Started in 1985 Semimonthly
ISSN 1005-0302
CN 21-1315/TG
Impact factor:6.155

The journal has been awarded the excellent periodical in China, and its articles are covered by SCI, EI, CA, SA, JST, RJ, CSA, MA, EMA, AIA etc., PASCAL web. ISI web of Science,SCOPUS.

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      28 May 2004, Volume 20 Issue 03 Previous Issue    Next Issue
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    Research Articles
    Microstructure and Toughness of Seeded Hot-Pressed Si3N4 Ceramics
    D.Bucevac, S.Boskovic, M.Vlajic, V.Krstic
    J. Mater. Sci. Technol., 2004, 20 (03): 241-244. 
    Abstract   HTML   PDF (252KB)
    Densification, phase transformation and fracture toughness were studied in hot-pressed Si3N4 seeded by in-house produced large, elongated β- Si3N4 seeds. A mixture of Y2O3-Al2O3 was used as the sintering aid. Concentration of seeds were varied from 0 to 6 wt pct and the sintering time at 1700℃ was varied from 1 to 4 h. Maximum fracture toughness of 9.0 MPam1/2 was measured in samples containing 5 wt pct seeds, hot pressed at 1700℃ for 4h.
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    Applied Strain Field on Microstructure Optimization of Ti-Al-Nb Alloy Computer Simulated by Phase Field Approach
    Wei GUO, Yaping ZONG, Gang WANG, Liang ZUO
    J. Mater. Sci. Technol., 2004, 20 (03): 245-248. 
    Abstract   HTML   PDF (1105KB)
    The effects of applied tensile strain on the coherent α2 →O-phase transformation in Ti-Al-Nb alloys are explored by computer simulation using a phase-field method. The focus is on the influence of the applied strain direction on the microstructure and volume fraction of the O-phase precipitates. It is found that altering applied strain direction can modify microstructure of Ti-25Al-10~12Nb (at.~pct) alloy duringα2 →O-phase transformation effectively and full laminate microstructure in the Ti-25Al-10Nb (at. pct) alloy can be realized by an applied strain only along the direction 30° away from theα2 phase <10 0> in magnitude equivalent to the stress-free transformation strain. The simulation also shows that not only the magnitude of applied strain but also the applied strain direction influences the O-phase volume fraction and the effect of strain direction on the volume fraction is up to 25%.
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    In Vitro Characterizations of PLLA/β-TCP Porous Matrix Materials and RMSC-PLLA-β-TCP Composite Scaffolds
    Dali ZHOU, Weizhong YANG, Guangfu YIN, Changqiong ZHENG, Yun ZHANG, Huaiqing CHEN, Rui CHEN
    J. Mater. Sci. Technol., 2004, 20 (03): 248-252. 
    Abstract   HTML   PDF (685KB)
    To develop a novel degradable poly (L-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) bioactive materials for bone tissue engineering, β-TCP powder was produced by a new wet process. Porous scaffolds were prepared by three steps, i.e. solvent casting, compression molding and leaching stage. Factors influencing the compressive strength and the degradation behavior of the porous scaffold, e.g. weight fraction of pore forming agent-sodium chloride (NaCl), weight ratio of PLLA: β-TCP, the particle size of β-TCP and the porosity, were discussed in details. Rat marrow stromal cells (RMSC) were incorporated into the composite by tissue engineering approach. Biological and osteogenesis potential of the composite scaffold were determined with MTT assay, alkaline phosphatase (ALP) activity and bone osteocalcin (OCN) content evaluation. Results show that PLLA/β-TCP bioactive porous scaffold has good mechanical and pore structure with adjustable compressive strength needed for surgery. RMSCs seeding on porous PLLA/β-TCP composite behaves good seeding efficacy, biocompatibility and osteoinductive potential. Osteoprogenitor cells could well penetrate into the material matrix and begin cell proliferation and osteogenic differentiation. Osseous matrix could be formed on the surface of the composite after culturing in vitro. It is expected that the PLLA/β-TCP porous composites are promising scaffolds for bone tissue engineering in prosthesis surgery.
