Volume 35,Issue 5,2006 Table of Contents
2006, 35(5):673-677.
Abstract:
Processing map is an effective tool for the optimization of materials workability, product property control and defect avoidance. Processing map is constructed by the superimposition of power dissipation efficiency and the instability maps, and can be divided into a safe domain and an unsafe domain. The developments of the Raj map and the processing map based on Dynamic Material Model (DMM) were reviewed in this paper. The DMM theory was introduced first, and then a comparison of different instability criteria were made to help to achieve a better control of microstructure during processing. Different deformation mechanisms, including dynamic recrystalli- zation, superplastic deformation, wedge cracking, formation of adiabatic shear bands and globulazation of lamella alpha were explained by the processing map based on DMM.
Processing map is an effective tool for the optimization of materials workability, product property control and defect avoidance. Processing map is constructed by the superimposition of power dissipation efficiency and the instability maps, and can be divided into a safe domain and an unsafe domain. The developments of the Raj map and the processing map based on Dynamic Material Model (DMM) were reviewed in this paper. The DMM theory was introduced first, and then a comparison of different instability criteria were made to help to achieve a better control of microstructure during processing. Different deformation mechanisms, including dynamic recrystalli- zation, superplastic deformation, wedge cracking, formation of adiabatic shear bands and globulazation of lamella alpha were explained by the processing map based on DMM.
2006, 35(5):678-681.
Abstract:
In this paper the development and study status of precision casting for the large-thin wall-complex titanium alloys casts are introduced in the aspects of melting, precision casting and defect detecting. The correlated casting technologies and numerical simulation processing are presented. Development trend of the large-thin wall complex titanium alloy castings by precision casting is described.
In this paper the development and study status of precision casting for the large-thin wall-complex titanium alloys casts are introduced in the aspects of melting, precision casting and defect detecting. The correlated casting technologies and numerical simulation processing are presented. Development trend of the large-thin wall complex titanium alloy castings by precision casting is described.
3 Phase Structure and Hydrogen Storage Properties of Ti_(17)Cr_(23)V_(55-)xZr_5Fe_x (x=11~16) Alloys
2006, 35(5):682-685.
Abstract:
系统研究了Ti17Cr23V55-xZr5Fex（x=11～16）合金的相结构以及储氢特性。XRD及SEM分析表明，所有合金的主相均为体心立方（bcc）结构的钒基固溶体，并含有σ-FeCr和Cr2Zr等第二相；随着Fe含量的增加，合金中的bcc主相含量和晶胞体积逐渐降低，σ-FeCr相含量逐渐增多，而Cr2Zr相含量几乎恒定。储氢性能测试表明，该系列合金的活化性能和动力学性能都很好，在20℃和4MPa初始氢压条件下首次吸氢即可活化，并且无需氢化孕育期就能快速吸氢。当Fe含量从x=11增加至x=16时，合金的室温最大吸氢量从268ml／g逐渐降低至25lml／g，80℃有效放氢量从153ml／g逐渐降低至137ml／g。研究表明，为了改善合金的有效储氢能力，必须消除合金中不吸氢的σ-FeCr相或者抑制σ-FeCr相的生成。
系统研究了Ti17Cr23V55-xZr5Fex（x=11～16）合金的相结构以及储氢特性。XRD及SEM分析表明，所有合金的主相均为体心立方（bcc）结构的钒基固溶体，并含有σ-FeCr和Cr2Zr等第二相；随着Fe含量的增加，合金中的bcc主相含量和晶胞体积逐渐降低，σ-FeCr相含量逐渐增多，而Cr2Zr相含量几乎恒定。储氢性能测试表明，该系列合金的活化性能和动力学性能都很好，在20℃和4MPa初始氢压条件下首次吸氢即可活化，并且无需氢化孕育期就能快速吸氢。当Fe含量从x=11增加至x=16时，合金的室温最大吸氢量从268ml／g逐渐降低至25lml／g，80℃有效放氢量从153ml／g逐渐降低至137ml／g。研究表明，为了改善合金的有效储氢能力，必须消除合金中不吸氢的σ-FeCr相或者抑制σ-FeCr相的生成。
2006, 35(5):686-689.
