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Volume 0,Issue 5,2002 Table of Contents

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  • 1  Synthesis of Low-dimensional Nano-structural GaN
    Li Zhenjiang Li Hejun Chen Xiaolong Li Kezhi Cao Yongge Li Jianye
    2002(5):321-324.
    [Abstract](1485) [HTML](137) [PDF 0.00 Byte](10)
    Abstract:
    氮化镓是宽的直接带隙半导体材料,由于其优异的性能,使之成为制作耐高温,大功率,低能耗电子器件,高速场效应晶体管,高效蓝光发光二极管(LED),激光二极管(LD)和紫外光电导探测器等光电子器件的理想材料,低维GaN纳米材料在基础理论研究和纳米技术应用等方面都具有巨大潜力,因此,近年来低维GaN纳米材料的制备和物性研究已成为热点之一,本文报道了低维GaN纳米材料的最新制备方法的研究进展。
    2  Fabrication of Nanometer Powders by the Sol-Gel Method
    Yao Minqi Wei Yinghui Hu Lanqing Xu Bingshe
    2002(5):325-329.
    [Abstract](1495) [HTML](142) [PDF 0.00 Byte](0)
    Abstract:
    The Sol-Gel (S-G) method is a moderate temperature process for prepa ring nanomaterials. In this paper, we discuss the principle of the S-G method, problems associated with it, as well as the hydrolysis characteristics of inor ganic compounds and metal alkoxides. By way of case study we consider the S-G p rocessing SnO2. We also go on to consider the future of the S-G method.
    3  Grain Morphology of YBCO Coated Superconductors Preparedby the Spin and Printing Process on Ni Substrates
    Liu Chunfang Du Shejun Wu Xuan Pang Ying Wang Feiyun Liu Xianghong Feng Yong Zhang Pingxiang Wu Xiaozu Zhou Lian
    2002(5):330-333.
    [Abstract](1155) [HTML](143) [PDF 0.00 Byte](0)
    Abstract:
    在金属Ni基带上,用旋转匀胶(spin)和刷涂(printing)工艺制备了具有c轴择优取向的YBCO厚膜,厚膜表面晶粒呈菊花和多边形状,菊花尺寸在0.2-0.5mm左右,最大尺寸达到1mm以上,多边形状晶粒常处在菊花的中心位置,MPMP(改进的粉末熔化工艺粉)试样中主要出现菊花状晶粒,多边形状晶粒基本不出现,PMP(粉末熔化工艺粉)试样中2种形貌晶粒一般同时存在。添加中间层(Ag)之后,菊花状晶粒消失或变得很不明显,X射线衍射分析表明,试样主要由Y123相组成并具有一定的C轴择优取向。
    4  Numerical Simulation of Solidification under Pulsed Magnetic Fields
    Zi Bingtao Yao Kefu Wang Hui Liu Wenjin Cui Jianzhong Xu Guangming Ba Qixian
    2002(5):334-336.
    [Abstract](1277) [HTML](132) [PDF 0.00 Byte](12)
    Abstract:
    用ANSYS有限元软件对脉冲磁场作用下,LY12铝合金凝固过程中的速度场作了数值模拟,模拟结果和实验现象相吻合,通过数值模拟发展,用数值模拟方法不仅可以初步了解凝固过程中熔体的运动状态,而且还可以了解凝固组织细化和产生缺陷的原因,是一个值得注意的研究方向,因此有较大的实用价值。
    5  Determination of an Isothermal Section of the Nb-Ti-Si Ternary System at 1 473 K
    Wang Richu Liu Chunlei Wang Chong Jin Zhanpeng
    2002(5):337-340.
    [Abstract](1530) [HTML](132) [PDF 0.00 Byte](0)
    Abstract:
    The diffusion triple technique is an advanced and efficient method for determining ternary phase diagrams. Phase equilibria in the Nb-Ti-Si ternary system at 1 473 K was investigated using diffusion triple technique and electron microprobe analysis (EMPA). The experimental results indicated that seven diffu sion layers (viz. TiSi2, TiSi, Ti5Si4, Ti5Si3, Nb5Si3, NbSi2 and M3Si) exist in the Nb-Ti-Si ternary system at 1 473 K, and that no ternary compound was obser ved in this diffusion triple. A tentative isothermal section of this system at 1 473 K was constructed on the basis of experimental data. The isothermal section consists of seven three-phase regions.
    6  Study of Simultaneous Strengthening and Toughening of Unsaturated Polyester Resin (TiO_2/UPR) by Nanometer TiO_2
    Xu Ying Li Mingli Lu Fengji
    2002(5):341-344.
