Volume 0,Issue 6,2002 Table of Contents
2002(6):403-405.
Abstract:
The criteria for stability of eutectics,solid solutions and precipitates are proposed.It is based on the Thomas-Fermi-Dirac model on the boundary conditions that electr on densities and chemical potentials should be equal in either side of a co mposite film.The optimum condition for stabilizing the energ y balance and the sizes of eutectics o r precipitates is given.
The criteria for stability of eutectics,solid solutions and precipitates are proposed.It is based on the Thomas-Fermi-Dirac model on the boundary conditions that electr on densities and chemical potentials should be equal in either side of a co mposite film.The optimum condition for stabilizing the energ y balance and the sizes of eutectics o r precipitates is given.
2002(6):406-409.
Abstract:
美国高新技术研究所(HTR)采用连续装管成型(CTFF)粉末装管技术(PIT)制备了MgB2/Fe复合线。目前已制备出直径为1.2mm的先驱线(包Fe的Mg+B混合粉),长度达70m。在800℃～950℃处理3min～30min的短样品,传输临界电流密度(Jc)在4K/4T下达到(2～3)×104A/cm2,在4K/2T下达到4×104A/cm2,在4K自场下外推的Jc最少达到2×105A/cm2。用磁测量方法得到的Jc与外推得到的传输临界电流值差不多。
美国高新技术研究所(HTR)采用连续装管成型(CTFF)粉末装管技术(PIT)制备了MgB2/Fe复合线。目前已制备出直径为1.2mm的先驱线(包Fe的Mg+B混合粉),长度达70m。在800℃～950℃处理3min～30min的短样品,传输临界电流密度(Jc)在4K/4T下达到(2～3)×104A/cm2,在4K/2T下达到4×104A/cm2,在4K自场下外推的Jc最少达到2×105A/cm2。用磁测量方法得到的Jc与外推得到的传输临界电流值差不多。
2002(6):410-414.
Abstract:
运用量子化学计算理论，求出了有关化合物的热化学参数，并根据有关热力学模型，计算了金属间化合物Ti2AlNb中元素的活度，由此计算了SCS－6 SiC长纤维增强Ti2AlNb金属间化合物复合材料界面反应的Gibbs函数变值△rG,用△rG判据推测了界面反应产物并与透射电镜实验结果进行了对比分析。研究表明，由于Ti2AlNb中原子结合力较Ti3Al强，因而SCS－6 SiC/Ti2AlNb复合材料的界面反应较SCS－6 SiC/Ti3Al轻。反应初期形成晶粒非常细上的TiC,Ti5Si3,晶粒较大的TiC和Ti3Si是由于元素扩散和反应所形成。在对复合材料的热暴露中，这些反应产物均进一步长大，并由于反应Ti3Al C→Ti3AlC，在Ti2AlNb基体中形成一些三元反应产物Ti3AlC晶粒。
运用量子化学计算理论，求出了有关化合物的热化学参数，并根据有关热力学模型，计算了金属间化合物Ti2AlNb中元素的活度，由此计算了SCS－6 SiC长纤维增强Ti2AlNb金属间化合物复合材料界面反应的Gibbs函数变值△rG,用△rG判据推测了界面反应产物并与透射电镜实验结果进行了对比分析。研究表明，由于Ti2AlNb中原子结合力较Ti3Al强，因而SCS－6 SiC/Ti2AlNb复合材料的界面反应较SCS－6 SiC/Ti3Al轻。反应初期形成晶粒非常细上的TiC,Ti5Si3,晶粒较大的TiC和Ti3Si是由于元素扩散和反应所形成。在对复合材料的热暴露中，这些反应产物均进一步长大，并由于反应Ti3Al C→Ti3AlC，在Ti2AlNb基体中形成一些三元反应产物Ti3AlC晶粒。
2002(6):415-418.
