Volume 34,Issue 10,2005 Table of Contents
2005, 34(10):1513-1516.
Abstract:
对厚约3pm的金属钼薄膜进行低温离子渗硫处理，得到了单质金属钼与固体润滑剂二硫化钼（MoS2）共存的复合固体润滑渗硫层。利用SEM和EDX分析了复合渗硫层表面、截面及磨损面的形貌及成分分布，用XPS分析了复合渗硫层表面化合价态，用纳米压痕仪测定了复合渗硫层的硬度及弹性模量。摩擦磨损实验表明，该渗硫层是一种非常理想的摩擦表面，具有优异的减摩耐磨抗擦伤性能。离子渗硫技术为原位合成固体润滑剂MoS2提供了一种新方法。
对厚约3pm的金属钼薄膜进行低温离子渗硫处理，得到了单质金属钼与固体润滑剂二硫化钼（MoS2）共存的复合固体润滑渗硫层。利用SEM和EDX分析了复合渗硫层表面、截面及磨损面的形貌及成分分布，用XPS分析了复合渗硫层表面化合价态，用纳米压痕仪测定了复合渗硫层的硬度及弹性模量。摩擦磨损实验表明，该渗硫层是一种非常理想的摩擦表面，具有优异的减摩耐磨抗擦伤性能。离子渗硫技术为原位合成固体润滑剂MoS2提供了一种新方法。
2 Effect of Cr and CrTi Underlayers on Magnetic and Structural Performances of CoCrPt Thin Film Media
2005, 34(10):1517-1519.
Abstract:
为了改善记录介质的磁性能,研究了溅射Cr和CrTi底层对Co68Cr17Pt15性能的影响。发现在玻璃盘基和CoCrPt磁性层之间引入100nm厚的Cr底层,可使介质矫顽力从56kA·m-1增加到127kA·m-1,同时剩磁比和矫顽力矩形比分别增加66%和74%。同时还发现Cr底层厚度对介质磁性能有较大影响。考虑到减小Cr底层和磁性层的晶格匹配,在Cr底层里添加Ti元素,当Ti原子分数达到1.5%时,即使在室温下溅射,薄膜也有好的面内磁滞回线,此时矫顽力可达到160kA·m-1。X射线衍射表明在介质中引入Cr和CrTi底层,由于薄膜能更好的沿着垂直于易磁化轴方向生长而使介质性能提高。
为了改善记录介质的磁性能,研究了溅射Cr和CrTi底层对Co68Cr17Pt15性能的影响。发现在玻璃盘基和CoCrPt磁性层之间引入100nm厚的Cr底层,可使介质矫顽力从56kA·m-1增加到127kA·m-1,同时剩磁比和矫顽力矩形比分别增加66%和74%。同时还发现Cr底层厚度对介质磁性能有较大影响。考虑到减小Cr底层和磁性层的晶格匹配,在Cr底层里添加Ti元素,当Ti原子分数达到1.5%时,即使在室温下溅射,薄膜也有好的面内磁滞回线,此时矫顽力可达到160kA·m-1。X射线衍射表明在介质中引入Cr和CrTi底层,由于薄膜能更好的沿着垂直于易磁化轴方向生长而使介质性能提高。
2005, 34(10):1520-1523.
Abstract:
The classical optical theory was introduced to calculate the interaction between laser beam and powder stream, on the basis of which the effect of powder feeding rate on the laser intensity and temperature of the particles at different sites on the surface of the workpiece was investigated. It is shown that the peak values of both laser intensity and particle temperature decrease with increasing the powder feeding rate. And simultaneously, the laser intensity distribution and the temperature of the particles at different sites on the surface of the workpiece tend to be even. It is suggested that such results should be considered in model of laser cladding due to their subtle effects on the dynamic processes in laser molten pool.
The classical optical theory was introduced to calculate the interaction between laser beam and powder stream, on the basis of which the effect of powder feeding rate on the laser intensity and temperature of the particles at different sites on the surface of the workpiece was investigated. It is shown that the peak values of both laser intensity and particle temperature decrease with increasing the powder feeding rate. And simultaneously, the laser intensity distribution and the temperature of the particles at different sites on the surface of the workpiece tend to be even. It is suggested that such results should be considered in model of laser cladding due to their subtle effects on the dynamic processes in laser molten pool.
2005, 34(10):1524-1527.
Abstract:
As electric field is applied, the behaviors of micro / nano-electromechanical systems become complicated due to the unavoidable mutual actions of Casimir force, residual stresses and electrostatic force in the system. Analytical expressions of the deflection of a bridge shaped device under the mutual actions of these forces in the systems are derived. It is shown that the rather great tensile residual stress enhances wavy behavior of the deflection.
As electric field is applied, the behaviors of micro / nano-electromechanical systems become complicated due to the unavoidable mutual actions of Casimir force, residual stresses and electrostatic force in the system. Analytical expressions of the deflection of a bridge shaped device under the mutual actions of these forces in the systems are derived. It is shown that the rather great tensile residual stress enhances wavy behavior of the deflection.
2005, 34(10):1528-1531.
Abstract:
以商业纯Gd为原料,采用非自耗电弧炉氩气保护下熔炼了Gd5Si2Ge2-xSnx(x=0.2,0.5,1)和Gd5Si2-yGe2Sny(y=0.1,0.2,0.5)系列合金,研究Sn合金化对Gd5Si2Ge2晶体结构和磁热性能的影响.粉末XRD结果表明Sn代Ge样品具有正交Gd5Si4型结构;Sn少量代Si(y=0.1,0.2)的样品具有单斜Gd5Si2Ge2型结构;Gd5Si1.5Ge2Sn0.5则为单斜和正交的混合结构.用超导量子磁强计(SQUID)测定了样品的M-T和不同温度的M-H曲线,结果表明Gd5Si2Ge2-xSnx(x=0.2,0.5,1)不具有巨磁热效应;Gd5Si1 9Ge2Sn01合金的最大磁熵变达15.3 J/kg·K(0 T～5 T),具有巨磁热效应.
以商业纯Gd为原料,采用非自耗电弧炉氩气保护下熔炼了Gd5Si2Ge2-xSnx(x=0.2,0.5,1)和Gd5Si2-yGe2Sny(y=0.1,0.2,0.5)系列合金,研究Sn合金化对Gd5Si2Ge2晶体结构和磁热性能的影响.粉末XRD结果表明Sn代Ge样品具有正交Gd5Si4型结构;Sn少量代Si(y=0.1,0.2)的样品具有单斜Gd5Si2Ge2型结构;Gd5Si1.5Ge2Sn0.5则为单斜和正交的混合结构.用超导量子磁强计(SQUID)测定了样品的M-T和不同温度的M-H曲线,结果表明Gd5Si2Ge2-xSnx(x=0.2,0.5,1)不具有巨磁热效应;Gd5Si1 9Ge2Sn01合金的最大磁熵变达15.3 J/kg·K(0 T～5 T),具有巨磁热效应.
2005, 34(10):1532-1536.