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    Effects of Primary Annealing Condition on Recrystallization Texture in a Grain Oriented Silicon Steel
    Yuhui SHA, Fang ZHANG, Song LI, Xiaoyu GAO, Jiazhen XU, Liang ZUO
    J. Mater. Sci. Technol., 2004, 20 (03): 253-256. 
    Abstract   HTML   PDF (1226KB)
    The recrystallization texture in grain oriented silicon steel sheets, which were annealed at different primary annealing temperatures with and without an electric field, was investigated. An automated electron backscattered diffraction (EBSD) technique was used to analyze the recrystallization texture. It was found that recovery and application of electric field in primary annealing lead to an increase of {001} component and a decrease of {111} component after annealing at 900℃. The development of recrystallization texture can be explained in terms of the effects of electric field and primary annealing temperature on recovery.
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    FEM Simulation of Effect of Process Parameters on Static Recrystallization in 60SiMnA Spring Steel
    Jiahe AI, Tongchun ZHAO, Huiju GAO, Xishan XIE
    J. Mater. Sci. Technol., 2004, 20 (03): 257-260. 
    Abstract   HTML   PDF (517KB)
    Two-dimensional rigid-plastic finite element method (FEM) was used for simulation of the effect of process parameters on the static recrystallization of 60SiMnA spring steel using MARC/AutoForge 3.1 software. A thermo-mechanical coupled analysis was conducted considering the heat transfer between the workpiece, the roll and the environment, and the heat generation due to plastic work. The static recrystallization laws under different processing conditions and the predicted distribution of the static recrystallization volume fraction on the deformation cross section are presented.
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    Numerical Simulation of Brazing TiC Cermet to Iron with TiZrNiCu Filler Metal
    Lixia ZHANG, Jicai FENG
    J. Mater. Sci. Technol., 2004, 20 (03): 261-264. 
    Abstract   HTML   PDF (1044KB)
    The maximum thermal stress and stress concentration zones of iron/TiC cermet joint during cooling were studied in this paper. The results showed that the shear stress on iron/TiC cermet joint concentrates on the interface tip and the maximum shear stress appears on the left tip of iron/TiZrNiCu interface. Positive tensile stress on TiC cermet undersurface concentrates on both sides of TiC cermet and its value decreases during cooling. Negative tensile stress on TiC cermet undersurface concentrates on the center of TiC cermet and its value increases during cooling. Brazing temperature has little effect on the development and maximum thermal stress.
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    Investigation on the Tribology of Co Implanted Stainless Steel Using Metal Vapor Vacuum Arc Ion Source
    Junxia GUO, Xun CAI, Qiulong CHEN
    J. Mater. Sci. Technol., 2004, 20 (03): 265-268. 
    Abstract   HTML   PDF (1318KB)
    AISI 304 stainless steel was ion implanted with Co, and the tribological property on the surface of the stainless steel was investigated. The Co ion implantation was carried out using a metal vapor vacuum arc (Mevva) broad-beam ion source with an extraction voltage of 40 kV, implantation doses of 3×1017/cm2 and 5×1017/cm2, and ion current densities of 13, 22 and 32μA/cm2. The results showed that the near-surface hardness of Co-implanted stainless steel sample was increased by 50% or more, and it increased with increasing ion current density at first and then declined. The friction coefficient decreased from 0.74 to 0.20 after Co implantation. The wear rate after Co implantation reduced by 25% or more as compared to the unimplanted sample. The wear rate initially decreased with increasing ion current density and then an increase was observed. Within the range of experimental parameters, there exists a critical ion current density for the Co-implanted stainless steel, at which the wear rate decreased with increasing retained dose, going through a minimum and then increased. The critical ion current density in this paper is about 22μA/cm2.
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    Thermal Fatigue Behaviour of a Chromium Electroplated 32NiCrMo145 Steel
    A.Abdollah-zadeh, M.S.Jamshidi, S.M.M.Hadavi
    J. Mater. Sci. Technol., 2004, 20 (03): 269-273. 
    Abstract   HTML   PDF (1819KB)
    Thermal fatigue behavior of hard chromium electroplated steel in three different crack intensities of high contraction (HC), medium contraction (MC) and low contraction (LC) was studied. Maximum and minimum temperatures during thermal cycle were 800 and 100℃, respectively. The topography and cross sections of the samples exposed to 50, 100 and 200 thermal cycles were studied. The thermal fatigue behavior was analyzed using the data obtained from surface roughness, crack networks and stress induced during cycles. Although the as-coated sample with LC chromium contained no crack, it appeared to have a high crack density after only 50 cycles. The crack depth and width in cyclically oxidized LC coating were much less than those in MC and HC coatings. It was concluded that the LC coating protected the substrate from having cracks or subsurface oxidation during thermal fatigue. The cracks in the HC and MC coatings increased in density as well as in depth by thermal cycles. Moreover, the opening of the cracks to the substrate resulted in sub-surface oxidation.
