth of ZnO thin films with c-axis orientation at room
temperature on various substrates such as Si(100), SiO2, and sapphire by the r.f. magnetron sputtering method. X-ray diffraction (XRD) and scanning electron microscopy altogether indicated that the larger grain size and the higher crystallinity were attained when the ZnO films were deposited on sapphire substrates, compared to the films on Si or SiO2 substrates. The c-axis lattice constant decreased by thermal annealing for the ZnO films deposited on Si or SiO2 substrates, while increased by the thermal annealing for the ZnO films grown on sapphire substrates.
Effect of Pattern Shape on the Crystallization in FALC Process
Authors: Kim Byung Soo , Kim Young Bae , Choi Duck Kyun
Published: March 2009

Considering practical application of field aided lateral crystallization process in channel region of thin film transistors, there might be a different crystallization behavior dependent on the shape of channel to be crystallized. In this study, channel array with various aspect ratios was prepared and the Cu field aided lateral crystallization process was carried out at 500ı for 10 hours with applying 30V/200㎛ through common electrodes for the sake of the actual channel area crystallization. Both the fraction of crystallized area and the degree of crystallization increase as the aspect ratio of channel become away from 1.
Fabrication of Glass Mixing Channels and Silicon Detection Cell with 45˚ Mirror Surfaces for the Indophenol Sensing Device
Authors: Shin Kyu Shik , Park Joon Shik , Park Kwang Bum , Park Hyo Derk , Kim Jeong Rim , Kim Min Chan
Published: March 2009

Design and fabrication of micro mixing cells and detection cells were investigated. Glass micro mixing cells with island structures among channels were fabricated using sand blaster methods. Depth and width of mixing channel were 200 ㎛ and 180 ㎛ and island size was 90 ㎛ by 90 ㎛. Two 45° mirrors surfaces faced on each other in one detection cell which were fabricated by silicon anisotropic etching using 20% TMAH (Tetramethylammonium hydroxide) solution with 20% or 30% IPA (iso propyl alcohol) at 80°C, respectively. Up side glass wafer for mixing cell and down side silicon wafer for detection cell were bonded using anodic bonding method at 350ı, -600 V and 300 N. Synthetic indophenol was injected at inlet and moved to the detection cell through the mixing channel. HeNe laser of 632.8 nm was focused on one side of a 45° mirror, and passed through indophenol solution until the other side of a 45° mirror. The light of 632.8 nm was absorbed in indophenol solution between two 45° mirrors at detection cell. By the Beer-Lambert’s law, indophenol concentration could be calculated from the measured result of the absorbance.
Fabrication of Pressure Sensors with Diaphragm by Electro-Chemical Etch-Stop
Authors: Lee J.H. , Oh D.H. , Lee G.J. , Joo S.C. , Yang B. , Kim Sung Jin , Kim Chang Joo
Published: March 2009

A diaphragm, the most important part of pressure sensor, was successfully fabricated by an electro-chemical etch-stop (ECES) technique. It was important to control the thickness of the diaphragm precisely. We compared characteristic results of diaphragms by electro-chemical etch-stop with those by time-control etch-stop (TCES). The 4 inch n-Epi/p-substrate with 16±1 ㎛ thickness was utilized because the thickness of the diaphragm fabricated by ECES is controlled by the thickness of Epi.. The etching of silicon wafer was carried out in the solution (25 wt% KOH) at 80°C, using 3 electrode system with potentiostat. Proper voltages were applied to etch p/n-type silicon wafer after determined open circuit potential (OCP) and passivation potential (PP) of n and p-type silicon, respectively. Thickness of diaphragms fabricated by ECES was controlled in the range of 16±1 ㎛
while that by TCES was in the range of 16.1±2 ㎛. The roughness of diaphragm was 52±5 Å. When the pressure of 50 kPa was applied on the pressure sensor using the diaphragm fabricated by ECES, the error rate was improved to ±10 ㎷. In the case of the error rate of pressure sensor using the diaphragm fabricated by TC was in the range of ±25 ㎷ under the same condition.
Perspective in Application of the Phase Field Theory to Smart Materials Performance
Authors: Hsu T.Y. , Meng Q.P. , Rong Yong Hua , Jin Xue Jun
Published: March 2009

