Volume 36,Issue 4,2007 Table of Contents
Feng Jianqing
,
Zhou Lian
,
Lu Yafeng
,
Zhang Pingxiang
,
Xu Xiaoyan
,
Chen Shaokai
,
Zhang Cuiping
,
Xiong Xiaomei
,
Liu Guoqing
2007, 36(4):565-568.
Abstract:
The recent developments of additive effect of high-temperature oxide YBCO superconductors were reviewed. The critical current density and transition temperature were improved by chemical addition. The additive can improve the mechanical property and affect precursory powder thermal behavior of YBCO. The research of additive effect can improve applied properties of YBCO .and supply more informations for exploring mechanism of superconductors.
The recent developments of additive effect of high-temperature oxide YBCO superconductors were reviewed. The critical current density and transition temperature were improved by chemical addition. The additive can improve the mechanical property and affect precursory powder thermal behavior of YBCO. The research of additive effect can improve applied properties of YBCO .and supply more informations for exploring mechanism of superconductors.
2007, 36(4):569-572.
Abstract:
To forecast the properties of the HfC1-xNx solid solutions, their valence electron structures were analyzed and compared with those of the HfC and HfN matrix on the base of the empirical electron theory (EET) of solids and molecules. The results showed that, when the HfC and HfN dissolved each other, the step numbers of two nonmetallic atoms (C and N) were invariable, and the step number of Hf element increased form B11 to B16. With the x value increasing, the covalent electron amount and the bond energy on the strongest bond and the melting point, all dropped gradually, while the percentage of total covalent bond number increased, indicating that the hardness, bond energy, melting point and toughness decreased, and the strength increased.
To forecast the properties of the HfC1-xNx solid solutions, their valence electron structures were analyzed and compared with those of the HfC and HfN matrix on the base of the empirical electron theory (EET) of solids and molecules. The results showed that, when the HfC and HfN dissolved each other, the step numbers of two nonmetallic atoms (C and N) were invariable, and the step number of Hf element increased form B11 to B16. With the x value increasing, the covalent electron amount and the bond energy on the strongest bond and the melting point, all dropped gradually, while the percentage of total covalent bond number increased, indicating that the hardness, bond energy, melting point and toughness decreased, and the strength increased.
2007, 36(4):573-577.
Abstract:
The multi-phase field model of Nestler is used to simulate the free growth of isothermal binary eutectic and to study the growth mechanisms under different initial nucleation conditions, including the given quantity and morphology of nucleus and the stochastic nucleation. The variety of Avrami exponent calculated through the relationship between solid volume fraction and transition time demonstrates that there are three possible eutectic growth mechanisms, i.e. the diffusion limited growth, the lamellar growth and the spinodal decomposition growth. And the process of free eutectic growth is the transition process of the three growth mechanisms from one to another.
The multi-phase field model of Nestler is used to simulate the free growth of isothermal binary eutectic and to study the growth mechanisms under different initial nucleation conditions, including the given quantity and morphology of nucleus and the stochastic nucleation. The variety of Avrami exponent calculated through the relationship between solid volume fraction and transition time demonstrates that there are three possible eutectic growth mechanisms, i.e. the diffusion limited growth, the lamellar growth and the spinodal decomposition growth. And the process of free eutectic growth is the transition process of the three growth mechanisms from one to another.
2007, 36(4):578-582.
Abstract:
Plastic deformation of bulk metallic glass (BMG) Zr55Al10Ni5Cu30 was investigated by nanoindentation experiments at room temperature. The characters of plastic deformation were studied by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that the discrete shear bands are formed around the indent and the local free volume is increased in the bulk metallic glass by deformation. The mechanism governing the plastic deformation was discussed in terms of the free volume mode.
Plastic deformation of bulk metallic glass (BMG) Zr55Al10Ni5Cu30 was investigated by nanoindentation experiments at room temperature. The characters of plastic deformation were studied by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that the discrete shear bands are formed around the indent and the local free volume is increased in the bulk metallic glass by deformation. The mechanism governing the plastic deformation was discussed in terms of the free volume mode.
2007, 36(4):583-586.
Abstract:
采用动态蒙特卡罗（kinetic Monte Carlo，简称KMC）方法研究物理气相沉积（physical vapor deposition，简称PVD）制备Ni薄膜过程中入射角度对薄膜微观结构的影响。该KMC模型中既包括入射原子与表面之间的碰撞，又包括被吸附原子的扩散。模拟中用动量机制确定被吸附原子在表面上的初始构型，用分子稳态（molecular statics，简称MS）计算方法计算扩散模型中跃迁原子的激活能。对于模拟结果，采用表面粗糙度和堆积密度作为沉积构型评价指标。研究结果表明：当沉积速率是5μm／min，基板温度是300K和500K时，表面粗糙度和堆积密度曲线在入射角度等于35°时出现拐点；入射角度小于35°时，入射角度增大对表面粗糙度增加和堆积密度减小的影响很少；但是入射角度大于35°时，随入射角度增大表面粗糙度迅速增加、堆积密度迅速减小。另外，当基板温度是300K时，入射角度对薄膜微观结构的影响程度大于基板温度为500K时的影响程度。说明高基板温度促使原子更加充分地扩散，从而能削弱自阴影效应的作用。但是，在保证足够高基板温度和合理沉积速率的情况下，入射角度过大同样不利于致密结构形成。
采用动态蒙特卡罗（kinetic Monte Carlo，简称KMC）方法研究物理气相沉积（physical vapor deposition，简称PVD）制备Ni薄膜过程中入射角度对薄膜微观结构的影响。该KMC模型中既包括入射原子与表面之间的碰撞，又包括被吸附原子的扩散。模拟中用动量机制确定被吸附原子在表面上的初始构型，用分子稳态（molecular statics，简称MS）计算方法计算扩散模型中跃迁原子的激活能。对于模拟结果，采用表面粗糙度和堆积密度作为沉积构型评价指标。研究结果表明：当沉积速率是5μm／min，基板温度是300K和500K时，表面粗糙度和堆积密度曲线在入射角度等于35°时出现拐点；入射角度小于35°时，入射角度增大对表面粗糙度增加和堆积密度减小的影响很少；但是入射角度大于35°时，随入射角度增大表面粗糙度迅速增加、堆积密度迅速减小。另外，当基板温度是300K时，入射角度对薄膜微观结构的影响程度大于基板温度为500K时的影响程度。说明高基板温度促使原子更加充分地扩散，从而能削弱自阴影效应的作用。但是，在保证足够高基板温度和合理沉积速率的情况下，入射角度过大同样不利于致密结构形成。
2007, 36(4):587-591.
Abstract:
采用气态源分子束外延（GSMBE）技术优化生长了GaAs／AlAs分布布拉格反射镜（DBR）材料，并用X射线衍射（XRD）及反射光谱对其生长质量进行了表征。结果表明，采用5S间断生长的GaAs／AlAs DBR材料质量和界面质量优于无间断生长，并且10对GaAs／AlAs DBR的质量优于30对，说明DBR对数越多，周期厚度波动越大，材料质量越差。优化生长得到的30对GaAs／AlAsDBR的反射率大于99％，中心波长为1316nm，与理论设计结构的模拟结果基本一致，可用作1．3μm垂直腔面发射激光器（VVSEL）直接键合的反射腔镜。
采用气态源分子束外延（GSMBE）技术优化生长了GaAs／AlAs分布布拉格反射镜（DBR）材料，并用X射线衍射（XRD）及反射光谱对其生长质量进行了表征。结果表明，采用5S间断生长的GaAs／AlAs DBR材料质量和界面质量优于无间断生长，并且10对GaAs／AlAs DBR的质量优于30对，说明DBR对数越多，周期厚度波动越大，材料质量越差。优化生长得到的30对GaAs／AlAsDBR的反射率大于99％，中心波长为1316nm，与理论设计结构的模拟结果基本一致，可用作1．3μm垂直腔面发射激光器（VVSEL）直接键合的反射腔镜。
2007, 36(4):592-596.