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    A Discussion on Evolution of Microstructures and Influence Factors during Continuous Rolling of Compact Strip Production
    Hongbo DONG, Yonglin KANG, Hao YU
    J. Mater. Sci. Technol., 2004, 20 (03): 274-278. 
    Abstract   HTML   PDF (1670KB)
    The evolution of microstructures and influence factors of ultrathin hot strips of low carbon steel produced by compact strip production (CSP) techniques were investigated. The steel blocking samples of CSP six-passes were obtained, and microstructures at the different positions of workpiece for each pass were studied. At the same time, an explicit finite element technique was used to reveal the continuous rolling process. By combining experiment results with simulation analysis, the effects of plastic strain, temperature, precipitation and interval time on evolution and refinement of crystal grains have been investigated. The results are useful for the development of high strength hot strips.
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    Comparison of the Molecular Interaction Volume Model with the Wagner Formulae in the Zn-Pb-In and Zn-Sn-Cd-Pb Dilute Solutions
    Dongping TAO, Zhuo CHEN, Dunfang LI, Yifeng GAO, Qianghua SHEN
    J. Mater. Sci. Technol., 2004, 20 (03): 279-284. 
    Abstract   HTML   PDF (214KB)
    The coordination numbers in the molecular interaction volume model (MIVM) can be calculated from the common physical quantities of pure liquid metals. A notable feature of the model lie in its capability to predict the thermodynamic properties of solutes in the Zn-Pb-In and Zn-Sn-Cd-Pb dilute solutions using only the binary infinite dilute activity coefficients, and the predicted values are in good agreement with the experimental data of the dilute solutions.
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    Influence of Phase Constitution on Mechanical Performance of 12Ce-3Y-ZrO2/2.5 wt pct Al2O3 Composites
    Shuigen HUANG, Lin LI, J.Vleugels, O.V.D.Biest
    J. Mater. Sci. Technol., 2004, 20 (03): 284-286. 
    Abstract   HTML   PDF (863KB)
    The phase constitution of a composite consisting of 12 at. pct CeO2-3 at. Pct Y2O3-ZrO2/2.5 wt pct Al2O3 (3Y12Ce2.5Al) was determined by thermodynamic calculation. It is a combination of 36.9 at. pct cubic phase and 63.1 at. pct tetragonal phase at 1450℃. Green compacts were fabricated by cold isostatic pressing with powder synthesized by coating technique, and pressureless sintered at 1450℃. The fracture toughness and Vickers hardness, evaluated by the micro-indentation method, are 2.02 MPa·m1/2 and 11.395 GPa, respectively. The addition of 3 at. pct Y2O3 to 12 at. Pct CeO2-ZrO2 ceramic leads to drastically decrease in toughness compared to composites without yttria stabilizer. No monoclinic phase is detected on the surface of all the ground samples. The high content of cubic phase and lack of phase transformation can be attributed to the low toughness based on the thermodynamic prediction.
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    Density of Liquid Ni-Mo Alloys Measured by a Modified Sessile Drop Method
    Liang FANG, Zushu LI, ZaiNan TAO, Feng XIAO
    J. Mater. Sci. Technol., 2004, 20 (03): 287-292. 
    Abstract   HTML   PDF (764KB)
    The density of liquid binary Ni-Mo alloys with molybdenum concentration from 0 to 20% (mass fraction) was measured by a modified sessile drop method. It has been found that the density of the liquid Ni-Mo alloys decreases with increasing temperature, but increases with the increase of molybdenum concentration in the alloys. The molar volume of liquid Ni-Mo binary alloys increases with the increase of temperature and molybdenum concentration. The partial molar volume of molybdenum in Ni-Mo binary alloy has been approximately calculated as [13.18-2.65×10-3T+(-47.94+3.10×10-2T)×10-2XMo]×10-6m3·mol-1. The molar volume of Ni-Mo alloy determined in the present work shows a negative deviation from the ideal linear mixing molar volume.
