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Volume 0,Issue 3,2003 Table of Contents

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  • 1  Study on SiC Continuous Fibre Reinforced Titanium Composites
    Zhao Yongqing Zhou Lian Alain Vassel
    2003(3):161-163.
    [Abstract](1334) [HTML](156) [PDF 0.00 Byte](9)
    Abstract:
    采用SCS-6 SiC连续纤维和箔-纤维-箔法制备SiC长纤维增强的TC4和Ti40基复合材料,研究复合材料的微观组织结构,结果表明:采用925℃的固化工艺制备长纤维SiC/TC4 和SiC/Ti40复合材料是合适的;SiC/TC4和SiC/Ti40复合材料的界面反应层厚度分别为0.8μm和0.6μm,基体与纤维的界面结合良好,在SiC/Ti40复合材料两纤维间区域存在TiC析出物。
    2  Research on Numerical Simulation of Investment Casting Process for Gamma Titanium Aluminide Turbocharger
    Liang Zuojian Xu Qingyan Li Juntao Li Shiqiong Zhang Ji Liu Baicheng Zhong Zengyong
    2003(3):164-169.
    [Abstract](1502) [HTML](143) [PDF 0.00 Byte](16)
    Abstract:
    Considering the characteristics of centrifugal casting technology with investment shell, the mathematical model of solidification process of gamma titanium aluminide turbochargers was established, and the model for shrinking and feeding was deduced under the condition of centrifugal pressure. Then, temperature field and shrinkage defects of gamma titanium alunimide turbocharger with different technologies were simulated. The results showed that the temperature distribution could be calculated and the shrinkage defects could be predicted with the model, and the simulation results coincided with the experimental results quite well. It is indicated that the optimum process to remove shrinkage defects presented in the preceding paper is rational.
    3  Structure Development during Mechanical Alloying of Mo and Si Powders
    Ma Qin Wang Cuixia Xue Qunji
    2003(3):170-172.
    [Abstract](1273) [HTML](138) [PDF 0.00 Byte](0)
    Abstract:
    采用X射线衍射仪(XRD)和差热分析仪(DTA)研究了Mo-67at%Si元素混合粉末在中等强度的机械研磨(合金化)过程中的结构变化过程,结果表明,在中等强度的研磨过程中,β-MoSi2是初生相,且在随后的研磨过程中非晶化;在高研磨强度下生成α-MoSi2的量大于β-MoSi2,且α-MoSi2的含量随研磨时间的增加而增加,差热分析表明亚稳相β-MoSi2随温度的升高会向α-MoSi2转变。
    4  Structure Determination of Ca2KNa(PO4)2 with Wide-angle XRD
    Niu Jinlong Zhang Zhenxi Jiang Dazong
    2003(3):173-175.
    [Abstract](1420) [HTML](148) [PDF 0.00 Byte](1)
    Abstract:
    通过大角度的粉末X射线衍射测定了正磷酸钠钾钙[(Ca2KNa(PO4)2)]晶体陶瓷的晶格参数,分析化学纯度的碳酸钙,磷酸二氢钾、磷酸二氢钠按照2:1:1的摩尔比混合后于1300摄氏度高温反应4h,得到了组合符合Ca2KNa(PO4)2的正磷酸钠钾钙陶瓷,在10度-130度的2θ扫描角范围内,在室温下进行粉末X射线衍射。测定结果显示,高温合成的Ca2KN2(PO4)2晶体相是α-CaKPO4和α-CaNaPO4晶体的高温固溶体,呈六方晶体结构,晶格参数为:α0=0.54396nm,C0=0.72976nm,晶胞体积V=0.187nm^3.
    5  Theoretical Explanation for Amorphous Phase Emerging Across the Interface during Explosive Welding
    Yan Honghao Li Xiaojie
    2003(3):176-178.
    [Abstract](1221) [HTML](148) [PDF 0.00 Byte](0)
    Abstract:
    A model for the temperature field across the interface during explosive welding has been proposed. The model can be used to analyze the reason of amorphous phase emerging on the interface during explosive welding, and the results can explain the phenomena as metioned above very well.
    6  Growth Characteristic of the Cruciform of TiB2 Needles
    Gao Wenli Zhang Hu He Jianping Jin Yunxue Zeng Songyan
    2003(3):179-182.