Abstract:
基于动态材料模型（DMM），建立了Ti2AlNb基合金（Ti-22Al-25Nb）在温度94012-1060℃，应变速率0．001s^-1-10s^-1范围内的加工图，并利用该图分析了合金的高温变形特性。结果发现：在温度94012～97012，应变速率0．4s^-1～10s^-1和温度970℃—1060℃，应变速率1s^-1～10s^-1范围为流动失稳区，前者范围内主要发生绝热剪切变形和45°角剪切开裂，功率耗散率达到最小值；后者区域内以局部塑性流动和纵向开裂为主，功率耗散率小于33％。热加工图的其余部分为塑性加工的“安全区”，主要发生再结晶。在温度94012～970℃，应变速率0．001s^-1-0．4s^-1范围，以α2／O相板条球化为主；在温度970℃～1030℃，应变速率0．001s^-1～1S^-1范围，功率耗散率为35％-45％，呈现连续再结晶特征。在温度1030℃～1060℃。麻蛮谏率0．001s^-1-0.1s^-1范围。功率耗散率为45％～66％。达最大值,发生连续再结晶晶粒长大。
基于动态材料模型（DMM），建立了Ti2AlNb基合金（Ti-22Al-25Nb）在温度94012-1060℃，应变速率0．001s^-1-10s^-1范围内的加工图，并利用该图分析了合金的高温变形特性。结果发现：在温度94012～97012，应变速率0．4s^-1～10s^-1和温度970℃—1060℃，应变速率1s^-1～10s^-1范围为流动失稳区，前者范围内主要发生绝热剪切变形和45°角剪切开裂，功率耗散率达到最小值；后者区域内以局部塑性流动和纵向开裂为主，功率耗散率小于33％。热加工图的其余部分为塑性加工的“安全区”，主要发生再结晶。在温度94012～970℃，应变速率0．001s^-1-0．4s^-1范围，以α2／O相板条球化为主；在温度970℃～1030℃，应变速率0．001s^-1～1S^-1范围，功率耗散率为35％-45％，呈现连续再结晶特征。在温度1030℃～1060℃。麻蛮谏率0．001s^-1-0.1s^-1范围。功率耗散率为45％～66％。达最大值,发生连续再结晶晶粒长大。
8 The Study of Deformation and Damage Mechanism of Aluminum Alloy (6063) under Different Stress States
2007, 36(4):597-601.
Abstract:
利用改装的Arcan夹具对铝合金（6063）的蝶形试样进行0°，30°，45°，60°，90°的拉伸及拉伸卸载试验，研究了铝合金在不同应力状态下变形及损伤机理。结果表明：铝合金在不同应力状态下的工程应力一应变曲线明显不同。0°加载时，在蝶形中心产生微孔洞，微孔洞之间剪切，从而产生了微裂纹。随着微裂纹的扩展、连接导致试样断裂。随着试样中三轴应力度的减小，在蝶形试样中心的剪切应力不断增大，同时在蝶形试样中的剪切变形带越来越集中。显微裂纹首先在剪切带中产生，随着微裂纹的扩展导致试样的断裂。90°拉伸时，在蝶形中心形成明显的剪切变形带。90°加载时，在试样中产生的剪切带是形变剪切带而非相变剪切带。利用有限元软件ABAQUS对不同角度拉伸试验进行模拟，从而得出了不同应力状态下的塑性区的形状和大小。
利用改装的Arcan夹具对铝合金（6063）的蝶形试样进行0°，30°，45°，60°，90°的拉伸及拉伸卸载试验，研究了铝合金在不同应力状态下变形及损伤机理。结果表明：铝合金在不同应力状态下的工程应力一应变曲线明显不同。0°加载时，在蝶形中心产生微孔洞，微孔洞之间剪切，从而产生了微裂纹。随着微裂纹的扩展、连接导致试样断裂。随着试样中三轴应力度的减小，在蝶形试样中心的剪切应力不断增大，同时在蝶形试样中的剪切变形带越来越集中。显微裂纹首先在剪切带中产生，随着微裂纹的扩展导致试样的断裂。90°拉伸时，在蝶形中心形成明显的剪切变形带。90°加载时，在试样中产生的剪切带是形变剪切带而非相变剪切带。利用有限元软件ABAQUS对不同角度拉伸试验进行模拟，从而得出了不同应力状态下的塑性区的形状和大小。
2007, 36(4):602-606.
Abstract:
采用粉末冶金＋热挤压工艺制备SiCp/Al复合材料，测定其力学性能。利用X射线衍射分析复合材料物相的组成，用金相显微镜、扫描电镜和透射电镜分析其微观组织结构。结果表明，SiC颗粒在铝基体中分布比较均匀，SiC颗粒与基体结合良好；基体主要是α-Al，强化相β-Mg2Si和弥散相（Fe，Mn，Cu）3Si2Al15（体心立方结构，晶格常数1．28nm）；SiCp／Al界面则为Al和Mg元素扩散到SiC表面的SiO2层形成的20nm-30nm无定形层；复合材料的断裂机制主要是SiC颗粒断裂和SiCp／Al界面塑性撕裂：复合材料在变形过程中，SiC颗粒可阻止裂纹的扩展。
采用粉末冶金＋热挤压工艺制备SiCp/Al复合材料，测定其力学性能。利用X射线衍射分析复合材料物相的组成，用金相显微镜、扫描电镜和透射电镜分析其微观组织结构。结果表明，SiC颗粒在铝基体中分布比较均匀，SiC颗粒与基体结合良好；基体主要是α-Al，强化相β-Mg2Si和弥散相（Fe，Mn，Cu）3Si2Al15（体心立方结构，晶格常数1．28nm）；SiCp／Al界面则为Al和Mg元素扩散到SiC表面的SiO2层形成的20nm-30nm无定形层；复合材料的断裂机制主要是SiC颗粒断裂和SiCp／Al界面塑性撕裂：复合材料在变形过程中，SiC颗粒可阻止裂纹的扩展。
2007, 36(4):607-611.
Abstract:
The influence of trace Zr on the quench sensitivity of 7055 type aluminum alloy was investigated by ambient tensile testing, optical microscopy(OM), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The results showed that the addition of trace Zr increased the quench sensitivity for the strength of alloy, but decreased the quench sensitivity for elongation, especially when the Zr amount was not less than 0.1%. The recrystallization occurred in the Zr-containing alloy not only increased the amount of random high angle grain boundaries, but made Al3Zr dispersoids losing the coherency with the matrix. As a result, the nucleation sites increased for heterogeneous precipitation during slow quenching, and the quench sensitivity of strength increased. The reasons for the decreased quench sensitivity of elongation were mainly due to the inhibition of recrystallization and the grain refining effect by Zr adding.