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    Effect of Triple Annealing Treatment on Stress Relaxation of Ti-6Al-4V Alloy
    Yong LIU, Jingchuan ZHU, Zhongda YIN, Mingwei LI
    J. Mater. Sci. Technol., 2004, 20 (03): 292-294. 
    Abstract   HTML   PDF (1271KB)
    The effect of triple annealing on stress relaxation of Ti-6Al-4V alloy as well as the microstructure after stress relaxation were studied. The results showed that triple annealing treatment enhanced the resistance of stress relaxation performance, and when the temperature was rising, this effect became notable. The stress relaxation deformation mechanism is of dislocation creep at 400℃ and recovery creep at 600℃.
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    Thermomechanical Processing and Superplasticity of AZ91 Magnesium Alloy
    Rongshi CHEN, J.J.Bl, in, M.Sue'ry, Qudong WANG, Enhou HAN
    J. Mater. Sci. Technol., 2004, 20 (03): 295-297. 
    Abstract   HTML   PDF (1416KB)
    The effect of extrusion on grain refinement has been studied in the AZ91 cast ingots. It is found that grain size smaller than 10μm can be obtained by the extrusion processing. Vickers hardness measurements were also carried out to evaluate the effect of these processes on the room temperature mechanical properties. ...
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    Gibbs Free Energy and Activation Energy of ZrTiAlNiCuSn Bulk Glass Forming Alloys
    Jianfei SUN, Jun SHEN, Zhenye ZHU, Gang WANG, Dawei XING, Yulai GAO, Bide ZHOU
    J. Mater. Sci. Technol., 2004, 20 (03): 298-300. 
    Abstract   HTML   PDF (441KB)
    The Gibbs free energy differences between the supercooled liquid and the crystalline mixture for the (Zr52.5Ti5Al10-Ni14.6Cu17.9) (100-x)/100Snx (x=0, 1, 2, 3, 4 and 5) glass forming alloys are estimated by introducing the equation proposed by Thompson, Spaepen and Turnbull. It can be seen that the Gibbs free energy differences decrease first as the increases of Sn addition smaller than 3, then followed by a decrease due to the successive addition of Sn larger than 3, indicating that the thermal stabilities of these glass forming alloys increase first and then followed by a decrease owing to the excessive addition of Sn. Furthermore, the activation energy of Zr52.5Ti5Al10-Ni14.6Cu17.9 and (Zr52.5Ti5Al10-Ni14.6Cu17.9)0.97Sn3 was evaluated by Kissinger equation. It is noted that the Sn addition increases the activation energies for glass transition and crystallization, implying that the higher thermal stability can be obtained by appropriate addition of Sn.
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    Effect of Nb on Structure and Mechanical Properties of Chilled Cast Iron at Room and Elevated Temperatures
    Qijie ZHAI, Li FU, Huaying ZHAI
    J. Mater. Sci. Technol., 2004, 20 (03): 301-303. 
    Abstract   HTML   PDF (1261KB)
    Effect of Nb on microstructure and mechanical properties of chilled cast iron at room and elevated temperatures is studied in this research. The results demonstrate that the cast structure and mechanical properties of chilled cast iron at room and elevated temperatures are improved with the addition of trace amount of Nb. However, if Nb was added too much, the cast structure and mechanical properties of chilled cast iron would deteriorate. The suitable content of Nb in chilled cast iron is about 0.05% (mass fraction). Except the dissolution in the matrix of cast iron the excessive Nb will form Nb-rich phases in three morphologies. Those are lumpy NbC, complicated strip-like phase and compound with pearlite structure.
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    Cavitation Erosion Behavior of as-Welded Cu12Mn8Al3Fe2Ni Alloy
    Xiaoya, Yonggui YAN, Zhenming XU, Jianguo LI
    J. Mater. Sci. Technol., 2004, 20 (03): 304-306. 
    Abstract   HTML   PDF (1475KB)
    Cavitation erosion behavior of as-welded Cu12Mn8Al3Fe2Ni alloy in 3.5% NaCl aqueous solution was studied by magnetostrictive vibratory device for cavitation erosion. The results show that the cavitation erosion resistance of the as-welded Cu12Mn8Al3Fe2Ni alloy is much more superior to that of the as-cast one. The cumulative mass loss and the mass loss rate of the as-welded Cu12Mn8Al3Fe2Ni alloy are almost 1/4 that of the as-cast one. SEM analysis of eroded specimens reveals that the as-cast Cu12Mn8Al3Fe2Ni alloy is attacked more severely than the as-welded one. Microcracks causing cavitation damage initiate at the phase boundaries.