Abstract:
通过对Ag元素掺杂的赝两元合金（PbTe)1-x(SnTe)x(0≤x≤0.4）热电性能进行研究发展，处于本征态的PbTe合金电导率对掺杂较为敏感。但当摩尔分数增大时，赝两元合金（PbTe)1-x(SnTe)x电导率随掺杂量的增大受到抑制，这在高温情况下尤为显著。当温度低于约423K时，掺杂量对PbTe合金的Seebeck系数影响不大；但当温度大于423K时，PbTe合金的Seebeck系数随掺杂量而增大。掺杂量越大，摩尔分数越高，同一合金的Seebeck系数变化越小。热电优值计算表明，掺杂0.02mol%的合金系较适宜于制作成分递变的热电材料（FGM）。
通过对Ag元素掺杂的赝两元合金（PbTe)1-x(SnTe)x(0≤x≤0.4）热电性能进行研究发展，处于本征态的PbTe合金电导率对掺杂较为敏感。但当摩尔分数增大时，赝两元合金（PbTe)1-x(SnTe)x电导率随掺杂量的增大受到抑制，这在高温情况下尤为显著。当温度低于约423K时，掺杂量对PbTe合金的Seebeck系数影响不大；但当温度大于423K时，PbTe合金的Seebeck系数随掺杂量而增大。掺杂量越大，摩尔分数越高，同一合金的Seebeck系数变化越小。热电优值计算表明，掺杂0.02mol%的合金系较适宜于制作成分递变的热电材料（FGM）。
2002(6):419-422.
Abstract:
利用双剪切蠕变试样在受剪切区的筏化试验结果和不同晶体取向试样的蠕变持久寿命试验结果，对镍基单晶合金的蠕变筏化预测模型和蠕变持久寿命模型进行考核，证实此2个模型的合理性。
利用双剪切蠕变试样在受剪切区的筏化试验结果和不同晶体取向试样的蠕变持久寿命试验结果，对镍基单晶合金的蠕变筏化预测模型和蠕变持久寿命模型进行考核，证实此2个模型的合理性。
2002(6):423-426.
Abstract:
采用单辊旋铸技术制备Al-2.5Ti-2.5Fe,Al2.5Ti-2.5Fe-2.5V和Al-2.5Ti-2.5Fe-2.5Cr(at%，下同）合金薄带，利用X射线衍射（XRD）和透射电镜（TEM）分析了这些合金的急冷态和退火态组织。结果表明：快速凝固Al-2.5Ti-2.5Fe合金急冷态组织中存在Al3Ti和Al5Ti2两种初生相，快凝合金经400℃退火10h后，组织中出现了Al13Fe4相，在450℃退火，组织中析出了弥散Al3Ti相；快速凝固Al-2.5Ti-2.5Fe-2.5V合金急冷态组织中存在Al11V相和Al80V20相，400℃退火10h后，初生Al11V相转变为Al80V20相，且固溶在α-Al基体中的Ti,Fe以Al23Ti9相和Al13Fe4相的形式析出；快速凝固Al-2.5Ti-2.5Fe-2.5Cr合金急冷态组织中存在Al3Ti和Al13Cr2两种初生相，快凝合金经300℃退火10h后，组织中析出了Al13Cr2和Al3Ti两种弥散相，400℃退火10h时后组织中出现了Al13Fe4相。
采用单辊旋铸技术制备Al-2.5Ti-2.5Fe,Al2.5Ti-2.5Fe-2.5V和Al-2.5Ti-2.5Fe-2.5Cr(at%，下同）合金薄带，利用X射线衍射（XRD）和透射电镜（TEM）分析了这些合金的急冷态和退火态组织。结果表明：快速凝固Al-2.5Ti-2.5Fe合金急冷态组织中存在Al3Ti和Al5Ti2两种初生相，快凝合金经400℃退火10h后，组织中出现了Al13Fe4相，在450℃退火，组织中析出了弥散Al3Ti相；快速凝固Al-2.5Ti-2.5Fe-2.5V合金急冷态组织中存在Al11V相和Al80V20相，400℃退火10h后，初生Al11V相转变为Al80V20相，且固溶在α-Al基体中的Ti,Fe以Al23Ti9相和Al13Fe4相的形式析出；快速凝固Al-2.5Ti-2.5Fe-2.5Cr合金急冷态组织中存在Al3Ti和Al13Cr2两种初生相，快凝合金经300℃退火10h后，组织中析出了Al13Cr2和Al3Ti两种弥散相，400℃退火10h时后组织中出现了Al13Fe4相。
2002(6):427-431.