Abstract:
By means of growth unit of anion coordination polyhedron theory, growth units and equilibrium morphology of TiC Crystal which grew freely in titanium alloy were investigated. On the basis of the research on the characteristics of TiC crystal structure, energy level fission of orbit and bonding orbit of Ti crystal, through verifying the bonding energy released when TiC crystal formed different growth units, it can be concluded that the growth unit of TiC crystal which freely grew in molten titanium is TIC6. According to the stacking mode of the TiC6 crystal growth unit, the equilibrium morphology of TiC crystal is octahedron. However during the actual sample preparation, because of the undercooling and inhomogeneity of the solute distribution, TiC crystal may have different morphologies. Those conclusions are proved by the results of unidirectional solidification experiments in floating zone
By means of growth unit of anion coordination polyhedron theory, growth units and equilibrium morphology of TiC Crystal which grew freely in titanium alloy were investigated. On the basis of the research on the characteristics of TiC crystal structure, energy level fission of orbit and bonding orbit of Ti crystal, through verifying the bonding energy released when TiC crystal formed different growth units, it can be concluded that the growth unit of TiC crystal which freely grew in molten titanium is TIC6. According to the stacking mode of the TiC6 crystal growth unit, the equilibrium morphology of TiC crystal is octahedron. However during the actual sample preparation, because of the undercooling and inhomogeneity of the solute distribution, TiC crystal may have different morphologies. Those conclusions are proved by the results of unidirectional solidification experiments in floating zone
2005, 34(10):1537-1540.
Abstract:
在氩气气氛中用熔炼法制备了Pr2Fe17-xCox系列合金，通过粉末X射线衍射和SQUID磁强计研究了样品的结构、磁性和磁熵变。结果表明：Pr2Fe17-xCox系列合金具有菱方Th2Zn17型结构；通过成分微调使其居里温度处在室温附近：Pr2Fe17-xCox，系列合金有较大的磁熵变，在低场下的磁熵变是金属Gd的65％～73％，而高场下的磁熵变则为金属Gd的63％～68％；但其成本约为金属Gd的1／10，具有很高的性价比，是一类有很大应用潜力的室温磁致冷材料。
在氩气气氛中用熔炼法制备了Pr2Fe17-xCox系列合金，通过粉末X射线衍射和SQUID磁强计研究了样品的结构、磁性和磁熵变。结果表明：Pr2Fe17-xCox系列合金具有菱方Th2Zn17型结构；通过成分微调使其居里温度处在室温附近：Pr2Fe17-xCox，系列合金有较大的磁熵变，在低场下的磁熵变是金属Gd的65％～73％，而高场下的磁熵变则为金属Gd的63％～68％；但其成本约为金属Gd的1／10，具有很高的性价比，是一类有很大应用潜力的室温磁致冷材料。
2005, 34(10):1541-1545.
Abstract:
The calculations of total energy, band structure, electronic density of states and Mulliken population of LaNi5 have been performed by adopting the method of total energy based on the Density Functional Theory. The augmented plane wave function was selected as the basis set in combination with Ultra-soft Pseudopotential technology. The electronic structures of LaNi5 and LaNisH and the change in the formation of LaNisH were analyzed according to the result of total density of states and partial density of states for different orbits. The metal-hydrogen bonding feature was discussed. The stability of the hydrogen interstitial site and the preferred site occupation of the absorbed hydrogen atoms were preliminarily explored.
The calculations of total energy, band structure, electronic density of states and Mulliken population of LaNi5 have been performed by adopting the method of total energy based on the Density Functional Theory. The augmented plane wave function was selected as the basis set in combination with Ultra-soft Pseudopotential technology. The electronic structures of LaNi5 and LaNisH and the change in the formation of LaNisH were analyzed according to the result of total density of states and partial density of states for different orbits. The metal-hydrogen bonding feature was discussed. The stability of the hydrogen interstitial site and the preferred site occupation of the absorbed hydrogen atoms were preliminarily explored.
2005, 34(10):1546-1549.
Abstract:
The fracture morphology and microstructure of Uranium-Niobium caused by explosive loading were investigated. The results show that U-Nb is in shear fracture with explosive loading, there are many adiabatic shear bands(ABS) in microstrcture caused by high strain rate. The grains near the ASB have been elongated obviously. The microcracks exist in fragments and spread along the ASB. The fragments form when the cracks meet with the main cracks resulting from the tensile strain on the circumference direction of U-Nb tubes.
The fracture morphology and microstructure of Uranium-Niobium caused by explosive loading were investigated. The results show that U-Nb is in shear fracture with explosive loading, there are many adiabatic shear bands(ABS) in microstrcture caused by high strain rate. The grains near the ASB have been elongated obviously. The microcracks exist in fragments and spread along the ASB. The fragments form when the cracks meet with the main cracks resulting from the tensile strain on the circumference direction of U-Nb tubes.
2005, 34(10):1550-1553.
Abstract:
采用固相反应法制备了Li1＋xV3-yMyO8（M=Mo，P：O≤y≤0.4），研究了不同Mo和P含量对Li1＋xV3-yMyO8相的影响，并首次对其进行了高温阴极放电性能的研究。结果表明：Mo和P掺杂量分别为y≤0．2和y〈0．2时可获得纯Li1＋xV3-yMyO8相：Mo掺杂使Li1＋xV3-yMyO8峰值电压提高0-3V，比容量提高25％，嵌入的Li^＋量最高可达x=3．8：P掺杂（y≤0．20）Li1＋xV3-yMyO8的峰值电压和比容量影响较小。化学嵌锂实验也证实掺杂后的材料具有更快的Li^＋嵌入速度。
采用固相反应法制备了Li1＋xV3-yMyO8（M=Mo，P：O≤y≤0.4），研究了不同Mo和P含量对Li1＋xV3-yMyO8相的影响，并首次对其进行了高温阴极放电性能的研究。结果表明：Mo和P掺杂量分别为y≤0．2和y〈0．2时可获得纯Li1＋xV3-yMyO8相：Mo掺杂使Li1＋xV3-yMyO8峰值电压提高0-3V，比容量提高25％，嵌入的Li^＋量最高可达x=3．8：P掺杂（y≤0．20）Li1＋xV3-yMyO8的峰值电压和比容量影响较小。化学嵌锂实验也证实掺杂后的材料具有更快的Li^＋嵌入速度。
2005, 34(10):1554-1557.
Abstract:
Magnesium alloys were treated in a solution containing silicate, fluoride and glycerol at a constant applied current density. The effect of current density on breakdown voltage, ignition time and coating thickness was investigated. SEM was employed to examine the surface morphology of ceramic coatings formed on magnesium alloys at different applied current density, and the corrosion resistance was also measured by EIS. It was concluded that according to the Voltage-Time response, the MAO process is simply divided into gradually increasing stage and a relative stable stage. With the increase of applied current density the cell voltage increasing rate is improved, coating thickness is increased lineally and ignition time is decreased, but the breakdown voltage has no apparent variation. The number of pores is decreased with the increase of current density, but the diameters of the pores are increased; EIS results indicate that corrosion resistance of ceramic coating increase firstly, then decrease with the increase of applied current density.