    [Abstract](1164) [HTML](138) [PDF 0.00 Byte](0)
    Abstract:
    用“反应法”制备纳米TiO2/UPR,在反应过程中纳米TiO2粉发生轻微水解反应,产生的羟基与不饱和聚酯中的羧基反应,成功地将纳米TiO2粒子接入不饱和聚酯长链,这种新的结构实现了对不饱和聚酯同时增强增韧改性,纳米TiO2/UPR弯曲强度和冲击强度较UPR分别提高了55%和46%,当纳米TiO2含量从1%增加至10%时,发现纳米TiO2/UPR有明显的脆-韧转变现象,纳米TiO2含量6%时为脆-韧转变点。
    7  Composition and Phase Structure of Microarc Oxidation Coatings Deposited on TA_2 Pure Titanium
    Xue Wenbin Wang Chao Ma Hui Xie Mengxia Chen Ruyi Deng Zhiwei
    2002(5):345-348.
    [Abstract](1566) [HTML](159) [PDF 0.00 Byte](0)
    Abstract:
    采用交流微弧氧化方法,在铝酸盐溶液中的TA2纯钛表面沉积一层厚度达30μm的氧化物陶瓷膜,并用扫描电镜(SEM),能谱仪(EDS),X射线衍射(XRD),Raman光谱研究了氧化膜的成分和相结构,研究表明:该氧化膜具有内外两层结构,分别厚约15μm,氧化膜由TiAl2O5相和金红石型TiO2相组成,但外层膜里TiAl2O5相含量比内层膜里高得多,金红石则主要分布在膜内层里,来自溶液的铝原子已扩散到膜/钛基体界面,但膜外层的铝含量比内层高得多,微弧放电区瞬间高温高压过程对纯钛基体没有影响,Al,O原子都没有扩散进入未氧化的钛基体。
    8  An Atomic Scale Simulation on {100} Oriented CVD Diamond Film Grown under Modified Chemical Reaction Model
    An Xizhong Zhang Yu Liu Guoquon Qin Xiangge Wang Fuzhong Liu Shengxin
    2002(5):349-352.
    [Abstract](1358) [HTML](149) [PDF 0.00 Byte](11)
    Abstract:
    In this paper, the chemical reaction model in the growth of {100} orie nted CVD (chemical vapour deposition)diamond film is founded, and the growth mec hanisms of surface chemisorption are related to: (1) the BCN mechanism; (2) the dimer insertion; and (3) the trough insertion, in which the trough insertion mec hanism is in dominant. The growth process of (100) surface under this model is s imulated in atomic scale by using the modified KMC method, and the effect of sub strate temperature and CH3 concentration on film quality is provided. The result s show that this chemical reaction model can actually reveal the growth of {100} oriented CVD diamond film.
    9  Experimental Research on the Near Net Shape Casting Process of Gamma Tita nium Aluminide Turbochargers
    Liang Zuojian Xu Qingyan Li Juntao Zhang Ji Liu Baicheng Zhong Zengyon g
    2002(5):353-357.
    [Abstract](1286) [HTML](130) [PDF 0.00 Byte](17)
    Abstract:
    γ-TiAl金属间化合物的成形工艺是材料成形领域的前沿领域和研究热点,本研究采用水冷铜坩埚真空感应凝壳技术和熔模型壳离心浇注的铸造方法制备γ-TiAl增压涡轮,通过改善冒口工艺获得了健全的γ-TiAl涡轮铸件,分析了γ-TiAl增压涡轮的凝固过程和收缩缺陷产生原因,结果表明,增大冒口与然件的模数之差以及冒口与铸件的体积之比有利于减少及消除涡轮铸件的收缩缺陷,为给数值模拟研究提供热物性参数,针对涡轮铸件用钛铝合金,实验测试了合金的热膨胀系数,比热和热导率等物性参数,其与温度的关系分别为:α1=8.10651 0.0073T-2.97619E-6T^2,Cp=668.28158-0.013T 1.11905E-4T^2;λ=19.82252-0.02781T 6.5197E-5T^2-3.21096E-8T^3.
    10  Changes of Carbides Morphology in the Alloy Ti 15Al 7C during Heat Treatment
    Jin Yunxue Zeng Songyan Wang Hongwei
    2002(5):358-362.