Abstract:
Normal penetration of tungsten allo y shells into steel targets was perfo rmed and the total deformation and fr acture history of the shells were successfully obtained.The mic rostructure of received shells was e xamined and analyzed,revealing that the formation of adiabatic shear band at critical section is the mainl y failure behavior of tungsten alloy shell,and matrix rupture at the tip o f internal hollow also results in the damage of the shell.Furthermore,th e failure process of critical sectio n is divided into three steps,i.e.th e formation of adiabatic shear bands,the appearance of micro-cracks in the bands and the expansion of sh ear cracks.In additional,the failu res of tungsten alloy shells start at geometrical stress concentratio n zone in the all received shells,so o nly if the local stress concentratio n coefficients are markedly decreased by shell geometrical design,the tungsten alloy shells can be able to play an important role in several applications,including military engi-neering.
Normal penetration of tungsten allo y shells into steel targets was perfo rmed and the total deformation and fr acture history of the shells were successfully obtained.The mic rostructure of received shells was e xamined and analyzed,revealing that the formation of adiabatic shear band at critical section is the mainl y failure behavior of tungsten alloy shell,and matrix rupture at the tip o f internal hollow also results in the damage of the shell.Furthermore,th e failure process of critical sectio n is divided into three steps,i.e.th e formation of adiabatic shear bands,the appearance of micro-cracks in the bands and the expansion of sh ear cracks.In additional,the failu res of tungsten alloy shells start at geometrical stress concentratio n zone in the all received shells,so o nly if the local stress concentratio n coefficients are markedly decreased by shell geometrical design,the tungsten alloy shells can be able to play an important role in several applications,including military engi-neering.
2002(6):432-436.
Abstract:
The rare earth films with switchable optical properties were found recen tly.During the hydrogen absorption/desorption procedure or electrochemical charging /discharging,the optical properties of the r are earth hydrides can be changed dra stically.In this paper,the crystal structure and thermodynamic properties of rare earth hydrides were intr oduced,the progress in the switchab le optical properties of rare earth hydride films was briefly reviewed.The mechanism for rare earth hydrides with switchable optical propertie s was discussed as well.
The rare earth films with switchable optical properties were found recen tly.During the hydrogen absorption/desorption procedure or electrochemical charging /discharging,the optical properties of the r are earth hydrides can be changed dra stically.In this paper,the crystal structure and thermodynamic properties of rare earth hydrides were intr oduced,the progress in the switchab le optical properties of rare earth hydride films was briefly reviewed.The mechanism for rare earth hydrides with switchable optical propertie s was discussed as well.
2002(6):437-439.
Abstract:
采用将Li2CO3,电解二氧化锰(EMD)和Co(NO3)2·6H2O混合进行高温固熔反应的合成方法,制备了1种尖晶石型金属氧化物催化材料LiMn2-xCoxO4。通过电化学测试(极化曲线、放电曲线)、X射线衍射分析(XRD)以及扫描电镜(SEM)等方法对电极的微观结构和性能进行了研究。实验结果表明,以LiMn1.95Co0.05O4为催化材料的气体扩散电极具有最好的综合电化学性能。其0.9V极化电位时的最大电流密度可达210mA/cm2AA型(5号)样品电池以100mA电流恒流放电,容量可高达4439mAh。
采用将Li2CO3,电解二氧化锰(EMD)和Co(NO3)2·6H2O混合进行高温固熔反应的合成方法,制备了1种尖晶石型金属氧化物催化材料LiMn2-xCoxO4。通过电化学测试(极化曲线、放电曲线)、X射线衍射分析(XRD)以及扫描电镜(SEM)等方法对电极的微观结构和性能进行了研究。实验结果表明,以LiMn1.95Co0.05O4为催化材料的气体扩散电极具有最好的综合电化学性能。其0.9V极化电位时的最大电流密度可达210mA/cm2AA型(5号)样品电池以100mA电流恒流放电,容量可高达4439mAh。
2002(6):440-444.