Magnesium alloys were treated in a solution containing silicate, fluoride and glycerol at a constant applied current density. The effect of current density on breakdown voltage, ignition time and coating thickness was investigated. SEM was employed to examine the surface morphology of ceramic coatings formed on magnesium alloys at different applied current density, and the corrosion resistance was also measured by EIS. It was concluded that according to the Voltage-Time response, the MAO process is simply divided into gradually increasing stage and a relative stable stage. With the increase of applied current density the cell voltage increasing rate is improved, coating thickness is increased lineally and ignition time is decreased, but the breakdown voltage has no apparent variation. The number of pores is decreased with the increase of current density, but the diameters of the pores are increased; EIS results indicate that corrosion resistance of ceramic coating increase firstly, then decrease with the increase of applied current density.
2005, 34(10):1558-1561.
Abstract:
异质形核是凝固领域的核心问题之一，界面共格对应理论无法解释金液滴异质形核过程中ZrC，TiC，TiN等基底的触媒作用优于TiO的现象。利用余氏“固体与分子经验电子理论”以及程氏“改进的TFD模型中表面电子密度相等的边界条件”，分析表明界面共格对应并不是有效触媒基底的本质要求：在Tillen静电作用理论基础上，建立了Au液凝同异质形核价电予模型与基底触媒效用判据，据此分析了ZrC，TiC，TiN，TiO基底对Au液滴异质形核的触媒效用，与实验结果吻合。
异质形核是凝固领域的核心问题之一，界面共格对应理论无法解释金液滴异质形核过程中ZrC，TiC，TiN等基底的触媒作用优于TiO的现象。利用余氏“固体与分子经验电子理论”以及程氏“改进的TFD模型中表面电子密度相等的边界条件”，分析表明界面共格对应并不是有效触媒基底的本质要求：在Tillen静电作用理论基础上，建立了Au液凝同异质形核价电予模型与基底触媒效用判据，据此分析了ZrC，TiC，TiN，TiO基底对Au液滴异质形核的触媒效用，与实验结果吻合。
2005, 34(10):1562-1564.
Abstract:
建立了超导复合带材的细观力学假设和模型、以及成型过程的有限元分析模型。模拟了辊轧、平模冷压成型时复合带材的变形情况以及复合带材横向裂纹、芯丝断裂及边部破裂的产生。带材成型的有限元模拟对于超导复合带材的成型研究具有很好的指导作用。
建立了超导复合带材的细观力学假设和模型、以及成型过程的有限元分析模型。模拟了辊轧、平模冷压成型时复合带材的变形情况以及复合带材横向裂纹、芯丝断裂及边部破裂的产生。带材成型的有限元模拟对于超导复合带材的成型研究具有很好的指导作用。
2005, 34(10):1565-1568.
Abstract:
A phase-field approach which incorporates both heat and solute equations for simulation of Al-Cu binary alloy solidification is studied. The dependence of dendritic growth behavior on intentionally varied thermal diffusivity Dris investigated. The calculated results indicate that with the decrease of the thermal diffusivity DT, the influence of the release of latent heat on the original temperature field decreases, the undercoolins in The melt can maintain relatively steady; while the dendritic lip velocity increases, the dendritic morphology presents more developed side-branches, and the solute segregation is small accordingly. The simulation results are compared with those obtained experimentally; they agree well with each other.
A phase-field approach which incorporates both heat and solute equations for simulation of Al-Cu binary alloy solidification is studied. The dependence of dendritic growth behavior on intentionally varied thermal diffusivity Dris investigated. The calculated results indicate that with the decrease of the thermal diffusivity DT, the influence of the release of latent heat on the original temperature field decreases, the undercoolins in The melt can maintain relatively steady; while the dendritic lip velocity increases, the dendritic morphology presents more developed side-branches, and the solute segregation is small accordingly. The simulation results are compared with those obtained experimentally; they agree well with each other.
2005, 34(10):1574-1577.
Abstract:
The effect of pack aluminizing fillers (Al2O3, Y2O3) on the aluminide coatings are studied by changing the traditional pack aluminizing. The phases and the surface morphologies of aluminide coatings before and after oxidation are examined by XRD and SEM. The results show that the pack aluminizing fillers take part in the aluminizing process, which does not only keep the Al power from sintering, but also affect the phases in the aluminide coatings. The aluminide coatings with the pack aluminizing fillers (Al2O3) are mainly composed of Al3Ti + AlTi + AlTi3 phase, but mainly of AlTi3 phase when the pack aluminizing fillers contain Y2O3, which conflicts with the traditional mechanism of pack aluminizing. The pack aluminizing fillers also have much effect on the surface morphologies of aluminide coatings before and after oxidation and the style of Al2O3 crystal lattice.
The effect of pack aluminizing fillers (Al2O3, Y2O3) on the aluminide coatings are studied by changing the traditional pack aluminizing. The phases and the surface morphologies of aluminide coatings before and after oxidation are examined by XRD and SEM. The results show that the pack aluminizing fillers take part in the aluminizing process, which does not only keep the Al power from sintering, but also affect the phases in the aluminide coatings. The aluminide coatings with the pack aluminizing fillers (Al2O3) are mainly composed of Al3Ti + AlTi + AlTi3 phase, but mainly of AlTi3 phase when the pack aluminizing fillers contain Y2O3, which conflicts with the traditional mechanism of pack aluminizing. The pack aluminizing fillers also have much effect on the surface morphologies of aluminide coatings before and after oxidation and the style of Al2O3 crystal lattice.
2005, 34(10):1578-1581.
Abstract:
采用共溅射方法存玻璃基片上制备了（FePt）1-xCux合金薄膜，FePt合金中添加Cu可以有效降低退火温度，（FePt）1-xCux（x=19．5％）在350℃退火后可以使面内矫顽力Hc〃，达到200kA／m，垂直矫顽力Hc⊥达到280kA／m左右，而纯FePt仅有几千A／m。X射线衍射结果表明退火后形成的FePtCu三元合金是降低退火温度的主要原因。剩磁曲线分析表明Cu的加入不能明显降低晶粒间交换耦合作用。（FePt）1-xCux在400℃退火可以得到10^-24m^3的磁激活体积。
采用共溅射方法存玻璃基片上制备了（FePt）1-xCux合金薄膜，FePt合金中添加Cu可以有效降低退火温度，（FePt）1-xCux（x=19．5％）在350℃退火后可以使面内矫顽力Hc〃，达到200kA／m，垂直矫顽力Hc⊥达到280kA／m左右，而纯FePt仅有几千A／m。X射线衍射结果表明退火后形成的FePtCu三元合金是降低退火温度的主要原因。剩磁曲线分析表明Cu的加入不能明显降低晶粒间交换耦合作用。（FePt）1-xCux在400℃退火可以得到10^-24m^3的磁激活体积。
2005, 34(10):1582-1584.