    [Abstract](1264) [HTML](138) [PDF 0.00 Byte](9)
    Abstract:
    用原位自生法制备了Ti-54Al-x B(at%)和Ti-50Al-x B(at%)合金并利用XRD和SEM对合金的相组成和微观组织进行了研究,结果表明:细棒状TiB2主要以数个或更多个呈族聚形式分布于晶界处,细棒状TiB2(1010}面存在与[0001]晶向垂直的薄片状凸耳;有些细棒状TiB2生长成垂直交叉状的简单十字形或“T”字形,族聚形式细棒状TiB2实际为三维空间较复杂的十字或“T”字形的复合形,研究还表明,细棒状十字形TiB2晶体的这种结果与其{1010}面上的生长台阶有关。
    7  The Hot Cracking Mechanism of 316L Stainless Steel Cladding in Rapid Laser Forming Process
    Chen Jing Lin Xin Wang Tao Yang Haiou Huang Weidong
    2003(3):183-186.
    [Abstract](1393) [HTML](144) [PDF 0.00 Byte](0)
    Abstract:
    The forming mechanism for the crack produced in the process of laser forming 316L stainless steel powder alloy has been studied in the paper by micro measurements. The results show that the cladding cracks were formed in grain boundary with dendritic structure commonly and presented a characteristic of cracking along grains. There was obvious oxidation color on the fracture section of the cracks. SEM photos show that the orientation and profile of dendrite grains are distinct and the dendrites are rather round on the crack surface. All these show that the cracks were formed at high temperature. The crack formed in the cladding layers is the solidification crack, which belongs to the domain of hot crack, mainly due to the separation of the liquid films in the grain boundary under the action of tension stress existed in the cladding layers which was produced in RLF process.
    8  Thermodynamic Analysis for the Reaction of Liquid Uranium and Its Alloys with Coatings of Graphite Crucibles
    Zhang Xian Cheng Laifei Zhang Litong Xu Yongdong
    2003(3):187-190.
    [Abstract](1485) [HTML](145) [PDF 0.00 Byte](12)
    Abstract:
    利用热力学计算,分析了一些材料在高温下与金属铀及铀合金反应的可能性,得到了这些反应ΔG°与温度的关系图。通过比较和分析这些材料对铀及铀合金熔体在高温下的化学稳定性,发现氧化钇对金属铀和铀合金熔体的化学稳定性最好,为熔铸金属铀和铀合金的石墨坩埚理想涂层材料。
    9  High-frequency Induction for Surface Alloying of Magnesium Alloy ZM5 and Its Corrosion Behavior
    Ma Youping Lu Xuzhong Xu Kewei
    2003(3):191-193.
    [Abstract](1266) [HTML](138) [PDF 0.00 Byte](15)
    Abstract:
    采用高频感应对ZM5镁合金表面进行合金化改性处理,并对改性层组织和腐蚀行为进行了研究,结果表明,镁合金经高频感应表面合金化改性处理,表层区域具有几乎连续的β-(Mg17Al12)相的细化晶粒区,认为这种均匀连续的β相将外部环境与镁的合金中的α相隔离,从而使镁合金的腐蚀速率降低。
    10  TG Analysis of Non Isothermal Oxidation Behaviors of Ni in PSZ Ni Composites
    Li Mingwei Zhu Jingchuan Yin Zhongda Zeng Gang
    2003(3):194-196.
    [Abstract](1148) [HTML](133) [PDF 0.00 Byte](9)
    Abstract:
    采用粉末冶金法制备出PSZ-Ni系复合材料,对不同组成的复合材料在20℃-1200℃升温氧化过程进行了TC分析。结果表明,金属Ni组元的氧化程度随陶瓷组元的增加而增加,且高温时更加严重,其原因主要是:一方面PSZ具有较高的导氧率导致氧向材料内部迅速扩散;另一方面,大量的金属-陶瓷界面大大缩短了氧的扩散途径;PSZ高的导氧率以及金属(陶瓷)是呈颗粒分散存在,使金属的表面积大大增加导致金属相氧化加剧。
    11  Microstructure and Corrosion Resistance of Laser Clad Coating of Ni2Si/Ni3Si2 Silicide Alloy
    Wang Chunmin Cai Liangxu Wang Huaming
    2003(3):197-200.