Abstract:
采用扫描电镜（SEM）、显微硬度分析、Ｘ－ray衍射和差热分析（ＤＴＡ）技术研究了Ｔi-46at%Al混合粉末机械合金化过程中的显微组织演变。结果表明：随着球磨过程的进行，Ｔi-46at%Al颗粒逐渐等轴化，粒度变小，粒度分布变窄；显微硬度增大，硬度分布和颗粒内成分逐渐均匀。经过６０h高能球磨，Ａl元素完全固溶入Ｔi晶格内，形成纳米Ｔi（Ａl）过饱和固溶体，同时，有非晶相形成；球磨至１００h，形成完全非晶相。非晶相的形成是界面处非平衡扩散的结果，在Ｔi-46at%Al合金中，机械合金化致非晶的晶粒条件是：晶粒尺寸≤１５nm。
采用扫描电镜（SEM）、显微硬度分析、Ｘ－ray衍射和差热分析（ＤＴＡ）技术研究了Ｔi-46at%Al混合粉末机械合金化过程中的显微组织演变。结果表明：随着球磨过程的进行，Ｔi-46at%Al颗粒逐渐等轴化，粒度变小，粒度分布变窄；显微硬度增大，硬度分布和颗粒内成分逐渐均匀。经过６０h高能球磨，Ａl元素完全固溶入Ｔi晶格内，形成纳米Ｔi（Ａl）过饱和固溶体，同时，有非晶相形成；球磨至１００h，形成完全非晶相。非晶相的形成是界面处非平衡扩散的结果，在Ｔi-46at%Al合金中，机械合金化致非晶的晶粒条件是：晶粒尺寸≤１５nm。
2002(6):445-448.
Abstract:
用薄试样push-out和push-back试验测试了SCS－6／Timetal 834复合材料从室温到530℃温度范围内的峰值载荷和滑动摩擦切应力。用轴对称圆柱有限元模型模拟计算了SiC纤维增强钛基复合材料不同温度下的界面应力沿轴向分布规律和界面脱粘过程。计算表明，push-out试验的界面脱粘过程可以用剪切强度准则描述，对于SCS－6／Timetal834复合材料。当界面单元尺寸L＝6.25μm时，其室温下界面剪切强度τm=500MPa,300℃时τm＝300MPa，530℃时τm＝140MPa。由于应力奇异性的影响，界面剪切强度的值与单元尺寸大小有关。
用薄试样push-out和push-back试验测试了SCS－6／Timetal 834复合材料从室温到530℃温度范围内的峰值载荷和滑动摩擦切应力。用轴对称圆柱有限元模型模拟计算了SiC纤维增强钛基复合材料不同温度下的界面应力沿轴向分布规律和界面脱粘过程。计算表明，push-out试验的界面脱粘过程可以用剪切强度准则描述，对于SCS－6／Timetal834复合材料。当界面单元尺寸L＝6.25μm时，其室温下界面剪切强度τm=500MPa,300℃时τm＝300MPa，530℃时τm＝140MPa。由于应力奇异性的影响，界面剪切强度的值与单元尺寸大小有关。
Xi Zhengpin
,
Zhang Jian
,
Wang Keguan g
,
Tang Xiande
,
Wu Quanxing
,
Yang Yanan
,
Bai Wenfeng
,
Wang Xin
2002(6):452-455.