Abstract:
研究了用部分Ca取代LPC（LPC为无钕镧镨铈混合稀土金属），同时用部分Ni取代Mg的（LPCCa）2（MgNi）17合金的吸放氢性能。比较了不同温度下，不同成分配比对合金贮氢性能的影响。其中，（LPC）1.9Ca0.1Mg15Ni2合金具有相对较低的放氢温度和较大的放氢节，住275℃的放氢量达3．43％（质量分数）。分析了（LPC）1.9Ca0.1Mg15Ni2的微观结构，同时对合金放氢温度降低的原冈进行了讨论。
研究了用部分Ca取代LPC（LPC为无钕镧镨铈混合稀土金属），同时用部分Ni取代Mg的（LPCCa）2（MgNi）17合金的吸放氢性能。比较了不同温度下，不同成分配比对合金贮氢性能的影响。其中，（LPC）1.9Ca0.1Mg15Ni2合金具有相对较低的放氢温度和较大的放氢节，住275℃的放氢量达3．43％（质量分数）。分析了（LPC）1.9Ca0.1Mg15Ni2的微观结构，同时对合金放氢温度降低的原冈进行了讨论。
2005, 34(10):1585-1587.
Abstract:
In the text, a commercial software ANSYS was used to simulate hot-push forming technology on TA2 titanium ring pipe Concave edge strain and stress, convex edge strain and stress, flank edge strain and stress even the change of wall thickness during deformation were studied. It is shown that equivalent stress is enlarge with the bending angle in bending deformation; equivalent strain in concave edge is greater than that of convex edge and the value of equivalent strain is enlarge with the bending angle; In the bending deformation, the bending radius is small and the bending deformation is large. As a result, the thickness of concave edge is thickening which received the compress stress and that of convex edge is reducing which received tensile stress. The conclusion of numerical simulation and test are accordant.
In the text, a commercial software ANSYS was used to simulate hot-push forming technology on TA2 titanium ring pipe Concave edge strain and stress, convex edge strain and stress, flank edge strain and stress even the change of wall thickness during deformation were studied. It is shown that equivalent stress is enlarge with the bending angle in bending deformation; equivalent strain in concave edge is greater than that of convex edge and the value of equivalent strain is enlarge with the bending angle; In the bending deformation, the bending radius is small and the bending deformation is large. As a result, the thickness of concave edge is thickening which received the compress stress and that of convex edge is reducing which received tensile stress. The conclusion of numerical simulation and test are accordant.
2005, 34(10):1588-1591.
Abstract:
An investigation was conducted to determine the causes of weld defects in laser Be/Al weldments. In agreement with earlier studies, features on the fracture surfaces consistent with hot shortness cracking were observed. In this paper, conduction mode welds and keyhole mode welds were used to produce specimens. Closer examination of the fusion zone crack regions reveals the cracking is a result of thermal stress, shape of welds root and impurities segregation. The defects type relate to the weld parameters, the cracks nucleate easily at conduction mode weld, and the blowholes appear easily in keyhole mode weld.
An investigation was conducted to determine the causes of weld defects in laser Be/Al weldments. In agreement with earlier studies, features on the fracture surfaces consistent with hot shortness cracking were observed. In this paper, conduction mode welds and keyhole mode welds were used to produce specimens. Closer examination of the fusion zone crack regions reveals the cracking is a result of thermal stress, shape of welds root and impurities segregation. The defects type relate to the weld parameters, the cracks nucleate easily at conduction mode weld, and the blowholes appear easily in keyhole mode weld.
2005, 34(10):1592-1596.
Abstract:
In this paper, a mechanism of self-propagating high-temperature synthesis of TiC-Ti composite was studied by means of a combustion wave front quenching method in which all information about a process of a phase transitions and a process of a microstructural evolution were remained in the quenched sample. The product was analyzed by X-ray diffraction (XRD), and the process of a microstructural evolution was investigated using scanning electron microscope (SEM) and energy dispersive X-ray (EDX). Based on these experimental results, the mechanism of self-propagating high-temperature synthesis of TiC-Ti cermets was discussed. The experimental results show that the mechanism of SHS of TiC-Ti can be described with a dissolution-precipitation mechanism. The Ti powders melt firstly, and the C particles dissolve in the Ti liquid. C atoms react with Ti and became TiCx. And with the temperature rising, the TiCx particles melt and form Ti-C liquid. As the temperature decreasing, the small TiC particles precipitate from the Ti-C liquid. In the end, a great amount of TiC precipitate from the Ti-C liquid and aggregate. The final products are composed of TiC particles and Ti matrix.
In this paper, a mechanism of self-propagating high-temperature synthesis of TiC-Ti composite was studied by means of a combustion wave front quenching method in which all information about a process of a phase transitions and a process of a microstructural evolution were remained in the quenched sample. The product was analyzed by X-ray diffraction (XRD), and the process of a microstructural evolution was investigated using scanning electron microscope (SEM) and energy dispersive X-ray (EDX). Based on these experimental results, the mechanism of self-propagating high-temperature synthesis of TiC-Ti cermets was discussed. The experimental results show that the mechanism of SHS of TiC-Ti can be described with a dissolution-precipitation mechanism. The Ti powders melt firstly, and the C particles dissolve in the Ti liquid. C atoms react with Ti and became TiCx. And with the temperature rising, the TiCx particles melt and form Ti-C liquid. As the temperature decreasing, the small TiC particles precipitate from the Ti-C liquid. In the end, a great amount of TiC precipitate from the Ti-C liquid and aggregate. The final products are composed of TiC particles and Ti matrix.
2005, 34(10):1597-1600.
Abstract:
The structure and properties of Ti-B-N coatings prepared by radio-frequency plasma-enhanced chemical vapor deposition (rf-PCVD) have been investigated in this work. The coatings were characterized by energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and optical microscopy. Ball-on-disk tribometer and microscopic hardness tester were employed in evaluating the mechanical properties of the coatings. The results show that the structure of the coatings is a nanocomposite, where nanocrystalline TiN is embedded in the amorphous BN and TiB2 matrix. Compared with TiN coatings, the micro-hardness of Ti-B-N coatings can reach 40 GPa. The wear resistances of Ti-B-N coatings remarkably increase with a certain addition of boron, which caused the change of friction mechanism of TiN coatings, although its friction coefficient is higher than that of TiN.
The structure and properties of Ti-B-N coatings prepared by radio-frequency plasma-enhanced chemical vapor deposition (rf-PCVD) have been investigated in this work. The coatings were characterized by energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and optical microscopy. Ball-on-disk tribometer and microscopic hardness tester were employed in evaluating the mechanical properties of the coatings. The results show that the structure of the coatings is a nanocomposite, where nanocrystalline TiN is embedded in the amorphous BN and TiB2 matrix. Compared with TiN coatings, the micro-hardness of Ti-B-N coatings can reach 40 GPa. The wear resistances of Ti-B-N coatings remarkably increase with a certain addition of boron, which caused the change of friction mechanism of TiN coatings, although its friction coefficient is higher than that of TiN.
2005, 34(10):1601-1604.
Abstract:
Nano-Mo-La2O3 power with the average grain size being about sixty nanometers was prepared by the sol-gel. Mo-La2O3 electrical contact material was fabricated by hot pressure sintering. It is found that the electrical contact material is uniform, La2O3 particles were distributed around the grain boundary or in the crystal, and the average grain size of the particles are mostly less than one hundred nanometer. After breakdown tests, the breakdown points distribute around the whole face, the electron erosion is shallow, and the electron erosion firstly occurred in the La2O3 phase.