The influence of trace Zr on the quench sensitivity of 7055 type aluminum alloy was investigated by ambient tensile testing, optical microscopy(OM), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The results showed that the addition of trace Zr increased the quench sensitivity for the strength of alloy, but decreased the quench sensitivity for elongation, especially when the Zr amount was not less than 0.1%. The recrystallization occurred in the Zr-containing alloy not only increased the amount of random high angle grain boundaries, but made Al3Zr dispersoids losing the coherency with the matrix. As a result, the nucleation sites increased for heterogeneous precipitation during slow quenching, and the quench sensitivity of strength increased. The reasons for the decreased quench sensitivity of elongation were mainly due to the inhibition of recrystallization and the grain refining effect by Zr adding.
2007, 36(4):612-616.
Abstract:
分别采用光学显微镜、扫描电子显微镜、X射线衍射和显微硬度等测试手段，研究了激光快速成形高强高韧损伤容限型TC21钛合金的沉积态组织。结果表明：TC21沉积态有着粗大的沿沉积高度方向外延生长的原始声柱状晶，仅最后一层熔覆层顶部为较细小的声等轴晶。宏观上存在明暗两个组织区域，明区为针状马氏体区，位于最后十几层熔覆层，暗区为网篮组织区。结合成形过程传热和组织转变理论分析认为，网篮组织是由明区的初始快冷凝固的马氏体在成形过程中，经受再热循环的固溶时效作用转变而来。随着激光功率的增大，原始声柱状晶将粗化，暗区网篮组织中片状口亦将长大；明区硬度基本不变，暗区硬度略有下降。
分别采用光学显微镜、扫描电子显微镜、X射线衍射和显微硬度等测试手段，研究了激光快速成形高强高韧损伤容限型TC21钛合金的沉积态组织。结果表明：TC21沉积态有着粗大的沿沉积高度方向外延生长的原始声柱状晶，仅最后一层熔覆层顶部为较细小的声等轴晶。宏观上存在明暗两个组织区域，明区为针状马氏体区，位于最后十几层熔覆层，暗区为网篮组织区。结合成形过程传热和组织转变理论分析认为，网篮组织是由明区的初始快冷凝固的马氏体在成形过程中，经受再热循环的固溶时效作用转变而来。随着激光功率的增大，原始声柱状晶将粗化，暗区网篮组织中片状口亦将长大；明区硬度基本不变，暗区硬度略有下降。
2007, 36(4):617-620.
Abstract:
采用垂直向下的高梯度定向凝固装置，研究了有热溶质对流的Al-38．5％Cu（质量分数，下同）过共晶合金中定向凝固组织变化。结果表明：热溶质对流造成界面前沿的溶质成分（Cu元素）沿轴向减少。在定向凝固速率为5μm／s，合金溶质成分减少到37％Cu以下时，合金定向凝固组织中，初生θ-Al2Cu相会消失，组织变为全耦合生长的共晶组织。合金凝固的固相分数（fs）≥0．49时，组织变为全耦合生长共晶组织所对应的溶质成分的理论计算结果与实验结果相吻合。
采用垂直向下的高梯度定向凝固装置，研究了有热溶质对流的Al-38．5％Cu（质量分数，下同）过共晶合金中定向凝固组织变化。结果表明：热溶质对流造成界面前沿的溶质成分（Cu元素）沿轴向减少。在定向凝固速率为5μm／s，合金溶质成分减少到37％Cu以下时，合金定向凝固组织中，初生θ-Al2Cu相会消失，组织变为全耦合生长的共晶组织。合金凝固的固相分数（fs）≥0．49时，组织变为全耦合生长共晶组织所对应的溶质成分的理论计算结果与实验结果相吻合。
2007, 36(4):621-624.
Abstract:
采用Co基自熔合金＋块状WC混合粉末进行送粉激光熔覆并获得熔覆层，对熔覆层在不同温度下加热后空冷至室温，观察相应熔覆层的显微组织变化。结果表明：熔覆层850℃再加热处理，可以实现去应力退火的目的。Co基自熔合金基体的显微组织在850℃以上开始不稳定，当受到高于此温度冲击时，发生形态和显微组织结构的变化。对熔覆层中的块状WC进行再加热，当加热温度达到1000℃以上时，块状WC会发生离散，分化成细小的WC颗粒。产生这种现象的根本原因是块状WC具有先天的超细纤维、颗粒混合结构。
采用Co基自熔合金＋块状WC混合粉末进行送粉激光熔覆并获得熔覆层，对熔覆层在不同温度下加热后空冷至室温，观察相应熔覆层的显微组织变化。结果表明：熔覆层850℃再加热处理，可以实现去应力退火的目的。Co基自熔合金基体的显微组织在850℃以上开始不稳定，当受到高于此温度冲击时，发生形态和显微组织结构的变化。对熔覆层中的块状WC进行再加热，当加热温度达到1000℃以上时，块状WC会发生离散，分化成细小的WC颗粒。产生这种现象的根本原因是块状WC具有先天的超细纤维、颗粒混合结构。
Liang Chenghao
,
Chen Bangyi
,
Su Linlin
,
Wu Bo State Key Laboratory of Fine Chemicals
,
Dalian University of Technology
,
Dalian
,
China)
2007, 36(4):625-628.
Abstract:
运用电化学方法对工业纯Ti，Ti6Al4V合金和TAMZ合金在人工唾液中的电化学行为进行了研究，探讨了溶液pH值对Ti合金电化学性能的影响。结果表明，在人工唾液中，TAMZ合金具有最佳电化学稳定性，腐蚀速率最低。Ti合金在人工唾液中存在较大的钝化区间，电化学稳定性按工业纯Ti，Ti6Al4V合金和TAMZ合金的顺序依次增强。随溶液pH值升高，试样的热力学稳定性增强。交流阻抗结果显示，3种实验材料在人工唾液中具有优异的耐蚀性能，腐蚀速率均在10^-2μm／a数量级，小于医用级标准0．25μm／a。
运用电化学方法对工业纯Ti，Ti6Al4V合金和TAMZ合金在人工唾液中的电化学行为进行了研究，探讨了溶液pH值对Ti合金电化学性能的影响。结果表明，在人工唾液中，TAMZ合金具有最佳电化学稳定性，腐蚀速率最低。Ti合金在人工唾液中存在较大的钝化区间，电化学稳定性按工业纯Ti，Ti6Al4V合金和TAMZ合金的顺序依次增强。随溶液pH值升高，试样的热力学稳定性增强。交流阻抗结果显示，3种实验材料在人工唾液中具有优异的耐蚀性能，腐蚀速率均在10^-2μm／a数量级，小于医用级标准0．25μm／a。
2007, 36(4):629-632.
Abstract:
In natural environment, tarnish was observed on the surface of a commemoration silver coin of China. In order to identify the nature of the tarnishing film, optical microscope(OM), scanning electron microscope(SEM), electron microprobe analyses(EMPA), X-ray photoelectron spectroscopy(XPS), and X-ray diffraction(XRD) were applied to examine the tarnishing areas. It was found that the tarnishing position is uniformly moderate brown and several dark brown spots are randomly distributed. Groups of corrosion holes are distributed over the forging stress zones formed in the struck process. As result of surface analyses using EMPA, sulfur and oxygen were detected besides silver with uniformity of sulfur. Furthermore, distributions of silver and oxygen were in correspondence with the morphology of dark brown spots. XPS and XRD showed that components of spots are Ag2S, Ag2O and Ag2SO3, with a predominance of the first one. It could be estimated that the tarnish of silver is a series of electrochemical process that requires the presence of sulfur and oxygen.