Abstract:
The stainless steel fiber manufactu red by bundle drawing method has not o nly the high thermal resistance and c orrosion resistance,but also the flexility and weavable p roperties of textile fiber.It has been used widely as raw material for non woven fabrics and mixture fabrics.Through comparing the physical prop erties of stainless steel fiber with that of traditional woven fiber,it was regarded that stainless steel fib er and traditional textile fabric differ in density,elongation percentag e,rebound resilience,bending resistance,curliness and skin friction co-efficient ,which affect the quality of nonwoven fabrics woven by stainless steel fib er.So it' s important to investigate the properties of stainless steel fiber.
The stainless steel fiber manufactu red by bundle drawing method has not o nly the high thermal resistance and c orrosion resistance,but also the flexility and weavable p roperties of textile fiber.It has been used widely as raw material for non woven fabrics and mixture fabrics.Through comparing the physical prop erties of stainless steel fiber with that of traditional woven fiber,it was regarded that stainless steel fib er and traditional textile fabric differ in density,elongation percentag e,rebound resilience,bending resistance,curliness and skin friction co-efficient ,which affect the quality of nonwoven fabrics woven by stainless steel fib er.So it' s important to investigate the properties of stainless steel fiber.
2002(6):456-459.
Abstract:
AlN piezoelectric film has a lot of excellent physical chemistry properties.This discussion focus on the str uctural characters,pre-pared methods and applied prospect o f AlN piezoelectric films.
AlN piezoelectric film has a lot of excellent physical chemistry properties.This discussion focus on the str uctural characters,pre-pared methods and applied prospect o f AlN piezoelectric films.
2002(6):460-463.
Abstract:
Unreinforced 6066aluminium alloy a nd the alloy reinforced by SiC partic ulate with various volume fraction were fabricated by spray atomization and co -deposition,and also the unreinforced alloy was fabr icated by as -melten as a contrast,an d the materials were then extruded.It was observed that the aging respon ses of 6066Al and 6066Al /SiCp fabric ated by spray atomization and co -dep osition were accelerated.Metal-lography and transmission electron microscopy(TEM)were utilized to inspect the microstructures of the materials.The effect of processing route and the increased dislocation density resulted from the addition of SiC p articulate into metal matrix on the a ging behavior of the materials was di s-cussed.It is shown that the concentr ation of solute atomand kinetics of phase transformation in materials fa bricated by spray atomization and co-deposition are much higher than the o thers in this paper.Moreover,the decrease in grain size induced by spray atomization and co -deposition and the increased dislocation density in composites resulted from the ad dition of SiC particulates lead to su fficient positions for inhomogeneo ns nucleation and thus accelerate the k inetics of aging precipitation of th e materials involved in this study.
Unreinforced 6066aluminium alloy a nd the alloy reinforced by SiC partic ulate with various volume fraction were fabricated by spray atomization and co -deposition,and also the unreinforced alloy was fabr icated by as -melten as a contrast,an d the materials were then extruded.It was observed that the aging respon ses of 6066Al and 6066Al /SiCp fabric ated by spray atomization and co -dep osition were accelerated.Metal-lography and transmission electron microscopy(TEM)were utilized to inspect the microstructures of the materials.The effect of processing route and the increased dislocation density resulted from the addition of SiC p articulate into metal matrix on the a ging behavior of the materials was di s-cussed.It is shown that the concentr ation of solute atomand kinetics of phase transformation in materials fa bricated by spray atomization and co-deposition are much higher than the o thers in this paper.Moreover,the decrease in grain size induced by spray atomization and co -deposition and the increased dislocation density in composites resulted from the ad dition of SiC particulates lead to su fficient positions for inhomogeneo ns nucleation and thus accelerate the k inetics of aging precipitation of th e materials involved in this study.
2002(6):464-467.