Nano-Mo-La2O3 power with the average grain size being about sixty nanometers was prepared by the sol-gel. Mo-La2O3 electrical contact material was fabricated by hot pressure sintering. It is found that the electrical contact material is uniform, La2O3 particles were distributed around the grain boundary or in the crystal, and the average grain size of the particles are mostly less than one hundred nanometer. After breakdown tests, the breakdown points distribute around the whole face, the electron erosion is shallow, and the electron erosion firstly occurred in the La2O3 phase.
2005, 34(10):1605-1608.
Abstract:
An ingot of Nb based in-situ composites (NBISC) was produced by a vacuum self-consuming arc melting furnace. The directionally solidified samples were prepared by an electron beam floating zone melting (EBFZM) furnace with a high temperature gradient, and their microstructural characteristics were analyzed. The results show that the microstructure of as-cast NBISC is composed of primary dendrites of Nb solid solution (Nbss) and the eutectic colonies of Nbss plus (Nb,Ti)3Si/(Nb,Ti)5Si 3. In the EBFZM furnace, with the increase of withdrawing rate, the eutectic microstructure of NBISC is refined. The amount of eutectic colonies layers increases. The sizes of (Nb,Ti)3Si/(Nb,Ti)5Si3 lumps or plates decrease and their amount increases. Their morphology tends to more regular, and the distribution becomes more homogeneous. The directionality becomes intensive and the directionally solidified effects are remarkable.
An ingot of Nb based in-situ composites (NBISC) was produced by a vacuum self-consuming arc melting furnace. The directionally solidified samples were prepared by an electron beam floating zone melting (EBFZM) furnace with a high temperature gradient, and their microstructural characteristics were analyzed. The results show that the microstructure of as-cast NBISC is composed of primary dendrites of Nb solid solution (Nbss) and the eutectic colonies of Nbss plus (Nb,Ti)3Si/(Nb,Ti)5Si 3. In the EBFZM furnace, with the increase of withdrawing rate, the eutectic microstructure of NBISC is refined. The amount of eutectic colonies layers increases. The sizes of (Nb,Ti)3Si/(Nb,Ti)5Si3 lumps or plates decrease and their amount increases. Their morphology tends to more regular, and the distribution becomes more homogeneous. The directionality becomes intensive and the directionally solidified effects are remarkable.
2005, 34(10):1609-1612.
Abstract:
采用粉末冶金方法，通过Ti与Cr3C2反应原位生成TiC颗粒增强钛基复合材料。利用X射线衍射（XRD）、透射电镜（TEM）等手段对其相组成和显微组织进行了研究。结果表明：通过Ti与Cr3C2反应能够原位生成TiC颗粒，生成的TiC颗粒呈多角状，粒度在几十纳米到50μm范围内；Cr3C2中的Cr固溶在Ti基体中，使基体由α＋β两相合金转变成为亚稳态β型钛合金。
采用粉末冶金方法，通过Ti与Cr3C2反应原位生成TiC颗粒增强钛基复合材料。利用X射线衍射（XRD）、透射电镜（TEM）等手段对其相组成和显微组织进行了研究。结果表明：通过Ti与Cr3C2反应能够原位生成TiC颗粒，生成的TiC颗粒呈多角状，粒度在几十纳米到50μm范围内；Cr3C2中的Cr固溶在Ti基体中，使基体由α＋β两相合金转变成为亚稳态β型钛合金。
2005, 34(10):1613-1616.
Abstract:
The microstructure of the explosively compacted Nd-Fe-B permanent magnets has been investigated by means of TEM and XRD. It is shown that there are three kinds of phases: matrix Nd2Fe14B, O-rich phases and Nd-rich phase with different structures and compositions in explosively compacted Nd-Fe-B permanent magnets. Matrix Nd2Fe14B is predominantly the hard Nd2Fe14B phase with lattice parameters of a=0.88 nm and c=1.22 nm. The O-rich phase presented at the two-grain boundaries and three-grain junctions, with fcc structures, and lattice parameter is a=0.559 nm. The O-rich phase belong to the compound Nd-Fe-O, and contents of O, Nd and Fe are 56at%, 22at% and 21at%, respectively. It is also shown that a large number of the block-shaped Nd-rich phases are in the two-grain boundary or three-grain junctions or Nd2Fe14B phases, with hcp structure and lattice parameters of a=0.395 nm and c=0.628 nm. The Nd-rich phases belong to compound Nd-O, and contents of Nd and O are 85at% and 12at%, respectively. Also a few dislocations in the boundary phases have been observed.
The microstructure of the explosively compacted Nd-Fe-B permanent magnets has been investigated by means of TEM and XRD. It is shown that there are three kinds of phases: matrix Nd2Fe14B, O-rich phases and Nd-rich phase with different structures and compositions in explosively compacted Nd-Fe-B permanent magnets. Matrix Nd2Fe14B is predominantly the hard Nd2Fe14B phase with lattice parameters of a=0.88 nm and c=1.22 nm. The O-rich phase presented at the two-grain boundaries and three-grain junctions, with fcc structures, and lattice parameter is a=0.559 nm. The O-rich phase belong to the compound Nd-Fe-O, and contents of O, Nd and Fe are 56at%, 22at% and 21at%, respectively. It is also shown that a large number of the block-shaped Nd-rich phases are in the two-grain boundary or three-grain junctions or Nd2Fe14B phases, with hcp structure and lattice parameters of a=0.395 nm and c=0.628 nm. The Nd-rich phases belong to compound Nd-O, and contents of Nd and O are 85at% and 12at%, respectively. Also a few dislocations in the boundary phases have been observed.
26 Study on the Nano-Crystalline and Amorphous Al-Pb Series Powders Synthesized by Mechanical Alloying
2005, 34(10):1617-1621.
Abstract:
采用X射线符亍射（XRD）、透射电镜（TEM）研究了球料比为8：1、转速280r／min和球料比为25：1、转速450r／min条件下绛不同球磨时间后混合粉末的相变、晶粒大小和微观形貌等。结果表明：通过机械合金化可以制备出Al-15％Pb-4％Si-1％Sn-1．5％Cu纳米晶粉未，而且球磨导致了合金粉体非晶化，在球磨过程中混合粉体首先细化、合金化和纳米晶化，然后部分纳米晶转变为非晶；在机械合金化过程中球料比越大、转速越高，即给球磨系统供给的能量越大，则混合粉末获得纳米晶的时间越短：基于多层非晶化模型讨论了△Hmin≈1.34的情况下Al-Pb非晶形成的机制，指出在机械合金化过程中Al-Pb非晶形成并非需要△Hmin〈〈0，其非晶化驱动力主要由浓度梯度提供。
采用X射线符亍射（XRD）、透射电镜（TEM）研究了球料比为8：1、转速280r／min和球料比为25：1、转速450r／min条件下绛不同球磨时间后混合粉末的相变、晶粒大小和微观形貌等。结果表明：通过机械合金化可以制备出Al-15％Pb-4％Si-1％Sn-1．5％Cu纳米晶粉未，而且球磨导致了合金粉体非晶化，在球磨过程中混合粉体首先细化、合金化和纳米晶化，然后部分纳米晶转变为非晶；在机械合金化过程中球料比越大、转速越高，即给球磨系统供给的能量越大，则混合粉末获得纳米晶的时间越短：基于多层非晶化模型讨论了△Hmin≈1.34的情况下Al-Pb非晶形成的机制，指出在机械合金化过程中Al-Pb非晶形成并非需要△Hmin〈〈0，其非晶化驱动力主要由浓度梯度提供。
2005, 34(10):1622-1626.
