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Volume 0,Issue 12,2003 Table of Contents

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  • 1  Experimental and Finite Element Study of Influence of Heat Treatment on Creep Behavior of Short Fiber Reinforced Metal Matrix Composite
    Yue Zhufeng Hu Weibin Lu Zhenzhou
    2003(12):965-970.
    [Abstract](1142) [HTML](126) [PDF 0.00 Byte](0)
    Abstract:
    采用试验和有限元方法研究了热处理制度对金属基短纤维复合材料(MMC)蠕变性能的影响,同时考虑了2种不同热处理制度和1种铸造状态。试验结果表明,MMC的蠕变响应与热处理制度有关。在相同蠕变应力时,铸态试样有最小的最小蠕变应变率和最长的蠕变寿命,而热处理制度2(试样在550℃保温24h后随炉冷却)具有明显的最大的最小蠕变应变率和最短蠕变寿命,热处理制度1(试样在550℃保温24h后水冷)具有中等的最小蠕变应变率和中等的蠕变寿命。用单胞模型结合有限元方法模拟分析了热处理的影响,结果表明,热处理制度的影响可以归于热处理引起的残余应力和残余应变以及它们的历史,具体可以归于基体的蠕变耗散能、纤维轴向力和纤维—基体界面力。同时考虑了单胞模型的参数对上述分析结果的影响。
    2  A Model for Age Strengthening of Al Alloys with Plate/Disc-like or Rod/Needle-like Precipitate
    Liu Gang Zhang Guojun Ding Xiangdong Sun Jun Chen Kanghua
    2003(12):971-975.
    [Abstract](1535) [HTML](130) [PDF 0.00 Byte](23)
    Abstract:
    An unified model is presented to establish the quantitative relations between yield strengths of aged Al alloys containing plate/disc like or rod/needle like precipitates and the sizes, volume percentages of precipitates, The nucleation, growth and coarse of the precipitates are integrated into the age strengthening model based on some acceptable assumptions. The aging strengthening of AA6061 and an Al Zn Mg alloy has been satisfactorily simulated and predicted. Furthermore, the dependence of aspect ratio of plate/disc like or rod/needle like precipitates on aging temperature and processing condition is discussed in detail.
    3  Optimum Design of W/Cu Functionally Graded Material for Thermal Stress Mitigation
    Ling Yunhan Bai Xinde Li Jiangtao Ge Changchun
    2003(12):976-980.
    [Abstract](1345) [HTML](137) [PDF 0.00 Byte](9)
    Abstract:
    运用有限元软件对W/Cu梯度材料进行了热应力优化设计,结果表明,在30MW/m^2的表面热流负荷下,经过优化设计的W/Cu功能梯度材料有较好的热应力缓和效果,与非梯度材料相比等效热应力降低了62.3%,表面工作温度下降了50℃;与单纯金属W相比,W/Cu梯度材料的表面工作温度较之大幅度降低445℃。
    4  Bonding Ceramics with Al/Ti/Al Multilayers by in Situ Formation of Intermetallic Compound
    Zou Guisheng Wu Aiping Ren Jialie Yang Jun Liang Chenjian Li Xiaoning
    2003(12):981-985.
    [Abstract](1314) [HTML](131) [PDF 0.00 Byte](9)
    Abstract:
    用Al/Ti/Al复合层作连接材料,通过连接温度下原位生成金属间化合物真空连接Si3N4陶瓷。研究了Al与Ti的厚度匹配和工艺参数对接头显微组织及其强度的影响和接头的形成过程。结果表明:当原位生成的连接层金属组织为Al3Ti/Ti/Al3Ti时,由于纯金属间化合物Al3Ti脆性大,且其与剩余Ti片的结合强度低,陶瓷接头强度低;当连接层金属组织为大量Al3Ti颗粒加少量Al基固溶体时,连接层金属能获得良好的强化效果,与用纯Al连接的接头相比,接头室温和高温强度显著提高。Al与Ti的厚度匹配和连接参数适当时,接头室温和600℃剪切强度可分别达到89.4MPa和29.7MPa。
    5  Properties of Ni/SCO Anode Supports Prepared by Tape Casting
    Cheng Jigui Li Haibin Liu Xingqin Meng Guangyao
    2003(12):986-990.