In natural environment, tarnish was observed on the surface of a commemoration silver coin of China. In order to identify the nature of the tarnishing film, optical microscope(OM), scanning electron microscope(SEM), electron microprobe analyses(EMPA), X-ray photoelectron spectroscopy(XPS), and X-ray diffraction(XRD) were applied to examine the tarnishing areas. It was found that the tarnishing position is uniformly moderate brown and several dark brown spots are randomly distributed. Groups of corrosion holes are distributed over the forging stress zones formed in the struck process. As result of surface analyses using EMPA, sulfur and oxygen were detected besides silver with uniformity of sulfur. Furthermore, distributions of silver and oxygen were in correspondence with the morphology of dark brown spots. XPS and XRD showed that components of spots are Ag2S, Ag2O and Ag2SO3, with a predominance of the first one. It could be estimated that the tarnish of silver is a series of electrochemical process that requires the presence of sulfur and oxygen.
2007, 36(4):633-635.
Abstract:
为了预测细晶钨合金用作穿甲弹的高剪切毁伤效应，采用机械合金化（MA）和喷雾干燥-热还原两种方法制备含稀土的超细93W-Ni-Fe-Y2O3复合粉末，利用冷等静压液相烧结的方法制备Ф20mm-Ф25mm的晶粒度小于8μm的钨合金棒材。利用Hopkinson压杆装置对细晶钨合金进行了高应变率（〉10^3／s）下的动态力学性能研究，分析了应变、应变率、Y2O3等因素对细晶钨合金棒材的动态性能的影响。结果表明：钨合金在高应变率下会出现应变强化和热软化效应，在低应变时应力随着应变的增加而增加，当应变达到0．03后，应力随着应变的增加呈锯齿状上升趋势。钨合金在高应变率下会出现应变率强化效应，随着应变率的增加，应力增加。添加Y2O能提高材料的最大应力强度，提高钨合金的动态力学性能。
为了预测细晶钨合金用作穿甲弹的高剪切毁伤效应，采用机械合金化（MA）和喷雾干燥-热还原两种方法制备含稀土的超细93W-Ni-Fe-Y2O3复合粉末，利用冷等静压液相烧结的方法制备Ф20mm-Ф25mm的晶粒度小于8μm的钨合金棒材。利用Hopkinson压杆装置对细晶钨合金进行了高应变率（〉10^3／s）下的动态力学性能研究，分析了应变、应变率、Y2O3等因素对细晶钨合金棒材的动态性能的影响。结果表明：钨合金在高应变率下会出现应变强化和热软化效应，在低应变时应力随着应变的增加而增加，当应变达到0．03后，应力随着应变的增加呈锯齿状上升趋势。钨合金在高应变率下会出现应变率强化效应，随着应变率的增加，应力增加。添加Y2O能提高材料的最大应力强度，提高钨合金的动态力学性能。
2007, 36(4):636-639.
Abstract:
The ion selective film of Nafion was used to modify the iridium oxide electrode, and it is found that the coated ion selective film on the electrode improves the resistance to the interference of oxidative/reductive negative ions. SEM was used to observe the pore size distribution on the surface and cross-section of the coated selective film on the electrode for the purpose of optimizing the preparation process of the film. Cyclic voltammetry experiment was carried out to study the electrochemical behavior of the Nafion-coated electrode. The ion selective mechanism is suggested based on the calculation of positive/negative ion transport coefficient, i. e. t+ and t-, using the method of film potential measurement.
The ion selective film of Nafion was used to modify the iridium oxide electrode, and it is found that the coated ion selective film on the electrode improves the resistance to the interference of oxidative/reductive negative ions. SEM was used to observe the pore size distribution on the surface and cross-section of the coated selective film on the electrode for the purpose of optimizing the preparation process of the film. Cyclic voltammetry experiment was carried out to study the electrochemical behavior of the Nafion-coated electrode. The ion selective mechanism is suggested based on the calculation of positive/negative ion transport coefficient, i. e. t+ and t-, using the method of film potential measurement.
2007, 36(4):640-643.
Abstract:
制备了高电导的La0．5Sr0.5CoO3块样，其800℃电导率为238S／cm。通过磁控溅射将La0.5Sr0．5CoO3涂覆在Fe-13Cr合金表面，再进行800℃等温氧化100h。SEM分析发现，Fe-13Cr基体中的Cr和Mn向涂层表面外扩散，同时涂层中的La，Sr及Co原子向合金基体内部扩散。电阻测试发现，氧化过程中，形成的反应层并没有显著降低试样的面电阻，800℃等温氧化100h后的面电阻为6mΩ·cm^2。
制备了高电导的La0．5Sr0.5CoO3块样，其800℃电导率为238S／cm。通过磁控溅射将La0.5Sr0．5CoO3涂覆在Fe-13Cr合金表面，再进行800℃等温氧化100h。SEM分析发现，Fe-13Cr基体中的Cr和Mn向涂层表面外扩散，同时涂层中的La，Sr及Co原子向合金基体内部扩散。电阻测试发现，氧化过程中，形成的反应层并没有显著降低试样的面电阻，800℃等温氧化100h后的面电阻为6mΩ·cm^2。
2007, 36(4):644-647.
Abstract:
Using pulsed laser deposition method, the La0.82Te0.18MnO3 thin film was prepared on LaAlO3 (012) single crystal substrate. The structure of the film studied by X-ray diffractometry shows that the film has perovskite pseudocubic structure, and is of preferential orientation (012). The R-T curves show the metal-insulator transition (MIT) and CMR effect. And the TMI are 283 K and 303 K for 0 T and 0.7 T, respectively, and they are both near room temperature. The maximum MR is 30.6% at 0.7 T. Correspondingly, the peak temperature at the maximum MR is 263 K. This shows that the films display CMR effect in the mental region. Moreover, the magnetoresistance ratio at the room temperature (303 K) is 4.8% at 0.7 T. The results show that the data satisfy R=P1+P2T2+P3T4.5 for TTMI, it is satisfied with small polaron model. The effect of the continuous wave laser (532 nm, 40 mW) on the film was also investigated. Below TMI, the resistance increased under photo inducing. Above TMI there was a decrease of the resistance. The maximum photoinduced resistance change is 33.6%. This is attributed to the change of the magnetic order in the film because of photoinducing, which might reduce the double exchange, and change electronic transport.
Using pulsed laser deposition method, the La0.82Te0.18MnO3 thin film was prepared on LaAlO3 (012) single crystal substrate. The structure of the film studied by X-ray diffractometry shows that the film has perovskite pseudocubic structure, and is of preferential orientation (012). The R-T curves show the metal-insulator transition (MIT) and CMR effect. And the TMI are 283 K and 303 K for 0 T and 0.7 T, respectively, and they are both near room temperature. The maximum MR is 30.6% at 0.7 T. Correspondingly, the peak temperature at the maximum MR is 263 K. This shows that the films display CMR effect in the mental region. Moreover, the magnetoresistance ratio at the room temperature (303 K) is 4.8% at 0.7 T. The results show that the data satisfy R=P1+P2T2+P3T4.5 for T
2007, 36(4):648-651.