Abstract:
Taking the process of producing MIM Ti-6Al-4V alloy by HDH powder as a reference, the processes of making P/M Ti-6Al-4V and MIM Ti-6Al-4V by using TiH2 have been discussed. When using HDH Ti powder making MIM Ti-6Al-4V the tensile strength is 819 MPa and elongation percentage is 7%. When using TiH2 powder making P/M Ti-6Al-4V the tensile strength is over 850 MPa. And when using TiH2 powder making MIM Ti-6Al-4V, processes of dehydrogenation and debinding are successfully reached.
Taking the process of producing MIM Ti-6Al-4V alloy by HDH powder as a reference, the processes of making P/M Ti-6Al-4V and MIM Ti-6Al-4V by using TiH2 have been discussed. When using HDH Ti powder making MIM Ti-6Al-4V the tensile strength is 819 MPa and elongation percentage is 7%. When using TiH2 powder making P/M Ti-6Al-4V the tensile strength is over 850 MPa. And when using TiH2 powder making MIM Ti-6Al-4V, processes of dehydrogenation and debinding are successfully reached.
2005, 34(10):1627-1632.
Abstract:
The experimcnts of coatirtuous casting and directional solidifing titanium ahoy slabs were performed in a multi-functional electromagnetic casting apparatus with rectangular cold crucible. The influences of process parameters were evaluated on the surface qualities and macrostructures of the casting slabs. It is shown that the surface variations of the slabs get to be well with the increasing of the number of coil turns and the input power. While, it seems to be bad with the increase of the withdrawal velocity and the reduce of the relative position of dummy to the induction coils. The limits of influence of process parameters are deduced as that the first one is the induction coil, the second one is the input power, the third one is the withdrawal velocity, and the last one is the dummy position. With the selective optimized parameters, the slabs free from cracks and ripples are obtained under the experimental conditions. It is interpreted that the variations of meniscus volumes has the significant effects on the casting process, which in turn to be the results of surface qualities of cast slabs. With the increasing of the number of induction coil turns and the decreasing of the withdrawal velocities, the numbers of grains reduced and the grains are parallel to the growth direction. The slabs with both good surface quality and uni-directional macrostructure were cast in cold crucible whose cross section is approximately rectangular.
The experimcnts of coatirtuous casting and directional solidifing titanium ahoy slabs were performed in a multi-functional electromagnetic casting apparatus with rectangular cold crucible. The influences of process parameters were evaluated on the surface qualities and macrostructures of the casting slabs. It is shown that the surface variations of the slabs get to be well with the increasing of the number of coil turns and the input power. While, it seems to be bad with the increase of the withdrawal velocity and the reduce of the relative position of dummy to the induction coils. The limits of influence of process parameters are deduced as that the first one is the induction coil, the second one is the input power, the third one is the withdrawal velocity, and the last one is the dummy position. With the selective optimized parameters, the slabs free from cracks and ripples are obtained under the experimental conditions. It is interpreted that the variations of meniscus volumes has the significant effects on the casting process, which in turn to be the results of surface qualities of cast slabs. With the increasing of the number of induction coil turns and the decreasing of the withdrawal velocities, the numbers of grains reduced and the grains are parallel to the growth direction. The slabs with both good surface quality and uni-directional macrostructure were cast in cold crucible whose cross section is approximately rectangular.
2005, 34(10):1633-1636.
Abstract:
研究了二级回火工艺对Nd12.0Dy28Fe747Co34Cu0.2B6.9磁体磁性能和微结构的影响。研究结果表明：二级回火对磁体的剩磁和磁能积影响很小，内禀矫顽力Hcj随二级回火温度升高而增大，在480℃时达到最大；高于480℃后，风随二级回火温度的升高而迅速下降；存480℃二级回火时，执随回火时间的增加而增大，经2h回火达到最大；大于2h后，回火时间的进一步增加对Hcj影响很小；480℃二级回火2h时磁体主相晶粒边界光滑，富稀土相在晶界分布连续、均匀。
研究了二级回火工艺对Nd12.0Dy28Fe747Co34Cu0.2B6.9磁体磁性能和微结构的影响。研究结果表明：二级回火对磁体的剩磁和磁能积影响很小，内禀矫顽力Hcj随二级回火温度升高而增大，在480℃时达到最大；高于480℃后，风随二级回火温度的升高而迅速下降；存480℃二级回火时，执随回火时间的增加而增大，经2h回火达到最大；大于2h后，回火时间的进一步增加对Hcj影响很小；480℃二级回火2h时磁体主相晶粒边界光滑，富稀土相在晶界分布连续、均匀。
2005, 34(10):1637-1641.
Abstract:
ITO films were prepared by r.f. magnetron sputtering, and were annealed in ammonia, nitrogen and air atmosphere respectively. The annealing effects on electrical and optical properties of ITO films under different atmospheres were studied using X-ray diffraction (XRD), Hall Effect and UV-VIS-NIR spectrometer. The transmission of ITO films is greatly improved by the heat treatments in all atmospheres. The electrical properties of ITO films annealed in ammonia are better than in other two atmospheres.
ITO films were prepared by r.f. magnetron sputtering, and were annealed in ammonia, nitrogen and air atmosphere respectively. The annealing effects on electrical and optical properties of ITO films under different atmospheres were studied using X-ray diffraction (XRD), Hall Effect and UV-VIS-NIR spectrometer. The transmission of ITO films is greatly improved by the heat treatments in all atmospheres. The electrical properties of ITO films annealed in ammonia are better than in other two atmospheres.
2005, 34(10):1642-1645.
Abstract:
采用静电白组装工艺存玻璃衬底上制备了TiO2薄膜，研究其在波长为254nm和365nm的紫外光及可见光等不同光源照射下杀灭大肠杆菌的性能。抗菌实验结果表明：254nm波长的紫外光本身具有较强的杀菌作用，不宜在TiO2薄膜光催化杀菌实验中作为实验光源；在365nm波长的紫外光激发下，静电自组装TiO2薄膜有较好的杀菌效果，365nm紫外光本身对细菌的杀灭作用较弱；静电自组装制得的TiO2薄膜经可见光光源（光强81．7μW／cm^2）照射8h后，对大肠杆菌的杀菌率可达91．1％。
采用静电白组装工艺存玻璃衬底上制备了TiO2薄膜，研究其在波长为254nm和365nm的紫外光及可见光等不同光源照射下杀灭大肠杆菌的性能。抗菌实验结果表明：254nm波长的紫外光本身具有较强的杀菌作用，不宜在TiO2薄膜光催化杀菌实验中作为实验光源；在365nm波长的紫外光激发下，静电自组装TiO2薄膜有较好的杀菌效果，365nm紫外光本身对细菌的杀灭作用较弱；静电自组装制得的TiO2薄膜经可见光光源（光强81．7μW／cm^2）照射8h后，对大肠杆菌的杀菌率可达91．1％。
Zhang Gaohui
,
Zhang Pingze
,
Pan Junde
,
Gao Yuan
,
Xu Zhong Taivuan University of Technology Taivuan
,
China)
2005, 34(10):1646-1649.