    [Abstract](1385) [HTML](132) [PDF 0.00 Byte](9)
    Abstract:
    以有机基流延工艺制备出了不同Ni含量的NiO/Sm0.2Ce0.8O1.9(NiO/SCO)燃料电池阳极支撑体膜。研究了制备工艺条件和Ni含量等因素对阳极膜微结构和性能的影响。试验结果表明:NiO/SCO流延生坯的烧结温度对最终阳极烧结体的孔隙特性有着决定的影响;为获得具有较高孔隙率和一定孔径分布的阳极烧结体,生坯的烧结温度应不超过1350℃;此外,不同含Ni量阳极流延生坯的烧结行为及烧结体的性能也存在明显的差异,在相同的烧结温度下,高含Ni量阳极烧结体的孔隙率和孔径都明显小于低含Ni量的烧结体,其晶粒的平均尺寸则增大。对不同温度下Ni/SCO阳极电导率的测量结果则表明,Ni/SCO阳极的导电性能也与其Ni含量和制备工艺有着密切的关系。
    6  Chemical Reactions in Activated Al-Ti-C Powder Mixture under Action of Laser Beam
    Huang Yanlu Ma Naiheng Zou Dening Liang Gongying Su Junyi
    2003(12):999-1002.
    [Abstract](1165) [HTML](129) [PDF 0.00 Byte](0)
    Abstract:
    在激光扫描涂覆Al-Ti-C活化粉料层的铝合金试样过程中,突然停止激光发射,以在激光束前面形成合成反应过程中不同阶段所产生的组织,判断所发生的化学反应,即先发生3Al Ti→Al3Ti反应,形成块状Al3Ti;以后再发生Al3Ti C→TiC 3Al反应,形成大量TiC颗粒。将实验与数值模拟相结合,采用试错法求得:3Al Ti→Al3Ti的反应温度为650℃,Al3Ti C→TiC 3Al的反应温度为810℃。
    7  Influence of Ca Concentration in Electrolyte and Hydrothermal Conditions on the Morphology and Composition of the TiO2/Hydroxyapatite Composite Layer by Microarc Oxidation
    Zhang Yong Huang Ping Xu Kewei Han Yong
    2003(12):1007-1010.
    [Abstract](1580) [HTML](139) [PDF 0.00 Byte](0)
    Abstract:
    It was found that a homogeneous and porous titania layer containing Ca and P was formed and converted into a duplex oxidation layer with hydroxyapatite crystallography by the micro arc oxidation of titanium in calcium phosphate electrolyte. The layer morphology and phase composition were not significantly changed by the Ca concentration. Only the concentration of Ca2+ions in solution, the related Ca and P content and the Ca/P atom ratio in the layer increase with increase of Ca concentration in the lower concentration of Ca. It was noted that the HA crystal morphology, the phase ratio and the Ca/P ratio vary with the hydrothermal temperature and Ca concentration of the electrolyte. The HA crystals can be fined by shortening the hydrothermal time. The above results contribute to the optimization of the composition and morphology of the TiO2/hydroxyapatite composite layer on biomedical titanium.
    8  Study on Hydrogen Permeation Process in Titanium and Ti Alloys
    Cui Changjun Peng Qiao
    2003(12):1011-1015.
    [Abstract](1530) [HTML](149) [PDF 0.00 Byte](0)
    Abstract:
    The processes of permeation and diffusion of hydrogen in Ti and Ti alloys can be described into three styles: the hydrogen permeating into Ti matrix and dissolved from and titanium hydride diffuses into Ti matrix under a hydrogen pressure; the hydride diffuses with the dislocation movement; and the titanium hydride forms and moves.
    9  Effect of Grain Size on the Oxidation Behavior of Cu-20Ni-20Cr Alloy
    Cao Zhongqiu Niu Yan Wu Weitao
    2003(12):1016-1020.
    [Abstract](1429) [HTML](128) [PDF 0.00 Byte](12)
    Abstract:
    为探讨晶粒尺寸变化对三元复相合金氧化行为的影响,采用机械合金化制备了纳米晶三元Cu-20Ni-20Cr合金,并对比研究了该合金与同成分的铸态合金在700℃~800℃,0.1MPa纯氧气中的氧化行为。结果表明,铸态合金表面没有形成连续的Cr2O,保护膜,而是形成了含有所有组元氧化物及它们复合氧化物的复杂氧化膜结构。纳米晶Cu—20Ni—20Cr合金在700℃时合金表面形成了连续的Cr2O3氧化膜,而800℃时虽没有形成Cr2O3外氧化膜,但氧化膜规则平坦,外层是CuO,中间层是Cu2O,NiO和Cr2O3组成的混合氧化物区,内层则形成了一薄但不连续的Cr2O3层。晶粒细化降低了合金表面形成Cr2O3氧化膜所需活泼组元Cr的临界浓度。
    10  Effect of Be on the Recrystallization Dynamics and Aging Properties of Aluminum Alloy 7475
    Li Yao Xia Lu Yang Junjie
    2003(12):1021-1024.