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    Changing Rule of Carbon-Enriched Zone and Diffusion Behavior of Carbon in Aging 0Cr6Mn13Ni10MoTi/1Cr5Mo Dissimilar Welded Joints
    Zheng LIU, Ligang WANG, Lai WANG
    J. Mater. Sci. Technol., 2004, 20 (03): 307-310. 
    Abstract   HTML   PDF (1625KB)
    The microstructures, the changing rule of carbon-enriched zone, the diffusion behaviors of elements C and Cr, and the carbide type of 0Cr6Mn13Ni10MoTi/1Cr5Mo dissimilar welded joints after aging at 500℃ for various times and after long-term service in technical practice were investigated by using the optical microscopy, electron probe microanalysis, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that in aging 0Cr6Mn13Ni10MoTi/1Cr5Mo dissimilar welded joints, the main carbides are M3C and a few carbides are M7C3 and M23C6. The M3C carbide decomposition and dissolution with increasing aging time or aging temperature and the anti-diffusion of C and Cr cause the decrease and disappearance of the carbon-enriched zone. The results are different from those of the A302/1Cr5Mo dissimilar welded joints in previous studies.
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    Aligned Solidification Structure of the MnBi Phase in Semisolidified Bi-Mn Alloy with a Static Magnetic Field
    Zhongming REN, Hui WANG, Kang DENG, Kuangdi XU
    J. Mater. Sci. Technol., 2004, 20 (03): 311-314. 
    Abstract   HTML   PDF (726KB)
    The solidification structure of Bi-3 wt pct Mn alloy grown up in the semisolid zone under the influence of a static magnetic field (up to 1.0 T) and the relation of the magnetic property with the solidification structure have been investigated experimentally. It was shown that the primary phase MnBi crystals in the alloy aligned and oriented along the direction of the applied magnetic field. The orientating tendency and the average length of the elongated MnBi crystals increased with the increase of the applied field and the solidification time. Moreover, the remanence of the alloy along the aligned direction of the MnBi phase in the case of solidification with a magnetic field was apparently anisotropic and nearly double of that without the magnetic field. This indicated that the MnBi crystals oriented and aligned along their easy magnetization axis. A model was proposed to explain the alignment and orientation growth of the MnBi crystals in a magnetic field in terms of the magnetic anisotropy of the crystals and the magnetic interaction between them.
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    Microstructural Evolution and Thermal Stability of Ultra-fine Grained Al-4Mg Alloy by Equal Channel Angular Pressing
    Hongbin GENG, Subbong KANG, Shiyu HE
    J. Mater. Sci. Technol., 2004, 20 (03): 315-318. 
    Abstract   HTML   PDF (919KB)
    Experiments were conducted to evaluate the grain refinement and thermal stability of ultra-fine grained Al-4Mg alloy introduced by equal-channel angular pressing (ECAP) at 473 K. The results show that the intensities of X-ray (111/222) and (200/400) peaks for the alloy processed by ECAP decrease significantly and the peak widths of half height become broadening compared with the corresponding value in the annealed alloy. The microstructure of 2 passes ECAPed alloy consists of both elongated and equiaxed subgrains. The residual strain in the alloy increases with increasing passes numbers, that appears as increasing dislocation density and lattice constant of matrix. An equiaxed ultra-fine grained structure of ~0.2μm is obtained in the present alloy after 8 passes. The ultra-fine grains are stable below 523 K, because the alloy retains extremely fine grain size of ~1μm after static annealing at 523 K for 1 h.
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    Microstructural Evolution in Cold-Rolled Squeeze-Cast SiCw/Al Composites during Annealing
    Wenlong ZHANG, Dezun WANG, Zhongkai YAO, Mingyuan GU
    J. Mater. Sci. Technol., 2004, 20 (03): 318-322. 
    Abstract   HTML   PDF (887KB)
    A 15 vol. pct SiCCw/Al composite was fabricated by a squeeze cast route followed by hot extrusion in the extrusion ratio of 18:1 and cold rolling to 50%. Microstructural evolution in the cold rolled composite during annealing was studied using macrohardness measurement and transmission electron microscopy (TEM). It was found that, during cold rolling the plastic flow of the matrix was restricted by the whiskers around them along the rolling direction, which resulted in different microstructure from near whiskers to far away. The cold rolled composite exhibited different microstructural development on 1 h annealing at different temperatures. Under annealing at about 100℃, recovery reaction occurred obviously and the introduction of SiC whiskers resulted in enhanced recovery reaction. Under annealing above about 200℃, recrystallization (growth of nuclei by high-angle grain boundary migration) and extended recovery took place simultaneously. When annealing temperature was increased up to 500℃, recrystallization fully took place in the cold rolled microstructure. The starting temperature of recrystallization was about 200℃. Whiskers played a role in stimulating the nucleation of recrystallization.