Abstract:
Using the double glow plasma metallulgy principle improve the tribological properties of Ti6Al4V. A high pure solid honeycomb graphite was taken as source cathode, titanium alloy Ti6Al4V as cathode, high pure argon and nitrogen gas as working gas, The carbonitriding Iayer with special physical and chemical properties was prepared on the surface of Ti6Al4V. The phase compositions and C. N, Ti distribution in carbonitriding layer were determined by means of XRD and glow discharge spectrometry. The surface layer microhardness distribution was measured gradually from surface to inner. Microhardness of surface increased more than two times. Results from friction and wear test show thai the wear resistance property of TifAl4V alloy is improved evidently.
Using the double glow plasma metallulgy principle improve the tribological properties of Ti6Al4V. A high pure solid honeycomb graphite was taken as source cathode, titanium alloy Ti6Al4V as cathode, high pure argon and nitrogen gas as working gas, The carbonitriding Iayer with special physical and chemical properties was prepared on the surface of Ti6Al4V. The phase compositions and C. N, Ti distribution in carbonitriding layer were determined by means of XRD and glow discharge spectrometry. The surface layer microhardness distribution was measured gradually from surface to inner. Microhardness of surface increased more than two times. Results from friction and wear test show thai the wear resistance property of TifAl4V alloy is improved evidently.
2005, 34(10):1650-1652.
Abstract:
为探索适于中温条件下使用的固体氧化物燃料电池的阴极材料,用甘氨酸-硝酸盐法(GNP法)制备了Gd0.8Sr0.2CoO3(GSC)阴极粉体,用X-ray衍射考察了GSC的成相温度.采用丝网印刷法将GSC沉积在(Sm2O3)0.2(CeO2)0.8(SDC)圆片上,制成对称阴极,在不同温度下烧结.用交流阻抗谱从500℃到750℃测量了GSC阴极和SDC电解质之间的界面电阻.结果表明,用甘氨酸-硝酸盐法制备的GSC粉体的成相温度比传统固相法降低了400℃～500℃;700℃时,GSC阴极的界面电阻仅为0.26 Ω·cm2.
为探索适于中温条件下使用的固体氧化物燃料电池的阴极材料,用甘氨酸-硝酸盐法(GNP法)制备了Gd0.8Sr0.2CoO3(GSC)阴极粉体,用X-ray衍射考察了GSC的成相温度.采用丝网印刷法将GSC沉积在(Sm2O3)0.2(CeO2)0.8(SDC)圆片上,制成对称阴极,在不同温度下烧结.用交流阻抗谱从500℃到750℃测量了GSC阴极和SDC电解质之间的界面电阻.结果表明,用甘氨酸-硝酸盐法制备的GSC粉体的成相温度比传统固相法降低了400℃～500℃;700℃时,GSC阴极的界面电阻仅为0.26 Ω·cm2.
Wang Jingyi
,
Yin Sheng
,
Tao Futing
,
Wu Jingbo
,
Feng Xinhua
,
Su Rui
,
Xu Shuhui
,
Chen Zhengjiang
,
Chen Wenhui
,
Luo Wenguang
,
2005, 34(10):1653-1656.
Abstract:
According to the purity requirement for Si powder, a cold plasma reaction chamber with long drop distance and high reaction rate is provided in the paper. In the selection of technology parameter, we put stress on increasing the thickness of sheath, raising the densities of reaction particles, and controlling the speed of pump. The purifying rate, collective ratio, and drop time of Si powder were raised effectively as a consequence of these selections. The experimental results show that solar grade Si (4N) can be gotten from industrial Si (Melatturgical grade Si-2N) in the plasma system.
According to the purity requirement for Si powder, a cold plasma reaction chamber with long drop distance and high reaction rate is provided in the paper. In the selection of technology parameter, we put stress on increasing the thickness of sheath, raising the densities of reaction particles, and controlling the speed of pump. The purifying rate, collective ratio, and drop time of Si powder were raised effectively as a consequence of these selections. The experimental results show that solar grade Si (4N) can be gotten from industrial Si (Melatturgical grade Si-2N) in the plasma system.
2005, 34(10):1657-1660.
Abstract:
The ternary metal silicide Co3Mo2Si is expected to be a promising wear resistant material due to its inherent high hardness, strong anomalous hardness-temperature dependence and covalent-dominated strong atomic bonds. Poor ductility from room to intermediate high temperatures is currently the main obstacle preventing it from practical industrial applications. In order to improve the ductility of Co3Mo2Si ternary metal silicide, Co solid solution toughened Co3Mo2Si ternary metal silicide alloys were designed and fabricated by the laser melting/deposition process. As-solidification microstructure of the Co/Co3Mo2Si metal silicide alloys was characterized by optical microscopy (OM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Vickers microhardness measurement as a function of Co content. The Co/Co3Mo2Si ternary metal silicide alloys have a dense and uniform microstructure consisting of the Co3Mo2Si primary dendrites and the interdendritic Co/Co3Mo2Si eutectics. Volume fraction of Co3Mo2Si primary dendrites (72%~92%) and the average hardness (8000 MPa~11 000 MPa) of the alloys decrease with the increase of Co content. Compared with the single-phase Co3Mo2Si ternary metal silicide, the Co toughened Co3Mo2Si alloys have excellent balance of strength and ductility, which was attributed to the effective toughening of ductile cobalt solid solution.
The ternary metal silicide Co3Mo2Si is expected to be a promising wear resistant material due to its inherent high hardness, strong anomalous hardness-temperature dependence and covalent-dominated strong atomic bonds. Poor ductility from room to intermediate high temperatures is currently the main obstacle preventing it from practical industrial applications. In order to improve the ductility of Co3Mo2Si ternary metal silicide, Co solid solution toughened Co3Mo2Si ternary metal silicide alloys were designed and fabricated by the laser melting/deposition process. As-solidification microstructure of the Co/Co3Mo2Si metal silicide alloys was characterized by optical microscopy (OM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Vickers microhardness measurement as a function of Co content. The Co/Co3Mo2Si ternary metal silicide alloys have a dense and uniform microstructure consisting of the Co3Mo2Si primary dendrites and the interdendritic Co/Co3Mo2Si eutectics. Volume fraction of Co3Mo2Si primary dendrites (72%~92%) and the average hardness (8000 MPa~11 000 MPa) of the alloys decrease with the increase of Co content. Compared with the single-phase Co3Mo2Si ternary metal silicide, the Co toughened Co3Mo2Si alloys have excellent balance of strength and ductility, which was attributed to the effective toughening of ductile cobalt solid solution.
2005, 34(10):1661-1665.