    [Abstract](1242) [HTML](124) [PDF 0.00 Byte](0)
    Abstract:
    通过对工业生产的7475铝合金加入不同含量的铍,研究了铍对合金的再结晶动力学及时效行为的影响。实验结果表明:加入0.023%Be能有效地提高7475铝合金的再结晶温度,降低再结晶速度,使合金的晶粒得到细化,且硬度值仍高于不含铍的合金;铍含量为0.7%时,上述影响减弱。铍能有效地降低7475铝合金的时效硬化时所需时间,同时提高了合金的硬度值,HB最高可达1400MPa。借助电子衍射分析,观察并讨论了合金中的析出相η′相、β相与基体间的位相关系的变化和差异。
    11  Study on the Process and Properties of Nano-sized Polycrystal Zirconia Powders by Co-precipitation in Super-alkaline Medium
    Tan Qiangqiangl Tang Zilong Zhang Zhongtai Yao Weihua Fang Kemingl
    2003(12):1025-1028.
    [Abstract](1203) [HTML](130) [PDF 0.00 Byte](1)
    Abstract:
    采用引入有机添加剂的超强碱共沉淀法可制备出粉末粒子尺寸为10nm左右的高纯纳米多晶氧化锆粉末。通过控制适当的工艺条件,得到了室温稳定的纳米四方/立方多晶氧化锆粉末。用X射线荧光光谱、X射线衍射、透射电镜、粒度分析仪等手段对粉末性能进行了表征。实验结果表明:超强碱共沉淀法所制备的粉末具有纯度高、氯离子等杂质少等特点;该粉末在室温和小于873K热处理时,均以稳定的立方或四方相存在;经873K处理的粉末粒子尺寸为10nm左右;在1123K处理后,形成固溶完全的稳定纳米四方多晶氧化锆粉末,粒子尺寸小,分散性好,粒度分布窄。与其它湿化学方法相比,添加聚合物的超强碱共沉淀法具有工艺操作简单、节约资源和环境污染小的优点。
    12  Combustion Synthesis Ternary Carbide Ti2AlC1-x
    Guo Junming Chen Kexin Ge Zhenbin Zhou Heping Ning Xiaoshan
    2003(12):1029-1032.
    [Abstract](1240) [HTML](134) [PDF 0.00 Byte](9)
    Abstract:
    采用Ti,Al和C元素粉末为反应物原料,通过燃烧合成法首次成功地制备出了单相三元碳化合物Ti2AlC1-x。实验结果表明:若以“理想”晶体结构化学式Ti2AlC化学计量比为起始反应原料配比,燃烧产物主晶相为Ti2AlC2;以缺碳的非化学计量比(Ti2AlC1-x)为反应原料配比,即Ti:Al:C=3:1.5:1=2:1:0.7(摩尔比),得到单相的燃烧产物Ti2AlC1-x。从热力学原理的角度探讨了不同原料摩尔配比对燃烧产物相组成的影响机理。
    13  Synthesis of p-Hydroxybenzoate Esters with TiSiW_(12)O_(40)/TiO_2
    Yang Shuijin Liang Yongguang Sun Jutang
    2003(12):1033-1036.
    [Abstract](1379) [HTML](137) [PDF 0.00 Byte](0)
    Abstract:
    P hydroxybenzoate esters were synthesis using ethanol, propanol, butanol and p hydroxybenzoic acid as reactants, and reaction conditions. It is shown that TiSiW12O40/TiO2 is an excellent catalyst for the synthesis of p hydroxybenzoate esters, and that the optimal reaction conditions are 4:1 for the molar ratio of alcohol to acid, 2.0%of total reactant mass for the catalyst, and 2 h for the reaction time. Under these conditions, yields of 87.5%, 89.2%and 91.1%can be reached for the ethyl ester, propyl ester, and butyl ester, respectively.
    14  Preparation of A MoSi2-SiCp Composite by Reactive Sintering Without Pressure
    Zhang Xiaoli Lu Zhenlin Jin Zhihao
    2003(12):1037-1040.
    [Abstract](1212) [HTML](142) [PDF 0.00 Byte](9)
    Abstract:
    A MoSi2 SiC p composite was prepared by a reactive sintering without pressure. The results showed that a dense MoSi2 SiC p composite can not be made directly from the molybdenum and silicon powders reacted with carbon powder, but from the alloyed MoSi2 powder reacted with silicon and carbon powders. The strength and electrical resistivity of MoSi2 SiC p composite with various silicon carbide contents were measured and analysed at the same time. The results showed that the highest strength was 157 MPa and the electrical resistivity increased with the increase of SiC content.
    15  Ceramic Coatings Formed on Ti6Al4V Alloy by Micro-arc Oxidation in Na2SiO3-KOH- (NaPO3)6 Solution
    Wang Yaming Lei Tingquan Jiang Bailing Zhou Yu
    2003(12):1041-1044.