Abstract:
Diamond film wafers were prepared by high power DC-plasma jet CVD method. The microstrures and the orientation of grain growth for the diamond film were studied by XRD, OM. SEM and Raman spectroscop. The results showed that grains grew in random orientation. Atom hydrogen etching benefited the nucleation and growth of crystal embryo. Methane concentration has important influence on the preferentially orientated growth of the grains. Upon a low methane concentration, (111) facet of the diamond film grew in preferential orientation, and an octahedron crystal was formed. Finally the optical diamond film with uniform center and edge, high quality was prepared. Adopting high power DC-plasma jet CVD method, the speed of growth of diamond was lower. Meantime, the vacancies and vacancy clusters were also found.
Diamond film wafers were prepared by high power DC-plasma jet CVD method. The microstrures and the orientation of grain growth for the diamond film were studied by XRD, OM. SEM and Raman spectroscop. The results showed that grains grew in random orientation. Atom hydrogen etching benefited the nucleation and growth of crystal embryo. Methane concentration has important influence on the preferentially orientated growth of the grains. Upon a low methane concentration, (111) facet of the diamond film grew in preferential orientation, and an octahedron crystal was formed. Finally the optical diamond film with uniform center and edge, high quality was prepared. Adopting high power DC-plasma jet CVD method, the speed of growth of diamond was lower. Meantime, the vacancies and vacancy clusters were also found.
2007, 36(4):652-655.
Abstract:
设计并采用自蔓延燃烧预热，水介质缓冲双向爆炸固结的方式制备了Mo／Cu功能梯度材料（FGM），观测了Mo／Cu FGM的显微组织并分析了固结过程。对各层的密度、硬度、电导率等进行了测量和分析。发现随着Cu含量的增多，材料的密度平缓递减但相对密度逐渐增大，硬度降低，电导率升高。相对密度从Mo层的94．2％到Cu层的98．4％，试样整体的相对密度达95．5％。Mo／CuFGM第1层与第2层间的剪切强度为214．8MPa；Mo／CuFGM第3层，第4层的热导率分别为204．76W·m^-1·K^-1和249．71W·m^-1·K^-1。
设计并采用自蔓延燃烧预热，水介质缓冲双向爆炸固结的方式制备了Mo／Cu功能梯度材料（FGM），观测了Mo／Cu FGM的显微组织并分析了固结过程。对各层的密度、硬度、电导率等进行了测量和分析。发现随着Cu含量的增多，材料的密度平缓递减但相对密度逐渐增大，硬度降低，电导率升高。相对密度从Mo层的94．2％到Cu层的98．4％，试样整体的相对密度达95．5％。Mo／CuFGM第1层与第2层间的剪切强度为214．8MPa；Mo／CuFGM第3层，第4层的热导率分别为204．76W·m^-1·K^-1和249．71W·m^-1·K^-1。
2007, 36(4):656-659.
Abstract:
7A60 alloys were prepared by spray deposition and casting techniques. The microstructures of the spray deposited and cast 7A60 alloys were studied using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The results indicate that the cast 7A60 alloy exhibits coarse grains and macrosegregation. The microstructure of the spray-deposited Al-Zn-Mg-Cu alloy is composed of the refined, equiaxial grains without obvious segration. Compared with the traditional technique, the spray deposition technique increased cooling rate greatly, refine the microstructure of 7A60 alloy obviously.
7A60 alloys were prepared by spray deposition and casting techniques. The microstructures of the spray deposited and cast 7A60 alloys were studied using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The results indicate that the cast 7A60 alloy exhibits coarse grains and macrosegregation. The microstructure of the spray-deposited Al-Zn-Mg-Cu alloy is composed of the refined, equiaxial grains without obvious segration. Compared with the traditional technique, the spray deposition technique increased cooling rate greatly, refine the microstructure of 7A60 alloy obviously.
2007, 36(4):665-670.
Abstract:
研究了微量Sc，Zr对Al-Zn-Mg-Cu合金组织性能的影响。结果表明：单独添加0．18％Zr，合金抗拉强度和延伸率明显低于单独添加0．18％Sc，但再结晶抑制效果优于单独添加0．18％Sc。复合添加Sc，Zr较单独添加Sc或Zr具有更好的晶粒细化作用，较强的固溶强化作用和再结晶抑制效果。在Zr含量一定的条件下，合金强度和延伸率随Sc添加量增加而提高。强度和延伸率增加与所析出的LI2结构的Al3Sc，Al3（Sc，Zr）粒子钉扎位错和亚结构，析出粒子数量增加、弥散度增大、分布均匀性提高、析出的η＇相所占的体积分数增加有关。当Sc，Zr复合添加量达到0．50％Sc＋0．18％Zr时，合金经固溶处理后发生部分再结晶，抗拉强度和延伸率大大降低。合金强度和延伸率降低与晶内、晶界大量析出粗大难熔的DO23结构的Al3（Sc，Zr）粒子有关。
研究了微量Sc，Zr对Al-Zn-Mg-Cu合金组织性能的影响。结果表明：单独添加0．18％Zr，合金抗拉强度和延伸率明显低于单独添加0．18％Sc，但再结晶抑制效果优于单独添加0．18％Sc。复合添加Sc，Zr较单独添加Sc或Zr具有更好的晶粒细化作用，较强的固溶强化作用和再结晶抑制效果。在Zr含量一定的条件下，合金强度和延伸率随Sc添加量增加而提高。强度和延伸率增加与所析出的LI2结构的Al3Sc，Al3（Sc，Zr）粒子钉扎位错和亚结构，析出粒子数量增加、弥散度增大、分布均匀性提高、析出的η＇相所占的体积分数增加有关。当Sc，Zr复合添加量达到0．50％Sc＋0．18％Zr时，合金经固溶处理后发生部分再结晶，抗拉强度和延伸率大大降低。合金强度和延伸率降低与晶内、晶界大量析出粗大难熔的DO23结构的Al3（Sc，Zr）粒子有关。
2007, 36(4):671-675.
Abstract:
设计了Mg-Al-Cu系的3种新合金AC33，AC53和AC63。发现3种实验合金的相组成相同：δ-Mg基体＋（δ-Mg＋Mg2Al2Cu3）共晶＋（δ-Mg＋Mg17Al2＋Mg2Al2Cu3）三元共晶。实验合金的室温力学性能优良。3种实验合金在200℃，50MPa条件下的蠕变抗力明显优于AZ91C合金，其中AC53合金的抗高温蠕变性能最优。Cu从以下途径影响了Mg-xAl合金的蠕变特性：Cu的添加抑制了Mg17Al12相的析出，使合金耐热性提高。该系列实验合金单从力学性能和抗蠕变性能来看，是非常有发展潜力的。
设计了Mg-Al-Cu系的3种新合金AC33，AC53和AC63。发现3种实验合金的相组成相同：δ-Mg基体＋（δ-Mg＋Mg2Al2Cu3）共晶＋（δ-Mg＋Mg17Al2＋Mg2Al2Cu3）三元共晶。实验合金的室温力学性能优良。3种实验合金在200℃，50MPa条件下的蠕变抗力明显优于AZ91C合金，其中AC53合金的抗高温蠕变性能最优。Cu从以下途径影响了Mg-xAl合金的蠕变特性：Cu的添加抑制了Mg17Al12相的析出，使合金耐热性提高。该系列实验合金单从力学性能和抗蠕变性能来看，是非常有发展潜力的。
2007, 36(4):676-679.