    [Abstract](1205) [HTML](128) [PDF 0.00 Byte](7)
    Abstract:
    用熔铸法制备了TiCp/Ti-15Al复合材料,并通过SEM,XRD,EDX等手段,对合金铸态及热处理态的相组成及碳化物形态进行了研究,结果表明:合金在β-Ti(1300℃)区域热处理时,TiC枝晶首先从根部溶断,并逐步成为颗粒状,在α-Ti- βTi TiC三相区(1100℃)域热处理时,TiC枝晶部分溶解成为秃枝状同时析出了大量板片Ti3AlC,均匀分布在基体中,(0001)a-Ti面与(111)Ti3AlC面的晶格错配度很小,可形成共格界面,因此{0001}a-Ti面的层错形成的ABC…堆垛层,可成为Ti3AlC的晶胚,Ti3AlC晶胚生长时会以自动分支的方式调节Ti3AlC片的厚度和片间距。
    11  Classification and Evaluation of Influence Factors for Measuring Uncertainty of Property of Micromechanics of Materials by Nanoindentation
    Zhao Zexiang Jiang Zhuangde Wang Hairong
    2002(5):363-366.
    [Abstract](1137) [HTML](142) [PDF 0.00 Byte](0)
    Abstract:
    在介绍纳米压入法微机械力学性能测量原理的基础上,提出了纳米压入法微机械材料力学性能测量不确定度的I,II类影响因素的观点,并将I类影响因素分为直接和间接影响因素,将II类影响因素分为主要影响因素和次要影响因素。在阐述由这些因素产生的测量不确定度的评价方法基础上,对单晶硅(111)体材的硬度和弹性模量进行了测量与评定,其硬度和弹性模量的评定结果分别为13.57GPa±0.85GPa和156.33GPa±7.85GPa。
    12  Preparation and Gas Sensitivity of Semiconductor Oxides bySolid-state Reaction at Room Temperature
    Niu Xinshu Xu Yajie Xu Jiaqiang
    2002(5):367-370.
    [Abstract](1475) [HTML](141) [PDF 0.00 Byte](12)
    Abstract:
    N-type semiconducting nanometer oxides including SnO2,In2O3,ZnO,an d Fe2O3 were prepared by solid state reaction with inorganic compounds at room t emperature. The phase composition and microstructure of the powders were studied by XRD and TEM. The results show that the complete solid state reaction was ach ievable at room temperature. The mean particle size of powder is below 100 nm. T he gas sensing characteristics of the pure powders were studied. The results sho w that sensors made from SnO2,In2O3 have a high sensitivity and selectivity to LPG and ethanol, while the sensors made from ZnO,Fe2O3 have relatively poor sen sitivity.
    13  Interface Reaction Mechanism of Joining Alumina to Kovarwith Ni-Ti Active Filler
    Zhang Chunguang Qiao Guanjun Jin Zhihao
    2002(5):371-374.
    [Abstract](1327) [HTML](132) [PDF 0.00 Byte](0)
    Abstract:
    基于部分液相瞬间连接工艺,采用Ni-Ti活性钎焊技术实现了高纯Al2O3陶瓷与可伐合金(4J33-Kovar)的气密性封接,采用微观组织分析,微区优分分析和X射线衍射分析等方法,研究了封接反应的微观机理,研究结果表明,氧化铝陶瓷中的氧扩散进入焊料中,在焊料/Al2O3界面形成了Ni2Ti4O反应层,厚度1μm-2μm,起到了陶瓷晶格到金属晶格的过渡作用。
    14  Effect of the Diffusion Annealing on Concentration Distributions ininterfacial Regions of Au/Ag-Cu/Cu-Ni-Zn Laminate Strips
    Meng Liang Zhang Lei Zhou Shiping Yang Futao Shen Qijie
    2002(5):375-378.
    [Abstract](1394) [HTML](145) [PDF 0.00 Byte](10)
    Abstract:
    研究了不同温度扩散处理条件下Au/Ag-Cu/Cu-Ni-Zn3层复合薄带材在 结合面区域的成分分面。结果表明:在Ag-Cu/Cu-Ni-Zn结合面区域,扩散温度升高可促使Ni,Zn的迁移,但对Cu的迁移无明显影响,在Au/Ag-Cu结合面区域,较高的扩散温度可使Au,Ag及Cu原子通过原始结合面迅速迁移而互溶,导致纯Au表层演变为Ag-Au-Cu合金层。
    15  Influence of Heating Rates on DoubleReversible Transformations in CuZnAlMnNiShape Memory Alloy
    Bai Yujun Lu Chengwei Xu Xiangang Geng Guili Yin Longwei
    2002(5):379-381.