Abstract:
采用DTA研究了喷雾干燥-H2还原法制备的纳米级90W-7Ni-3Fe复合粉末随温度升高时熔点和相的变化，依此为根据研究了试样存不同烧结温度和小同烧结时间下的烧结特性。采用扫描电子显微镜和金相仪分别对试样断口进行了形貌观察和W晶粒测试，并对烧结样的性能进行了测定与分析。研究结果表明：保温时间为120min时，随着烧结温度的提高，试样的性能有了显著的变化，当烧结温度为1390℃时，试样的抗拉强度、延伸率和相对密度都达到一个极大值，分别为888.3MPa，12．9％和99．0％：当烧结温度为1390℃时，随烧结时间的延长，试样的性能也有显著的变化，试样的抗拉强度、延伸牢和相对密度存保温120min时都达到一个极大值：平均W晶粒度为20um，W晶粒呈球形或近球形；复合粉末烧结活性高，比传统烧结温度降低80℃；粉末中高的氧含量和在干氢中的烧结，使得试样在液相烧结时容易出现孔洞和气泡，W晶粒和粘结相分布不均匀，致使试样力学性能偏低。
采用DTA研究了喷雾干燥-H2还原法制备的纳米级90W-7Ni-3Fe复合粉末随温度升高时熔点和相的变化，依此为根据研究了试样存不同烧结温度和小同烧结时间下的烧结特性。采用扫描电子显微镜和金相仪分别对试样断口进行了形貌观察和W晶粒测试，并对烧结样的性能进行了测定与分析。研究结果表明：保温时间为120min时，随着烧结温度的提高，试样的性能有了显著的变化，当烧结温度为1390℃时，试样的抗拉强度、延伸率和相对密度都达到一个极大值，分别为888.3MPa，12．9％和99．0％：当烧结温度为1390℃时，随烧结时间的延长，试样的性能也有显著的变化，试样的抗拉强度、延伸牢和相对密度存保温120min时都达到一个极大值：平均W晶粒度为20um，W晶粒呈球形或近球形；复合粉末烧结活性高，比传统烧结温度降低80℃；粉末中高的氧含量和在干氢中的烧结，使得试样在液相烧结时容易出现孔洞和气泡，W晶粒和粘结相分布不均匀，致使试样力学性能偏低。
2005, 34(10):1666-1668.
Abstract:
A new silver-rare earth oxide contact material, Ag/SnO2-La2O3-Bi2O3, has been produced using powder metallurgy method. The microstructure of Ag/SnO2-La2O3-Bi2O3 was analyzed using SEM and EDS. The new contact material was tested through temperature rise, make-break capacity testing and arc erosion. The new contact material passes the make-break capacity testing, its temperature rise is similar to that of Ag/CdO and the average arc erosion of make contact is only 2/3 that of Ag/CdO. At last, the cost of Ag/SnO2-La2O3-Bi2O3 and Ag/CdO is analyzed. From the testing results and the cost analysis, the new material has preferable physics, mechanism and electric behavior and lower cost. The new innocuity contact material may be substituted for Ag/CdO because of its preferable application foreground and economy benefit.
A new silver-rare earth oxide contact material, Ag/SnO2-La2O3-Bi2O3, has been produced using powder metallurgy method. The microstructure of Ag/SnO2-La2O3-Bi2O3 was analyzed using SEM and EDS. The new contact material was tested through temperature rise, make-break capacity testing and arc erosion. The new contact material passes the make-break capacity testing, its temperature rise is similar to that of Ag/CdO and the average arc erosion of make contact is only 2/3 that of Ag/CdO. At last, the cost of Ag/SnO2-La2O3-Bi2O3 and Ag/CdO is analyzed. From the testing results and the cost analysis, the new material has preferable physics, mechanism and electric behavior and lower cost. The new innocuity contact material may be substituted for Ag/CdO because of its preferable application foreground and economy benefit.
2005, 34(10):1669-1672.
Abstract:
以乙醇为分散剂和保护剂，采用反向化学共沉淀法，制备了Y2O3-ZrO2纳米晶。结果表明：所制备的纳米晶为说办晶系；Y2O3-ZrO2纳米晶呈球形，当焙烧温度为900℃时，粒予粒径约30nm，粒径分布均匀，无明显硬团聚体存在；Y2O3-ZrO2纳米晶为多晶结构：Y2O3-ZrO2的晶化温度为489．19℃；Y2O3-ZrO2纳米晶的相对密度随粒径增大而增大。
以乙醇为分散剂和保护剂，采用反向化学共沉淀法，制备了Y2O3-ZrO2纳米晶。结果表明：所制备的纳米晶为说办晶系；Y2O3-ZrO2纳米晶呈球形，当焙烧温度为900℃时，粒予粒径约30nm，粒径分布均匀，无明显硬团聚体存在；Y2O3-ZrO2纳米晶为多晶结构：Y2O3-ZrO2的晶化温度为489．19℃；Y2O3-ZrO2纳米晶的相对密度随粒径增大而增大。
2005, 34(10):1673-1676.
Abstract:
采用改进水热法（金属Ti片与等浓度的Ba^2＋，Sr^2＋强碱性溶液于250℃水热反应5h，然后经过600℃，0．5h烧结处理）制备了单一立方相的Ba0．5Sr0．5TiO3薄膜。制备的Ba0．5Sr0．5TiO3薄膜通过XRD，SEM和XPS进行表征分析。结果表明：600℃下经过0．5h烧绘处理的Ba0．5Sr0．5TiO3薄膜结晶更完整：同时，制备的Ba0．5Sr0．5TiO3薄膜表面吸附有OH，经过10min刻蚀处理后，吸附的OH能谱峰消失。
采用改进水热法（金属Ti片与等浓度的Ba^2＋，Sr^2＋强碱性溶液于250℃水热反应5h，然后经过600℃，0．5h烧结处理）制备了单一立方相的Ba0．5Sr0．5TiO3薄膜。制备的Ba0．5Sr0．5TiO3薄膜通过XRD，SEM和XPS进行表征分析。结果表明：600℃下经过0．5h烧绘处理的Ba0．5Sr0．5TiO3薄膜结晶更完整：同时，制备的Ba0．5Sr0．5TiO3薄膜表面吸附有OH，经过10min刻蚀处理后，吸附的OH能谱峰消失。
2005, 34(10):1677-1680.
Abstract:
The metal flowing behavior in welding zone of FS welds has great influence on the welds mechanical performance. The friction stir welding (FSW) of 5 mm thickness plates of 1060 Al/3003 Al was carried out. The flow of metal during FSW was investigated by etching of the nugget in the welding zone of the 1060 Al/3003 Al. The flow visualization was examined in the range of welding parameters. The transverse and horizontal cross section was analyzed. The result shows that the process parameters influence the metal flow visualization greatly. With a high tool rotational speed and a proper welding speed, a steady and well-welded join can be produced.
The metal flowing behavior in welding zone of FS welds has great influence on the welds mechanical performance. The friction stir welding (FSW) of 5 mm thickness plates of 1060 Al/3003 Al was carried out. The flow of metal during FSW was investigated by etching of the nugget in the welding zone of the 1060 Al/3003 Al. The flow visualization was examined in the range of welding parameters. The transverse and horizontal cross section was analyzed. The result shows that the process parameters influence the metal flow visualization greatly. With a high tool rotational speed and a proper welding speed, a steady and well-welded join can be produced.