Abstract:
采用快速冷冻沉淀法制备了非晶态纳米氢氧化镍粉体材料。讨论了反应体系的pH值、温度和表面活性剂等因素对粉体特性的影响。结果表明，当选择表面活性剂为Tween80，反应体系的pH=11-12，T=55℃，反应时间为1h时，所制备的非晶氢氧化镍粉体粒度为30nm左右，形貌近似球形。将样品粉体作为MH-Ni电池正极活性材料，其充电电压低，电化学极化阻抗小，放电平台高（1．258V），且平稳时间较长，放电比容量达349．85mAh／g。
采用快速冷冻沉淀法制备了非晶态纳米氢氧化镍粉体材料。讨论了反应体系的pH值、温度和表面活性剂等因素对粉体特性的影响。结果表明，当选择表面活性剂为Tween80，反应体系的pH=11-12，T=55℃，反应时间为1h时，所制备的非晶氢氧化镍粉体粒度为30nm左右，形貌近似球形。将样品粉体作为MH-Ni电池正极活性材料，其充电电压低，电化学极化阻抗小，放电平台高（1．258V），且平稳时间较长，放电比容量达349．85mAh／g。
2007, 36(4):680-684.
Abstract:
IrTa-X mixed metal oxide (MMO) coating titanium anode was prepared by thermal decomposition process. The electrochemical performance of Ti anode was investigated by means of polarization curves. The surface morphology of the coating was observed by SEM. The relationship between the anode lifetime and coating thickness and the anode current density was studied. The results indicate that the Ti anode has the superior electrochemical performance and the longer lifetime. So the MMO anode will be the promissing auxiliary anode of impressed current cathodic protection for reinforced concrete structure.
IrTa-X mixed metal oxide (MMO) coating titanium anode was prepared by thermal decomposition process. The electrochemical performance of Ti anode was investigated by means of polarization curves. The surface morphology of the coating was observed by SEM. The relationship between the anode lifetime and coating thickness and the anode current density was studied. The results indicate that the Ti anode has the superior electrochemical performance and the longer lifetime. So the MMO anode will be the promissing auxiliary anode of impressed current cathodic protection for reinforced concrete structure.
2007, 36(4):685-689.
Abstract:
In order to improve the wear resistance of titanium alloys, a process of oxygen-permeation & diffusion-solution (OP-DS) was developed, by which no oxide film was formed on the surface. The titanium alloy of TC11 was studied by TGA, SEM, XRD, XPS and micro-hardness tester at high temperature. The results indicate that the hardening depth and the hardness of surface layer can be remarkably enhanced, and the surface oxide film is decreased by the OP-DS process. The pre-OP treating time exhibited significant effect on the following DS treatment, even a hardened layer without oxide scale could be produced by proper combination of OP and DS. The OP-DS process was also discussed in terms of thermal diffusion mechanism.
In order to improve the wear resistance of titanium alloys, a process of oxygen-permeation & diffusion-solution (OP-DS) was developed, by which no oxide film was formed on the surface. The titanium alloy of TC11 was studied by TGA, SEM, XRD, XPS and micro-hardness tester at high temperature. The results indicate that the hardening depth and the hardness of surface layer can be remarkably enhanced, and the surface oxide film is decreased by the OP-DS process. The pre-OP treating time exhibited significant effect on the following DS treatment, even a hardened layer without oxide scale could be produced by proper combination of OP and DS. The OP-DS process was also discussed in terms of thermal diffusion mechanism.
2007, 36(4):695-699.
Abstract:
采用机械合金化法和真空熔炼法制备了不同显微组织的Ni-20Cr（质量分数，％，下同）合金，并研究其在950℃，75％Na2SO4＋25％K2SO4（质量分数，下同）盐膜下的热腐蚀行为。结果表明：细晶的机械合金化Ni-20Cr合金热腐蚀后表面形成了单一连续的Cr2O3外氧化膜，有效地阻止了硫的向内扩散，延长了热腐蚀过程的孕育期，呈现出较普通晶粒尺寸的熔炼Ni-20Cr合金更好的抗热腐蚀性能。
采用机械合金化法和真空熔炼法制备了不同显微组织的Ni-20Cr（质量分数，％，下同）合金，并研究其在950℃，75％Na2SO4＋25％K2SO4（质量分数，下同）盐膜下的热腐蚀行为。结果表明：细晶的机械合金化Ni-20Cr合金热腐蚀后表面形成了单一连续的Cr2O3外氧化膜，有效地阻止了硫的向内扩散，延长了热腐蚀过程的孕育期，呈现出较普通晶粒尺寸的熔炼Ni-20Cr合金更好的抗热腐蚀性能。
2007, 36(4):700-704.
Abstract:
Structure and forming process of the Ti/Al diffusion bonding joints were studied by means of scanning electron microscopy (SEM), X-ray diffractometry (XRD) and shear strength measurement. The TA2 and L4 were used as bonding couples. The results showed that the forming process of joints included four stages. The primary and unique phase was TiAl3 from the diffusion reaction for long time. There was a delay time tD before TiAl3 appeared, mainly affected by temperature. The joint strength depended on the metallurgical combination percentage and interface structure of diffusion zone, reaching or even exceeding the strength of L4 when the TiAl3 formed like sheet and layer. The shearing fracture of joints occurred on the interface of Al and diffusion zone or in the Al-based metal.
Structure and forming process of the Ti/Al diffusion bonding joints were studied by means of scanning electron microscopy (SEM), X-ray diffractometry (XRD) and shear strength measurement. The TA2 and L4 were used as bonding couples. The results showed that the forming process of joints included four stages. The primary and unique phase was TiAl3 from the diffusion reaction for long time. There was a delay time tD before TiAl3 appeared, mainly affected by temperature. The joint strength depended on the metallurgical combination percentage and interface structure of diffusion zone, reaching or even exceeding the strength of L4 when the TiAl3 formed like sheet and layer. The shearing fracture of joints occurred on the interface of Al and diffusion zone or in the Al-based metal.
2007, 36(4):705-708.
Abstract:
In order to improve the inner quality of superalloy master ingots, a technology of vacuum electromagnetic casting (V-EMC) was developed for the superalloy, i.e., applying electromagnetic stirring to the solidification process of vacuum casting. The effect of electromagnetic stirring on the inner quality of superalloy master ingots was studied with EPMA and optical microscope. The results show that the equiaxial crystals of superalloy master ingot can be effectively refined and increased, and the central shrinkage porosity and the dendritic segregation are greatly reduced, so the inner quality is obviously improved for the superalloy master ingots when electromagnetic stirring at a frequency of 50 Hz and a current of 60 A.
In order to improve the inner quality of superalloy master ingots, a technology of vacuum electromagnetic casting (V-EMC) was developed for the superalloy, i.e., applying electromagnetic stirring to the solidification process of vacuum casting. The effect of electromagnetic stirring on the inner quality of superalloy master ingots was studied with EPMA and optical microscope. The results show that the equiaxial crystals of superalloy master ingot can be effectively refined and increased, and the central shrinkage porosity and the dendritic segregation are greatly reduced, so the inner quality is obviously improved for the superalloy master ingots when electromagnetic stirring at a frequency of 50 Hz and a current of 60 A.