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    A Coprecipitation Coating Synthesis of SiC/YAG Composites
    Ning ZHANG, Hongqiang RU, Xudong SUN, Qingkui CAI
    J. Mater. Sci. Technol., 2004, 20 (03): 323-326. 
    Abstract   HTML   PDF (1011KB)
    The α-SiC in 0.5μm size powders were coated with Al2O3 and Y2O3 by a coprecipitation coating (CPC) method for fabrication of SiC/YAG composites. The same powder preparation was carried out by conventional mechanical mixing (MM) method for comparison. Two kinds of SiC/YAG composites were manufactured by pressureless sintering using the different powders, named CPC composite and MM composite thereafter respectively. It is shown that the CPC composite has the advantages of homogeneous distribution of YAG phase and of being sintered to high density at a low temperature, 100℃ lower than that of MM composite. The strength (573 MPa) and hardness (23.3 GPa) of the CPC composite are significantly higher than those (323 MPa and 13.5 GPa) of the MM composite, respectively.
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    Effect of Vibrational Modes on Sand Pressure and Pattern Deformation in the EPC Process
    A.Ikenaga, G.S.Cho, K.H.Choe, K.W.Lee
    J. Mater. Sci. Technol., 2004, 20 (03): 326-329. 
    Abstract   HTML   PDF (647KB)
    During the EPC (expendable pattern casting) process, one of the essential requirements is to prevent pattern distortion during sand filling and compaction. A new method which vibrates the system in a two-dimensional circular mode has been applied to the EPC process. The molding properties of unbonded sand obtained by this new vibration mode are investigated and compared with those in the one-dimensional vertical mode. For adequate compaction of sand, the circular vibration mode is more effective than the vertical mode. Sand became more fluidized by the circular vibration and the particle pressure coefficient was close to unity. The particle pressure coefficient, which is defined as the ratio of horizontal to vertical sand pressure, is responsible for the effectiveness of sand filling.
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    Effect of Load Distribution on Strip Crown in Hot Strip Rolling
    Hongshuang DI, Jianzhong XU, Dianyao GONG, Xianghua LIU, Guodong WANG, Xiaoming HE, Liying BA
    J. Mater. Sci. Technol., 2004, 20 (03): 330-334. 
    Abstract   HTML   PDF (629KB)
    In order to establish precision model, a software to calculate the strip crown of four-high hot rolling mill was developed by using affecting function method according to the strip crown calculation theory. The effect of work roll diameter, unit width rolling load, roll bending force, work roll crown, initial strip crown and reduction, $etc$, on load distribution effect rate was simulated by using the software. The results show that the load distribution effect rate increases with the increase of strip width, work roll diameter, unit width rolling load, roll bending force, work roll crown, initial strip crown and reduction. Based on the simulation results, base value of load distribution effect rate and fitting coefficients of six power polynomial of load distribution effect rate modification coefficient were determined considering all of the above parameters. A simplified mathematical model for calculating load distribution effect rate was established.
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    A New Method to Track Resin Flow Fronts in Mold Filling Simulation of RTM Process
    Fuhong DAI, Shanyi DU, Boming ZHANG, Dianfu WAN
    J. Mater. Sci. Technol., 2004, 20 (03): 335-340. 
    Abstract   HTML   PDF (1767KB)
    A new method to track resin flow fronts, referred to as the topological interpolated method (TIM), which is based on filling states and topological relations of adjacent nodes was proposed. An experiment on the mould filling process was conducted. It was compared with exact solutions and the experimental results, and good agreements were observed. Numerical and experimental comparisons with the conventional contour method were also carried out, and it showed that TIM could enhance the local accuracy of flow front solutions with respect to the contour method when merging flow fronts and resin approaching the mold wall were involved.