    [Abstract](1692) [HTML](116) [PDF 0.00 Byte](9)
    Abstract:
    用非平衡交流微弧氧化法于Na2SiO3-KOH-(NaPO3)6溶液中在Ti6Al4V表面形成氧化物陶瓷膜。分别用扫描电镜、电子探针及X射线衍射研究了陶瓷膜的组织形貌、元素分布和相组成。相对致密均匀的膜层主要由TiO2(钙钛矿相及金红石相)及非晶相组成。厚约20μm的膜可分为3层:过渡层、致密层与疏松层。电解液所含元素Si,P进入到膜层中,表明电解液组元急烈参与微弧氧化反应,这为通过选择电解液来设计膜层的相组成进而对膜层进一步改性提供途径。
    16  Deformation Behavor of Hydride in Zircaloy-4
    Wang Ruihong Ding Xiangdong Liu Gang Xiao Lin Sun Jun
    2003(12):1045-1048.
    [Abstract](1413) [HTML](124) [PDF 0.00 Byte](0)
    Abstract:
    The morphology and deformation behavior of the clustered, scattered and isolated hydrides in recrystallized Zr 4 have been studied by in situ SEM. It is shown that the hydride can deform plastically together with the matrix at room temperature. The deformation behavior of hydrides depends on their morphology. The clustered hydrides fracture at relatively low strain levels while the sparse hydrides are more ductile and usually fracture at a quite large strain. The isolated hydride has the best deformation capability and is difficult to fracture.
    17  Interface Behavior and Joint Strength by TIG Arc Brazing for Titanium and Titanium Alloy
    Yu Zhishui Qi Kai Li Ruifeng Zhou Fangming Wu Mingfang Qian Yiyu
    2003(12):1049-1052.
    [Abstract](1392) [HTML](149) [PDF 0.00 Byte](11)
    Abstract:
    用Ti—Cu—Ni,Ti-Cr-Zr钎料在TIG电弧加热条件对TA2和Ti—6Al—4V钛合金进行钎焊。结果表明:用Ti—Cu—Ni钎料钎焊TA2和Ti—6Al—4V钛合金的搭接接头强度分别是418.3MPa和439.6MPa;用Ti—Cr—Zr钎料钎焊TA2和Ti—6Al—4V钛合金的搭接接头强度分别是575.2MPa和656.1MPa。对Ti-Cu-Ni钎料/母材界面分析认为固液异分化合物η相((Cu,Ni)Ti2)生成时呈笋状生长,嵌入钎缝对钎缝的强度提高有利。对Ti-Cr-Zr钎料/母材界面分析,认为主要是固溶体β-Ti(Cr)存在提高了钎缝强度。
    18  Investigation of Electrical Conductivity of Silver Tin Oxide Electrical Contact Materials Fabricated by Reactive Synthesis
    Chen Jingchao Sun Jialin Du Yan Zhou Xiaolong Gan Guoyou
    2003(12):1053-1056.
    [Abstract](1589) [HTML](134) [PDF 0.00 Byte](1)
    Abstract:
    Silver tin oxide(AgSnO2) was fabricated using the conventional powder metallurgy(PM) and a new reactive synthesis(RS) method. Electrical conductivity measurement and X ray diffraction analysis were carried out on bulk AgSnO2 microstructures were determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) on the bulk AgSnO2 and its cold drawn wire. The results show that SnO2 particles with finer size and fresh interface can be formed in silver matrix as a result of the fabrication of AgSnO2 electrical contact materials by reactive synthesis. micrometer size tin oxide particles were assembled from nanometer scale particles during the RS process. Compared to conventionally PM processed, AgSnO2 electrical contact materials those fabricated by the RS process have a higher conductivity. and workability as a result of a change of combination states of silver and tin oxide.
    19  Effect of Niobium Implantation on the Corrosion Resistance of Zircaloy-4
    Yu Renhong Bai Xinde Chen Xiaowen Jin Zhaoxiong
    2003(12):1057-1060.
    [Abstract](1355) [HTML](143) [PDF 0.00 Byte](12)
    Abstract:
    为了研究Nb离子注入对Zr-4合金电化学腐蚀性能的影响,对Zr-4合金试样表面进行不同剂量的Nb离子注入并测定其在1NH2SO4水溶液中的极化曲线,然后使用扫描电子显微镜(SEM)对极化实验后的试样表面形貌进行了观察。结果表明,Nb离子注入能够改善Zr-4合金的耐腐蚀性能,而且改善的程度与注入离子的剂量有关。同时使用X射线光电子能谱分析(XPS)对试样的表层成分和价态进行了分析,发现在注量为5×1016ion/cm2和1×1017ion/cm2的条件下,Nb和Zr在试样表层以Nb2O5和ZrO2的形式存在;而在注量为2×1017ion/cm2的条件下,则以Nb2O5,NbO和ZrO2的形式存在。

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