2007, 36(4):709-712.
Abstract:
在较高浓度的硝酸银溶液中，采用水合肼为还原剂，PVP为保护剂的化学还原法制备了纳米银粉。通过对还原剂、保护剂用量和硝酸银浓度、温度、还原剂的加入方式、pH值等因素对纳米银粉粒度和形貌影响的考察，获得了制备纳米银粉的工艺。在AgNO3浓度为0．6mol／L，PVP／Ag摩尔比为1．5，水合肼浓度为0．6mol／L，pH值为5～6，温度为60℃的条件下，制备出了粒度均匀且粒度在50nm左右的纳米银粉。
在较高浓度的硝酸银溶液中，采用水合肼为还原剂，PVP为保护剂的化学还原法制备了纳米银粉。通过对还原剂、保护剂用量和硝酸银浓度、温度、还原剂的加入方式、pH值等因素对纳米银粉粒度和形貌影响的考察，获得了制备纳米银粉的工艺。在AgNO3浓度为0．6mol／L，PVP／Ag摩尔比为1．5，水合肼浓度为0．6mol／L，pH值为5～6，温度为60℃的条件下，制备出了粒度均匀且粒度在50nm左右的纳米银粉。
2007, 36(4):713-716.
Abstract:
在含氟离子的水溶液中，采用Al粉直接置换还原Ni盐的方法，实现了纳米Ni在Al粉表面上的快速化学沉积，制备出核-壳结构的Ni／Al复合粉末。探讨了反应的过程，利用粒度分析，SEM，XRD，BET，XPS等测试手段对复合粉末进行了微观测试和表征。结果表明：平均粒度为7．13μm的铝颗粒表面包覆着一层纳米Ni（其晶粒度为20．4nm），形成了壳层。
在含氟离子的水溶液中，采用Al粉直接置换还原Ni盐的方法，实现了纳米Ni在Al粉表面上的快速化学沉积，制备出核-壳结构的Ni／Al复合粉末。探讨了反应的过程，利用粒度分析，SEM，XRD，BET，XPS等测试手段对复合粉末进行了微观测试和表征。结果表明：平均粒度为7．13μm的铝颗粒表面包覆着一层纳米Ni（其晶粒度为20．4nm），形成了壳层。
2007, 36(4):721-723.
Abstract:
Based on the main experiment parameters of DyFe2 alloy preparation by reduction-diffusion process: reaction temperature, holding time, added quantity of Ca and particle size of Fe, the BP neural network was established and used to predicate the transformation efficiency of DyFe2 alloy. The neural network was simulated by 44 groups of experimental data and was tested. It has been proved that the neural network has good performance to predict the transformation efficiency of DyFe2 alloy. This design of neural network is able to shorten the time of experiment, reduce the experiment cost, and optimize the preparation processes.
Based on the main experiment parameters of DyFe2 alloy preparation by reduction-diffusion process: reaction temperature, holding time, added quantity of Ca and particle size of Fe, the BP neural network was established and used to predicate the transformation efficiency of DyFe2 alloy. The neural network was simulated by 44 groups of experimental data and was tested. It has been proved that the neural network has good performance to predict the transformation efficiency of DyFe2 alloy. This design of neural network is able to shorten the time of experiment, reduce the experiment cost, and optimize the preparation processes.
2007, 36(4):724-727.
Abstract:
On the basis of Zeta value measurement of the silver nanopowders prepared by DC arc plasma evaporation, the influences of supersonic dispersing time and surfactant concentration on the dispersing properties in alcohol solvent were studied systematically for the silver nanopowders by using polyvinylpirrolidone (PVP), cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and oleic acid as surfactants. The results show that the suspension dispersion effects increased up to a maximum, then decreased with the increasing of ultrasonic dispersing time, similar to the increase of surfactant concentration. PVP is the best dispersant for the four kinds of surfactant using in the experiments, the optimum dispersing condition is PVP of 1.5wt% for the ultrasonic dispersing time of 40 min.
On the basis of Zeta value measurement of the silver nanopowders prepared by DC arc plasma evaporation, the influences of supersonic dispersing time and surfactant concentration on the dispersing properties in alcohol solvent were studied systematically for the silver nanopowders by using polyvinylpirrolidone (PVP), cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and oleic acid as surfactants. The results show that the suspension dispersion effects increased up to a maximum, then decreased with the increasing of ultrasonic dispersing time, similar to the increase of surfactant concentration. PVP is the best dispersant for the four kinds of surfactant using in the experiments, the optimum dispersing condition is PVP of 1.5wt% for the ultrasonic dispersing time of 40 min.
2007, 36(4):728-731.
Abstract:
以硫酸亚铁、硫酸镍、碳酸钠和石墨微球为主要原料，利用非均相成核工艺制备出水合氧化铁和碱式碳酸镍均匀包覆石墨的前驱体微球：通过对前驱体进行热还原处理得到了晶粒约为50nm的γ-FeNi合金颗粒层包覆石墨的产物微球。利用SEM，EDS，XRD对前驱体和产物的形貌、成分、物相分别进行了表征，并利用TG／DSC对前驱体热分解过程进行了分析。通过研究，得出了制备这种核．壳结构复合微球的优化工艺参数。
以硫酸亚铁、硫酸镍、碳酸钠和石墨微球为主要原料，利用非均相成核工艺制备出水合氧化铁和碱式碳酸镍均匀包覆石墨的前驱体微球：通过对前驱体进行热还原处理得到了晶粒约为50nm的γ-FeNi合金颗粒层包覆石墨的产物微球。利用SEM，EDS，XRD对前驱体和产物的形貌、成分、物相分别进行了表征，并利用TG／DSC对前驱体热分解过程进行了分析。通过研究，得出了制备这种核．壳结构复合微球的优化工艺参数。
2007, 36(4):732-735.
Abstract:
采用经高能球磨的超细93W-4.9Ni-2.1Fe预合金粉末，并添加少量的Re，经压制，烧结制取试样。研究Re对93W-4.9Ni-2.1Fe合金性能和微观组织的影响。用机械式拉力试验机测量试样拉伸强度，用扫描电镜观察试样拉伸断1：3的形貌，用金相显微镜对试样显微组织进行测试分析。结果表明：当添加0％-0．8％Re（质量分数，下同）时，随着Re添加量的增加，合金的相对密度稳定在99．43％～99．49％，烧结样品延伸率从不加Re时的26．47％降至0．8％Re时的14．71％，合金的抗拉强度由不加Re时的1025MPa增加到0．8％Re时的1142MPa，合金拉伸断口收缩率由不加Re时的20．45％降至0．8％Re时的10．91％；随着Re含量的增加，合金中W晶粒的穿晶解理断裂的比例增加，而粘结相延性断裂的比例减少；随着Re含量的增加，合金中W晶粒尺寸明显减小，由不加Re时的40μm-45μm减小到添加0．8％Re时的20μm-25μm。
采用经高能球磨的超细93W-4.9Ni-2.1Fe预合金粉末，并添加少量的Re，经压制，烧结制取试样。研究Re对93W-4.9Ni-2.1Fe合金性能和微观组织的影响。用机械式拉力试验机测量试样拉伸强度，用扫描电镜观察试样拉伸断1：3的形貌，用金相显微镜对试样显微组织进行测试分析。结果表明：当添加0％-0．8％Re（质量分数，下同）时，随着Re添加量的增加，合金的相对密度稳定在99．43％～99．49％，烧结样品延伸率从不加Re时的26．47％降至0．8％Re时的14．71％，合金的抗拉强度由不加Re时的1025MPa增加到0．8％Re时的1142MPa，合金拉伸断口收缩率由不加Re时的20．45％降至0．8％Re时的10．91％；随着Re含量的增加，合金中W晶粒的穿晶解理断裂的比例增加，而粘结相延性断裂的比例减少；随着Re含量的增加，合金中W晶粒尺寸明显减小，由不加Re时的40μm-45μm减小到添加0．8％Re时的20μm-25μm。
2007, 36(4):736-739.