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    A Study on the Wear Resistance of Nano-Material/E51
    Yan GAO, Zhenjia WANG, Quanyou MA, Ge TANG, Ji LIANG
    J. Mater. Sci. Technol., 2004, 20 (03): 340-343. 
    Abstract   HTML   PDF (1443KB)
    Epoxy resin modified by nanometric γ-alumina or multi-walled carbon nanotubes (MCNTs) was prepared with solution mixing method, and the wear resistance of the composite was studied. The results show that when an optimum amount of nanometric alumina or MCNTs is filled in epikote51 (E51), the wear resistance of the composite will increase. When 8 wt pct nanometric γ-alumina is filled in E51, the wear resistance of the composite increases to 230%. When 10% MCNTs is filled in E51, the wear resistance of the composite increases to 226%. When nanometric alumina is filled in, the wear resistance of modified epikote51 will increase as the cure temperature is heightened.
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    Transition Metal on the Electrochemical Performances of Some Intermetallic Anodes for Lithium Ion Batteries
    Jian XIE, Xinbing ZHAO, Gaoshao CAO, Mingjian ZHAO, Yaodong ZHONG
    J. Mater. Sci. Technol., 2004, 20 (03): 344-346. 
    Abstract   HTML   PDF (423KB)
    Some transition metal antimonides were prepared by levitation melting and subsequent ball-milling. The electrochemical behaviors of these materials as new candidate negative electrode materials in lithium ion secondary batteries were investigated. It was found that they exhibited significantly larger volumetric capacity than carbon-based materials. The formation and composition of solid electrolyte interface (SEI) film were characterized by electrochemical impedance spectroscopy (EIS) and Fourier transform infra-red (FTIR) spectroscopy.
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    A Study on Alnico Permanent Magnet Powders Prepared by Atomization
    Changbin SONG, Bocksoo HAN, Ying LI
    J. Mater. Sci. Technol., 2004, 20 (03): 347-349. 
    Abstract   HTML   PDF (1462KB)
    Alnico powders were prepared by gas atomization process. Composition of the Alnico powders was Fe37.1 Al8.2 Ni17.6-Co26.6 Cu3.3 Ti7.2 (wt pct) which was the same as that of commercially available Alnico magnets. Average particle size of the powders was 119μm. Effects of heat treatment in magnetic field on magnetic properties of the powders were investigated. The optimum process of heat treatment was found as follows, heated at 870℃ for 1 min first, then cooled down to 700℃ at cooling rate 0.3℃/s in magnetic field, and finally aged isothermally for 4 h. Magnetic properties of the Alnico powders were measured and the results were that intrinsic coercivity iHc was 1.0 kOe and remanence Mr was 36.5 emu/g.
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    The Tb Doping Effect on the Room Temperature Magnetoresistance in (La1-xTbx)0.67Sr0.33MnO3 (x≤ 0.4)
    Hongwei QIN, Jifan HU, Juan CHEN, Hongdong NIU, Luming ZHU, Zhuo WANG
    J. Mater. Sci. Technol., 2004, 20 (03): 350-352. 
    Abstract   HTML   PDF (688KB)
    by Tb in (La1-xTbx)0.67Sr0.33MnO3, the room temperature magnetoresistance △R/R0 drops at first, then undergoes an increase near x≈0.1, and finally drops again. The value of room temperature magnetoresistance at a field H=12 kOe for (La1-xTbx)0.67Sr0.33MnO3 is -3.56%. The enhancement of the room temperature magnetoresistance induced by an appropriate Tb substitution in (La1-xTbx)0.67Sr0.33MnO3 is correlated with the shifts of the Curie temperature and metal-insulator temperature to near room temperature. The drop of the room temperature magnetoresistance at large Tb doping-contents may be due to its lower TC and TMI far from the room temperature.
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    Research on a New Process of Preparation for Nano-SiO2 with High Activity and Mesopores
    Ruijing ZHANG, Ke YANG, Tianying XIONG
    J. Mater. Sci. Technol., 2004, 20 (03): 353-356. 
    Abstract   HTML   PDF (1106KB)
    Nano-SiO2 with high activity and mesopores was prepared through sol-gel synthesis followed by low-temperature heat treatment and ball milling firstly in our experiments. TEM was performed to measure particle sizes. Nitrogen adsorption experiments were carried out to estimate specific surface area, porous distribution and porous ratio by BET and BJH methods. The content of Si-OH in SiO2 surface was calculated by analysis of the results of hydrogen-oxygen content mensuration (HOCM). As a result, appropriate heat treatment system and ball milling time are important to preparation for nano-SiO2 with high activity and mesopores, which are 5~50 nm particles, 5~6 nm average aperture, 85%~93% porous ratio, and 51%~55% Si-OH content in surface. Nano-SiO2 with that structure has high surface energy and activity. This process, which has simple facilities and operation rules, is a new way of preparation for nano-SiO2 with high activity and mesopores.