Previous works on the kinetics of martensitic transformation in shape memory materials through Landau theory and the application of the phase field theory to study phase transformations in alloys are briefly reviewed. Based on field model to improper martensitic transformation proposed by Wang and Khachaturyan in 1997, a simpler model is suggested. Using this model, the motion speed and shape of parent/martensite and martensite-martensite interface are quantitatively described, which are important factors to be considered in design of smart device using shape
memory materials as a main element.
Effect of Aging Treatment on High Temperature Strength of Nb Added Ferritic Stainless Steels
Authors: Ahn Jae Cheon , Sim Gyu Man , Lee Kyung Sub
Published: March 2009

Effects of aging treatment on high temperature strength of Nb added ferritic stainless steels for automotive parts were investigated. Hot tensile tests were carried out at 700 °C after the aging at 700 °C for different aging times using Gleeble 1500. High temperature strength of all steels decreased as the aging time increased. In Nb free steels, the reduction in high temperature strength is mainly due
to grain growth. On the other hand, in Nb added steels, the reduction in high temperature strength occurred by Nb precipitation. It was observed that Fe2Nb (Laves phase), Nb(C,N) and Fe3Nb3C were precipitated out during the aging at 700 °C in Nb added steels. The coarsening rate of Fe2Nb was higher than that of Nb(C,N). Fine Fe2Nb precipitates formed during at the early stage of aging
contributed to high temperature strength in 0.01C-0.38Nb steel. However, coarse Fe2Nb particles formed during the aging were very detrimental to high temperature strength. The coarsening of Fe2Nb was relatively retarded by adding Mo.
Superelasticity in TiNi Alloys and Its Applications in Smart Systems
Authors: Cai Wei , Zheng Yu Feng , Meng Xianglong , Zhao Lian Cheng
Published: March 2009

The superelasticity is one of the most important properties of TiNi alloy, which has been widely used in the smart systems of many fields, such as aerospace, aviation, biomedicine and energy etc. The current state of superelasticity of TiNi alloy has been reviewed with emphasis on the superelasticity, phase transformations, thermo-mechanical treatment and their relationship. The mechanisms of linear superelasticity and non-linear superelasticity have been revealed. Some successful applications based on the superelasticity of TiNi alloys in smart systems have been
introduced.
Electronic Structure Analysis for the Effect of Hf, Zr Addition on the Ms of TiNi Alloys
Authors: Cui Lin , Wang Xiao Dong , Qi Min , Yang Da Zhi
Published: March 2009

By using the discrete variational method and constructing cluster model, the effect of a few Hf、Zr addition on martensite transformation temperature of TiNi alloy was investigated in electronic level. It is found that the bond order of the strongest bond in the clusters is promoted by introducing the Hf、Zr atoms and the magnitude of bond order is ascendant with increasing number of Hf、Zr atoms in the cluster. At the same time, contour plots of valence charge density on the parent (110) plane show the variety on bond. The change of martensite transformation temperature
of TiNi alloy with Hf、Zr concentrations can be reflected by the value of the density of states at the Fermi level for the (110) crystal plane.
Effect of Ni-Content on Shape Memory Behavior of Ti-Rich Ti-Ni Melt-Spun Ribbons
Authors: Xing Hongyang , Khantachawana Anak , Kim Hee Young , Miyazaki Shuichi
Published: March 2009

The microstructure and shape memory behavior of Ti-rich Ti-Ni melt-spun ribbons with various Ni-contents were investigated. Ti-xNi(x=40~48at%) ribbons were fabricated by the melt-spinning method at the rotation speed of 5000rpm. They were heat-treated at 1073K for 3.6ks. It was found that the Ti-40at%Ni as-spun ribbon exhibited almost complete amorphous structure, while the specimen with more Ni-content, such as 48at%Ni ribbon exhibited the coexistence of amorphous and crystalline structures. It was also found that the maximum shape recovery strain increased with increasing Ni-content. The Ti-40at%Ni ribbon was very brittle
because of many Ti2Ni precipitates formed.
Effects of Pre-Strain and Nb Content on Transformation Temperatures in Ti-Ni-Nb Shape Memory Alloy
Authors: Sakuma Toshio , Mihara Yuji , Ochi Yasuo , Ozawa M. , Okita K. , Okabe N.
Published: March 2009