    [Abstract](1839) [HTML](146) [PDF 0.00 Byte](13)
    Abstract:
    A corrosion resistant Ni2Si/Ni3Si2 silicide alloy coating was fabricated on a substrate of low carbon steel A3 by laser cladding of the Ni76Si24 alloy powders. The laser clad silicide alloy coating has a rapidly solidified homogeneous microstructure consisting of plate like Ni2Si primary phase and minor amount of Ni2Si/Ni3Si2 eutectics and is metallurgically bonded to the steel substrate. The corrosion resistances of the silicide alloy coating in the water solutions of 0.5mol/l H2SO4 and 3.5% NaCl were evaluated utilizing the electrochemical polarization corrosion test method. Because of the inherent excellent corrosion resisting properties of the constituting phases Ni2Si and Ni3Si2, and the rapidly solidified homogeneous microstructure, the laser clad Ni2Si/Ni3Si2 silicide alloy coating exhibits excellent corrosion resistance.
    12  Electrochemical Characteristics and Sintering Preparation of Metal Hydride Electrode for Air MH Semi fuel Cell Applications
    Jiang Jianjun
    2003(3):201-204.
    [Abstract](1207) [HTML](138) [PDF 0.00 Byte](2)
    Abstract:
    The powder sintered technology for manufacturing thick metal hydride electrodes has been extensively investigated. A slurry consisting of hydrogen storage alloy powder mixed with fine nickel powder and some additives was pasted onto the nickel foam as a current collector. By choosing adjustable sintering parameters, the composite metal hydride electrode was obtained. The effects of sintering parameters on the electrochemical properties of sintered metal hydride electrode have been characterized. The results showed that the activation and high rate discharge ability were greatly improved and comparable to that obtained with conventional pasting process for sintered hydride electrode. In order to design the thick metal hydride electrode Suitable for the oxygen diffusion electrode of airmetal hydride semi fuel cell, the electrochemical characteristics of thick metal hydride electrode were comparativly studied for different metal substrates, suchas perforated nickel strip, perforated copper foil and copper mesh. As a consequence, the thick metal hydride electrode employing the perforated copper foil as a current collector has been evaluated to be suitable for the airmetal Hydride semi fuel cell.
    13  New Lubricating Coat for Cold Drawing of Titanium Alloy
    Yu Zhentao Yang Lin Wu Weilu Li Dong Deng Ju
    2003(3):205-208.
    [Abstract](1288) [HTML](138) [PDF 0.00 Byte](0)
    Abstract:
    A kind of new type lubricating coat for cold drawing of titanium alloy was developed with chemical method. The coat with grey black color possesses strong bonding force with titanium alloy matrix, and is mainly composed of Na3TiOF5.The tensile frication resistance forces are greatly reduced and the surface reality of titanium is improved when this kind of coat was applied with the mixed solid lubricants of graphite and MoS2 .
    14  Factors Affecting the Room Temperature Tensile Properties of TiAl Alloys with Fully Lamellar Microstructures
    Tang Jiancheng He Yuehui Liu Wensheng Zhou Kechao Zhang Junhong Lu Shiqiang Huang Baiyun
    2003(3):209-212.
    [Abstract](1365) [HTML](138) [PDF 0.00 Byte](10)
    Abstract:
    The effects of the microstructure and the strain rate on the room temperature tensile properties of Ti 47Al 2Cr(at%) with fully lamellar microstructures were investigated. It is shown that the room temperature tensile strength and ductility increase with the decrease of colony size and lamellar spacing. The room temperature tensile strength increases with the increase of strain rate. The room temperature ductility of low ductility alloy is not sensitive to strain rate, but the ductility of high ductility alloy is sensitive and increases with the increase of the strain rate.
    15  The Main Factors on Heat Conductivity for Carbon Carbon Composites
    Yu Shu Liu Genshan Li Xibin Xiong Xiang
    2003(3):213-215.
    [Abstract](1369) [HTML](147) [PDF 0.00 Byte](11)
    Abstract:
    This paper focuses on the main factors on heat conductivity for carbon carbon composites: the orientation of the carbon fiber; the temperature of heat treatment and the microstructure of the pyrolytic carbon matrix. The results show that it is the CVD pyrolytic carbon that determines the heat conductivity of carbon carbon composites, and the effect of heat treatment temperature is limited. The results also show that the CVD pyrolytic carbon that has high concentration of RL has high heat conductivity.