Abstract:
Rare-earth Mg-based hydrogen storage electrode alloys of LaMg2Ni9-xCox(x=0.3~6.0) and MlMg2Ni9-xCox(x=0.3~4.5) with different stoichiometric ratios were prepared by coprecipitation-reduction-diffusion method. Electrochemical analyses showed that the alloys prepared by this method can be easily activated; with x increasing, no obvious change for the activity numbers, and the discharge capacity decreased and the cyclic stability of alloy electrodes was effectively improved. Their activity numbers were larger than La-alloys, the discharge capacity decreased and the cyclic stability of mix-alloys was better than La-alloys. Structure analyses showed that the main phases of alloys were MgNi2 and LaNi5, the amount of LaCo5 phase and LaCo3 phase increased with Co content increasing.
Rare-earth Mg-based hydrogen storage electrode alloys of LaMg2Ni9-xCox(x=0.3~6.0) and MlMg2Ni9-xCox(x=0.3~4.5) with different stoichiometric ratios were prepared by coprecipitation-reduction-diffusion method. Electrochemical analyses showed that the alloys prepared by this method can be easily activated; with x increasing, no obvious change for the activity numbers, and the discharge capacity decreased and the cyclic stability of alloy electrodes was effectively improved. Their activity numbers were larger than La-alloys, the discharge capacity decreased and the cyclic stability of mix-alloys was better than La-alloys. Structure analyses showed that the main phases of alloys were MgNi2 and LaNi5, the amount of LaCo5 phase and LaCo3 phase increased with Co content increasing.
2007, 36(4):740-743.
Abstract:
将Ag粉和Al2O3粉按不同配比（体积分数，下同）配制后进行高能球磨，然后烧结。研究不同Ag含量对试样烧结性能与断裂韧性的影响。结果表明，高能球磨可使颗粒细化。由于粒子尺寸细小，具有较高的表面能，使得试样的烧结温度明显降低。并且第二相Ag粒子的添加也可明显降低试样的烧结温度，但同时也不同程度地降低了试样的相对密度。Ag粒子的添加量对试样的断裂韧性有较大影响。当Ag含量从0％增加到5％时，断裂韧性也随之增大，当Ag含量为5％时，试样的断裂韧性达到最大值5．12MPa·m^0.5。当Ag含量从5％增加到10％时，由于相对密度急剧降低，使得试样的断裂韧性也随之明显降低。
将Ag粉和Al2O3粉按不同配比（体积分数，下同）配制后进行高能球磨，然后烧结。研究不同Ag含量对试样烧结性能与断裂韧性的影响。结果表明，高能球磨可使颗粒细化。由于粒子尺寸细小，具有较高的表面能，使得试样的烧结温度明显降低。并且第二相Ag粒子的添加也可明显降低试样的烧结温度，但同时也不同程度地降低了试样的相对密度。Ag粒子的添加量对试样的断裂韧性有较大影响。当Ag含量从0％增加到5％时，断裂韧性也随之增大，当Ag含量为5％时，试样的断裂韧性达到最大值5．12MPa·m^0.5。当Ag含量从5％增加到10％时，由于相对密度急剧降低，使得试样的断裂韧性也随之明显降低。
2007, 36(4):744-746.
Abstract:
采用高能喷丸技术在铝合金表面制备出纳米晶结构层，利用金相显微镜（OM），扫描电子显微镜（SEM／EDS），透射电子显微镜（TEM）及X射线衍射仪（XRD）等设备对高能喷丸铝合金表面层的显微结构及成分进行分析。结果表明：在高能喷丸表面纳米化过程中，弹丸中的Fe，cr原子在强制机械力的作用下转移进入铝合金表面，在材料表层约30μm的深度范围内形成分布不均匀的合金化层。这可能是纳米晶体中大量界面的形成使合金元素原子能够快速扩散和偏聚的结果。
采用高能喷丸技术在铝合金表面制备出纳米晶结构层，利用金相显微镜（OM），扫描电子显微镜（SEM／EDS），透射电子显微镜（TEM）及X射线衍射仪（XRD）等设备对高能喷丸铝合金表面层的显微结构及成分进行分析。结果表明：在高能喷丸表面纳米化过程中，弹丸中的Fe，cr原子在强制机械力的作用下转移进入铝合金表面，在材料表层约30μm的深度范围内形成分布不均匀的合金化层。这可能是纳米晶体中大量界面的形成使合金元素原子能够快速扩散和偏聚的结果。
2007, 36(4):747-749.
Abstract:
The permanent bulk magnets of Nd10.5Dy0.5Fe76.9Nb1Co5B6.1 were prepared by the process of field-activated sintering in this paper. The microstructure was discussed by XRD, SEM and so on. The results show that the optimal magnetic properties of Nd10.5Dy0.5Fe76.9Nb1Co5B6.1 (Br=0.6498 T, Hcj=714 kA/m, (BH)max=63 kJ/m3) magnets have been obtained while treated at 823 K for 300 s by field-activated sintering. The compressive strength increases as the increase of sintering temperature.
The permanent bulk magnets of Nd10.5Dy0.5Fe76.9Nb1Co5B6.1 were prepared by the process of field-activated sintering in this paper. The microstructure was discussed by XRD, SEM and so on. The results show that the optimal magnetic properties of Nd10.5Dy0.5Fe76.9Nb1Co5B6.1 (Br=0.6498 T, Hcj=714 kA/m, (BH)max=63 kJ/m3) magnets have been obtained while treated at 823 K for 300 s by field-activated sintering. The compressive strength increases as the increase of sintering temperature.
2007, 36(4):750-752.
Abstract:
采用一种以Sn作为添加剂的低温瞬时液相烧结方法来制备Terfenol-D。分别研究了粉末粒度、Sn含量、成型压力、烧结工艺对样品磁性能（包括磁致伸缩性能）和力学性能的影响。获得了在12×79．6kA／m磁场下，与磁场平行方向磁致伸缩值为5．46×10^-4。的烧结样品，其制备条件为：粉末粒度〈75μm，Sn含量为8％（质量分数，下同），成型压力为1．0GPa，在250℃持续烧结150s。
采用一种以Sn作为添加剂的低温瞬时液相烧结方法来制备Terfenol-D。分别研究了粉末粒度、Sn含量、成型压力、烧结工艺对样品磁性能（包括磁致伸缩性能）和力学性能的影响。获得了在12×79．6kA／m磁场下，与磁场平行方向磁致伸缩值为5．46×10^-4。的烧结样品，其制备条件为：粉末粒度〈75μm，Sn含量为8％（质量分数，下同），成型压力为1．0GPa，在250℃持续烧结150s。