Ti-Ni-Nb shape memory alloy has a wide transformation hysteresis, and has been used as coupling devices and so on. However systematic researches of the influence of the amount of Nb addition on transformation temperatures are few. The purpose of this work is to clarify the influences of pre-strain and Nb content on transformation temperatures in Ti-Ni-Nb shape memory alloys. The specimens were Ti-Ni-Nb alloys (Ni/Ti=1.0, Nb=0-15at%), annealed at 1223 K for 0.3 ks. The variation of transformation temperatures with pre-strain and Nb content were investigated experimentally. The variation of As, Ms and transformation temperature hysteresis with pre-strain and Nb content will be discussed in relation to the elastic strain energy and the volume fraction of slip-deformed martensite.
Shape Memory Alloy Pipe-Joint with Copper Coating
Authors: Wang Lei , Yan De Sheng , Jiang Zhi Min , Rong Li Jian
Published: March 2009

In order to improve the performance of pipe couplings, a technique has been developed to electroplate copper on the inner surface of Ni-Ti-Nb pipe-joints after pre-deformation. Gas leak tightness and tensile tests were conducted to evaluate the performance of the couplings both with and without copper coating. It was found that electroplating a thin copper layer on the inner surface of the pipe-joint effectively solved the problem of leakage and greatly enhanced the pull-out force of the couplings. Furthermore, the pipe-joints without ribs can be demounted easily after being cooled to the liquid nitrogen temperature and benefit the maintenance of the pipeline.
Effect of Ce Addition on Martensitic Transformation Behavior of TiNi Shape Memory Alloys
Authors: Liu Ailian , Meng Xianglong , Cai Wei , Zhao Lian Cheng
Published: March 2009

The effect of cerium addition on the martensitic transformation behavior and microstructure of Ti50-x/2Ni50-x/2Cex (x=0, 0.5, 2, 5 and 10at.%) alloys have been studied by differential scanning calorimetry (DSC) and energy dispersive spectroscopy (EDS). The results show that the addition of cerium affects the martensitic transformation temperature obviously. With the increase of Ce content, the phase transformation temperatures first increase rapidly and then decrease slightly, which may be attributed to the change of the Ni/Ti ratio in matrix. Moreover, the dispersed Ce-riched second particles with various morphologies are observed in TiNiCe alloys.
Mechanical Properties of (Pt, Ir)Ti
Authors: Yamabe-Mitarai Yoko , Hara Toru , Miura Seiji , Hosoda Hideki
Published: March 2009

We have suggested B2-(Pt, Ir)Ti as high temperature shape memory alloys. The phase transformation of (Pt, Ir)-50at% Ti from B2 to B19(2H) or 4H(4O) structures was investigated in our previous study. The microstructure suggested martensitic transformation. In this study, thermal expansion measurement and cyclic compression test were performed for (Pt, Ir)Ti to investigate if the shape memory effect appears. High temperature strength was also investigated because phase
transformation temperature of the (Pt, Ir)Ti is above 1273 K and high strength is necessary as high temperature shape memory alloys in order to suppress dislocation motion and stabilize martenstic transformation. The potential of (Pt, Ir)Ti as high temperature shape memory alloys will be also discussed.
Wear Behavior of an Austempered Ductile Iron Containing Mo-Ni-Cu
Authors: Yazdani Sasan , Rahimi M.A.
Published: March 2009

The aim of the this investigation is to study the influence of Ni on tribiological behavior of an austempered ductile iron (ADI) containing Mo, Ni and Cu. Ductile irons with chemical composition Fe-3.56%C– 2.67%Si –0.25%Mo–0.5%Cu and Ni contents of 0.8 and 1.5% were cast into standard Y-blocks. Wear test samples were machined off from the bottom section of blocks. Austenitizing heat treatment was carried out at 870°C temperature followed by austempering at 270, 320, and
370°C for 5-1140 minutes. The wear test was carried out by using block-on-ring test machine. Sliding dry wear behavior was studied under applied loads of 50, 100 and 150N. The results show that wear resistance is independent of austempering temperature with an applied load of 50N, but there is a strong dependence at higher austempering temperatures with applied loads of 100 and 150N. Wear mechanism is described as being due to subsurface fatigue, with cracks nucleated at plastically, deformed graphite interfaces. The wear controlling mechanism is the crack growth when wear shows a dependence on applied load and austempering temperature.