    16  Effect of Irradiation with Intense Pulsed Ion Beams on the Phase Evolution of Ni3Al Based Superalloy IC6
    Zhang Hongtao Wang Tianmin Wang Cong Wang Wenjun Han Baoxi Yan Sha Zhao Weijiang Han Yafang
    2003(3):216-219.
    [Abstract](1376) [HTML](136) [PDF 0.00 Byte](9)
    Abstract:
    对定向凝固Ni3Al基超合金IC6,以不同功率密度的强脉冲离子束进行照射,利用X射线衍射分析,研究了辐照后材料表面所产生的物相变化,结果表明:当以低功率密度辐照时,材料表面形成形变织构;随着功率密度的增加,材料表面还会发生部分非晶化,当功率密度进一步增加时,材料表面出现了新相。
    17  Hydrogen Storage Properties of Ti1.2Fe+x%Mg(x=1,3,5)alloys
    Xu Haiou Chen Changpin Wang Wei Cai Guanming Chen Lixin
    2003(3):220-223.
    [Abstract](1436) [HTML](135) [PDF 0.00 Byte](8)
    Abstract:
    The hydrogen storage properties of Ti1.2Fe+xwt%Mg(x=1,3,5) alloys have been investigated. The results show that the modified alloys can be activated at room temperature without any thermal treatment because of the addition of Mg and excess stoichiomentriy of Ti in alloys. The alloy Ti1.2Fe+3wt%Mg(Ti1.2FeMg0.12)is comparatively light in weight and has a large storage capacity,attaining 1.9wt%H2(213 ml/g),and small pressure hysteresis, so suitable for the hydrogen storage system with portable hydrogen fuel cell power. In the paper, the influence and mechanism of the addition of Mg and excessive Ti on the activation behavior and hydrogen storage capacity for the alloys have also been discussed.
    18  Study on the Joining Process of SiC and the Reaction Products of Filler
    Zhang Li Li Shujie Zhang Jianjun Ji Xiaoqiang Zhang Yan
    2003(3):224-227.
    [Abstract](1360) [HTML](144) [PDF 0.00 Byte](0)
    Abstract:
    采用热压反应烧结技术,使用Ti-Ni混合金属粉末焊料对SiC陶瓷进行连接,探讨了焊接温度、保温时间、焊料厚度以及焊接压力等工艺参数对连接件抗弯强度的影响规律,并通过对连接界面及焊料反应产物进行SEM,EDS,XRD分析,进一步考察了焊接工艺对连接件的断裂类型,焊料反应产物及其结合强度的影响规律。结果表明,采用适当的连接工艺,Ti-Ni焊料与母材可通过适当且适度的界面反应获得牢固结合,此时界面反应产物为以TiC,NiTi为主含Ni3C,Ni16Ti6Si7的混合物,且具有较高强度的TiC以弥散相形式分布在以具有一定韧性的金属间化合物NiTi为主的基质中,对接头性能的改善起到关键作用。在本实验范围内,在连接温度1100摄氏度,保温时间20min,焊接压力12.7MPa,焊料厚度0.3mm条件下可获得最佳陶瓷接头,其相对抗弯强度为53%。
    19  Properties and Applications of Ceramic Materials for Hot Extrusion Dies
    Liu Jun Zhou Fei
    2003(3):232-235.
    [Abstract](1173) [HTML](139) [PDF 0.00 Byte](0)
    Abstract:
    分析了β'Sialon和Ce-TZP陶瓷热挤压模的力学性能,并与3Cr2W8V模具钢热挤压模进行对比试验。结果表明:2种陶瓷热挤压模的使用寿命均明显高于3Cr2W8V热作模具钢热挤压量;β'Sialon陶瓷热挤压模的使用温度明显高于Ce-TZP陶瓷热挤压模的使用温度。
    20  Sapphire Joining Using Ag70.5Cu27.5Ti2 Brazing Filler Metal
    Ning Honglong Huang Fuxiang Ma Jusheng Geng Zhiting Han Zhongde
    2003(3):236-239.
    [Abstract](1130) [HTML](128) [PDF 0.00 Byte](0)
    Abstract:
    在845℃-860℃,6min的真空条件下,采用AgCuTi焊料封接蓝宝石与热等静压99%氧化铝,研究了AgCuTi焊料与蓝宝石界面的反应机理,同时对影响封接结合强度与气密性的因素-氧化铝的表面状况和焊接后的退火进行了分析,得出了控制焊接质量的处理方法。

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