    [Abstract](1284) [HTML](145) [PDF 0.00 Byte](0)
    Abstract:
    通过差示扫描量热技术研究了不同的加热速率对CuZnAlMnNi记忆合金中双可逆相变的影响,结果表明:快速加热抑制了X→M转变却有利于马氏体逆转变,使两个相变峰靠近,随着加速速率的降低,两个相变峰逐渐分离。
    16  Liquidus Semicontinuous Casting and Thixoforming of the Aluminum All oy A356
    Wang Ping Lu Guimin Cui Jianzhong
    2002(5):382-384.
    [Abstract](1392) [HTML](133) [PDF 0.00 Byte](10)
    Abstract:
    研究了液相线半连续铸造法制备A356铝合金半固态浆触变成形并经固溶时效处理后的组织与性能,结果表明,触变成形与热处理后的A356件,其σb值达到238MPa,δ5达到17%,此结果为液相线半连续铸造A356铝合金触变成形的深入研究奠定了基础。
    17  Influences of Rare Earth La3+ Substitution on Structure andMagnetic Properties of M-Type Strontium Ferrites
    Liu Xiansong Zhong Wei Gu Benxi Du Youwei
    2002(5):385-388.
    [Abstract](1279) [HTML](128) [PDF 0.00 Byte](11)
    Abstract:
    采用陶瓷工艺,制备了Sr1-xLaxFe12O19M型锶铁氧体,系统地研究了稀土La^3 取代Sr^2 对M型六角铁氧体的结构和磁性的影响,La^3 离子取代部分的Sr^2 离子能明显改善M型铁氧体的内禀磁性。
    18  Effect of the Deformation and Heat Treatment on the Decomposition of a Zr in Zr-Sn-Nb Alloys
    Li Qiang Liu Wenqing Zhou Bangxin
    2002(5):389-392.
    [Abstract](1222) [HTML](120) [PDF 0.00 Byte](0)
    Abstract:
    用透射电子显微镜研究了变形及热处理对Zr-Sn-Nb合金中β-Zr分解的影响,试样经750℃,0.5h处理快冷后,在晶界上形成块状的β-Zr,在晶粒内形成棒状的β-Zr,经1000℃,0.5h处理快冷后,在板条晶粒的晶界上形成层状的β-Zr,晶界上的β-Zr在560℃热处理时发生的分解,得到颗粒状的β-Nb(100nm-200nm),但晶内棒状的β-Zr并不发生分解,变形使β-Zr变得更不稳定,促进其分解时的成核,可以得到粒径更小(10nm-60nm)的β-Nb第二相,原来不易发生分解的晶内棒状β-Zr,经变形处理后也可以发生分解,为了在含Nb的合金中获得细小并且均匀分布的β-Nb第二相,坯料经过均匀化β相加热淬火后,在后续的成材加工过程中,不应在高于610℃的温度下进行热处理,要避免重新形成块状的β-Zr。
    19  A Themo-Control Valve Fabricated from Shape-Memory Alloy for Use in the Oil Field
    Yu Wuxing Lin Jun Wang Chunwu Xue Haihui Lin Renrong Geng Dianqi Wei Hairong
    2002(5):393-396.
    [Abstract](1231) [HTML](143) [PDF 0.00 Byte](0)
    Abstract:
    Heating and cooling curves for the double-memory-type shape memory a lloy (SMA) Cu-29 8 Zn-4Al have been measured. The microstructure of the allo y aged at various temperatures have been investigated using TEM. After analyzing properties of the alloy, the application parameters of a double-memory-type s pring formed from it were calculated. Based on the experimental data a themo-co ntrol valve for oil-field use was designed. The valve can switch on or off aut omatically. of simple construction, it functions reliably and is suitable for us e in critical situations .
    20  Effects of Heat Treatment on the Electrochemical Properties of theHydrogen Storage Alloy LPC(NiCoAlMn)_5.0)
    Li Jianwen Chen Yungui Tu Mingjing
    2002(5):397-397.
    [Abstract](1510) [HTML](149) [PDF 0.00 Byte](11)
    Abstract:
    The effects of heat treatment at 673 K, 1 173 K and 1 373 K on the ele ctrochemical properties of the hydrogen storage alloy LPC(NiCoAlMn)5 0, such as activity, discharge capacity and rate-of-discharge capacity, have been invest igated. The results show that the cycling stability and large discharging capaci ty are improved. The alloy heat treated at 1 173 K has good electrochemical prop erties.

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