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    Study on the Properties of Nanometer CeO2 Doped with Zr4+, La3+, Pr3+
    Mingfen WEN, Bo YU, Qiuping WANG, Chongli SONG, Jing CHEN
    J. Mater. Sci. Technol., 2004, 20 (03): 357-360. 
    Abstract   HTML   PDF (962KB)
    Different nanometer CeO2-ZrO2 mixed oxides doped with lanthanum or ~praseodymium were prepared by coprecipi-tation. The characteristics of all mixed oxides were tested by XRD, SEM, TEM, and XPS. XRD results showed that all oxides were formed solid solution with CaF2 structure at low temperature and had good thermal stability. More Ce4+ ions were rich on the surface by XPS, which were beneficial to oxygen storage. The particle mediun sizes (d50) of all oxides powders were approximately 10~20 nm by small angle scattering goniometer. When doped Zr4+ in CeO2, the specific surface areas were improved at low or high temperature. The area of Ce0.6Zr0.3La0.04Pr0.06O2 powder had excess 110 m2/g after calcining at 923 K for 4h, even calcined at 1273 K for 4 h, the area was up to 65 m2/g.
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    Densification of Mo Alloys at 1473 K by Adding Ni-Cu Solid Solution
    Daoren GONG, Zhongmin YANG, Qiang SHEN, Lianmeng ZHANG
    J. Mater. Sci. Technol., 2004, 20 (03): 361-362. 
    Abstract   HTML   PDF (973KB)
    Mo is difficult to sinter densely at a relatively low temperature due to its high melting point. In the present paper, by adding different weight contents of Ni and Cu additives, Mo alloys have been densified at 1473 K for an hour by hot-pressing method, and the optimum contents of Cu and Ni additives have been acquired: when the contents of Ni and Cu are 3 and 2 wt pct respectively, the relative density of the sample reaches the maximum value. It was found that when the Ni-Cu solid solution was added into Mo alloys, the achieved density is higher than the case of Ni and Cu additives. The experimental results indicate that, Ni and Cu play different roles in the process of sintering, the Ni-Cu solid solution has the same function as Ni and Cu additives in the course of sintering Mo alloys, It shows more activating sintering feature for Mo than the Ni and Cu additives.
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    Study on the Forming Limit Nomogram of Tensile Stamping Operations
    Dachang KANG, Haobin TIAN, Shihong ZHANG
    J. Mater. Sci. Technol., 2004, 20 (03): 363-364. 
    Abstract   HTML   PDF (227KB)
    Based on plasticity theory and physical experiments, the quantitative relationships between elongation δ obtained by uniaxial tensile test and forming limits of tensile stamping operations are given, which mainly resolves the problem that forming limits can be derived from simple tensile test. The forming limit nomogram of tensile stamping operations is also established to apply to engineering.
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    Effect of Preparation Atmosphere on the Structure and Properties of Vanadium Pentoxide Xerogel Films
    Wen CHEN, Manzhu KE, Qing XU, Quanyao ZHU, Liqiang MAI, Li LI
    J. Mater. Sci. Technol., 2004, 20 (03): 365-367. 
    Abstract   HTML   PDF (400KB)
    In this article, the vanadium pentoxide sols are synthesized by two different routes (melted and quenched in oxygen atmosphere or in air). The structure and properties of the vanadium pentoxide xerogel films are characterized by XRD, ESR, cyclic voltammograms curves and UV-visible transmittance analysis. The results show that the sample prepared in oxygen has poorer crystallization, lower content of V4+ ions and higher Li+ insertion capacity compared with that prepared in air.
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    Preparation of Diamond-like Carbon Films on the Surface of Ti Alloy by Electro-deposition
    Fenglei SHEN, Hongwei WANG, Dijiang WEN
    J. Mater. Sci. Technol., 2004, 20 (03): 367-368. 
    Abstract   HTML   PDF (583KB)
    In this paper, diamond-like carbon (DLC) films were deposited on Ti alloy by electro-deposition. DLC films were brown and composed of the compact grains whose diameter was about 400 nm. Examined by XPS, the main composition of the films was carbon. In the Raman spectrum, there were a broad peak at 1350 cm-1 and a broad peak at 1600 cm-1, which indicated that the films were DLC films.
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CN: 21-1315/TG
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