Abstract:
利用高能球磨制备了含纳米晶Mg2Ni的Mg-Ni贮氢合金，并对其进行了吸氢反应研究。结果表明纳米晶Mg2Ni Mg Ni复相贮氢合金在100℃-150℃可和流动的氢气反应，证明了纳米晶的Mg2Ni不但自身具有很高的反应活性，而且对纳米晶的Mg也有较好的催化作用。
利用高能球磨制备了含纳米晶Mg2Ni的Mg-Ni贮氢合金，并对其进行了吸氢反应研究。结果表明纳米晶Mg2Ni Mg Ni复相贮氢合金在100℃-150℃可和流动的氢气反应，证明了纳米晶的Mg2Ni不但自身具有很高的反应活性，而且对纳米晶的Mg也有较好的催化作用。
2002(6):468-471.
Abstract:
The wear behavior of as cast and hot ex truded Al-Si-Pb alloys was investig ated under dry condition.The results show that the microstructure and mechanical prop erties can be greatly improved and porosity can be decreased significant ly by hot extrusion.These factors increase wear resistance of hot extr uded Al-Si-Pb obviously.Optical ob servation and X-ray photoelectron s pectroscopy(XPS)analysis reveal that the almost constant wear rate at mediate load level and better resistance to seizure for Al-Si-Pb alloys with more than 15%lead are due to a film of lubricant covered almost entire worn surface in the wear.This film is a mixture containing Al,Fe,S i,O and Pb.
The wear behavior of as cast and hot ex truded Al-Si-Pb alloys was investig ated under dry condition.The results show that the microstructure and mechanical prop erties can be greatly improved and porosity can be decreased significant ly by hot extrusion.These factors increase wear resistance of hot extr uded Al-Si-Pb obviously.Optical ob servation and X-ray photoelectron s pectroscopy(XPS)analysis reveal that the almost constant wear rate at mediate load level and better resistance to seizure for Al-Si-Pb alloys with more than 15%lead are due to a film of lubricant covered almost entire worn surface in the wear.This film is a mixture containing Al,Fe,S i,O and Pb.
2002(6):476-479.
Abstract:
采用压缩的方法对Ti75合金超塑变形时力学行为和组织演变进行了研究。结果表明,在800℃,5×10-4s-1以及850℃,1×10-1s-1的条件下,m值大于0.3,而900℃时,m值降低;在超塑变形初期由于动态再结晶和β相的扩散,实现板条组织的等轴化、细晶化、均匀化,使α晶粒得以进行滑动和转动,晶界运动成为主要变形机制;晶间β相对α晶粒的转动和滑动起着调节作用;而位错运动既是变形机制,又是晶界滑动的调节机制。
采用压缩的方法对Ti75合金超塑变形时力学行为和组织演变进行了研究。结果表明,在800℃,5×10-4s-1以及850℃,1×10-1s-1的条件下,m值大于0.3,而900℃时,m值降低;在超塑变形初期由于动态再结晶和β相的扩散,实现板条组织的等轴化、细晶化、均匀化,使α晶粒得以进行滑动和转动,晶界运动成为主要变形机制;晶间β相对α晶粒的转动和滑动起着调节作用;而位错运动既是变形机制,又是晶界滑动的调节机制。
2002(6):480-482.
Abstract:
通过大量实验，对不同Sr/Ba比制作的SBBT高压陶瓷电容器的击穿特性进行了研究，指出瓷体中的局部还原现象是造成电容器瓷片击穿场强严重下降的原因所在。经过理论分析，提出施主离子Bi^3 在固溶体中的不均匀分布导致瓷体还原的新观点。在此基础上，通过加入受主离子Mg^2 克服了还原现象，使电容器的击穿场强大幅度提高。
通过大量实验，对不同Sr/Ba比制作的SBBT高压陶瓷电容器的击穿特性进行了研究，指出瓷体中的局部还原现象是造成电容器瓷片击穿场强严重下降的原因所在。经过理论分析，提出施主离子Bi^3 在固溶体中的不均匀分布导致瓷体还原的新观点。在此基础上，通过加入受主离子Mg^2 克服了还原现象，使电容器的击穿场强大幅度提高。