Abstract:
The hydrogen storage properties of V-Ti-Cr-Fe alloys with compositions of V(30 at%)-Ti(15 at%~55 at%)-Cr(7 at%~43 at%)- Fe(2 at%~18 at%) were studied in this paper. It is found that the hydrogen absorption capacities and the effective hydrogen capacities of the alloys are largely dependent on the Ti/(Cr+Fe) ratio. The alloy shows the largest effective hydrogen capacity at a Ti/(Cr+Fe) ratio of 1.0. With the increase of Ti/(Cr+Fe) ratio (0.9~1.05), the lattice parameters of the alloys and the enthalpy of hydrides grow, and the hydrogen desorbing plateau pressure declines. The alloy of V30Ti35Cr25Fe10 with 10at% Fe exhibits a hydrogen capacity of 3.6wt% and an effective hydrogen capacity of 2.0wt% at 298 K.
The hydrogen storage properties of V-Ti-Cr-Fe alloys with compositions of V(30 at%)-Ti(15 at%~55 at%)-Cr(7 at%~43 at%)- Fe(2 at%~18 at%) were studied in this paper. It is found that the hydrogen absorption capacities and the effective hydrogen capacities of the alloys are largely dependent on the Ti/(Cr+Fe) ratio. The alloy shows the largest effective hydrogen capacity at a Ti/(Cr+Fe) ratio of 1.0. With the increase of Ti/(Cr+Fe) ratio (0.9~1.05), the lattice parameters of the alloys and the enthalpy of hydrides grow, and the hydrogen desorbing plateau pressure declines. The alloy of V30Ti35Cr25Fe10 with 10at% Fe exhibits a hydrogen capacity of 3.6wt% and an effective hydrogen capacity of 2.0wt% at 298 K.
2006, 35(5):695-697.
Abstract:
研究了V-4Cr-4Ti合金的氧化动力学，采用XRD分析了在不同温度下，合金表层氧化物的形成过程。结果表明；V-4Cr-4Ti合金在300℃～400℃范围内，氧化速率很慢，氧化增重随时间的增加基本保持不变，在500℃～600℃化速率显著加快，其中600℃时的氧化增重是500℃时的10倍。表层氧化产物在400℃后逐渐形成，主要产物是V2O5。
研究了V-4Cr-4Ti合金的氧化动力学，采用XRD分析了在不同温度下，合金表层氧化物的形成过程。结果表明；V-4Cr-4Ti合金在300℃～400℃范围内，氧化速率很慢，氧化增重随时间的增加基本保持不变，在500℃～600℃化速率显著加快，其中600℃时的氧化增重是500℃时的10倍。表层氧化产物在400℃后逐渐形成，主要产物是V2O5。
2006, 35(5):698-702.
Abstract:
利用MEVVA源对Zr-4合金分别进行1×1016 ions/cm2至1×1017ions/cm2剂量的铈离子与铌离子注入,比较了Ce/Nb离子注入对Zr-4合金氧化行为的影响.结果表明,铈离子注入可以较大程度地提高Zr-4合金的抗氧化性能,而铌离子注入则在一定程度上使Zr-4合金的氧化性能下降.GAXRD分析显示,铈离子注入促进了氧化锆由单斜相向六方相的转变,但铌离子注入却对氧化锆相的转变没有影响.并探讨了Ce/Nb离子注入影响Zr-4合金氧化行为的机理.
利用MEVVA源对Zr-4合金分别进行1×1016 ions/cm2至1×1017ions/cm2剂量的铈离子与铌离子注入,比较了Ce/Nb离子注入对Zr-4合金氧化行为的影响.结果表明,铈离子注入可以较大程度地提高Zr-4合金的抗氧化性能,而铌离子注入则在一定程度上使Zr-4合金的氧化性能下降.GAXRD分析显示,铈离子注入促进了氧化锆由单斜相向六方相的转变,但铌离子注入却对氧化锆相的转变没有影响.并探讨了Ce/Nb离子注入影响Zr-4合金氧化行为的机理.
2006, 35(5):703-706.
Abstract:
Low cyclic fatigue behavior of Ti-1023 titanium alloy has been investigated under a fully reversed total strain-controlled mode. The strain-life and cyclic stress-strain data were analyzed to determine the individual strain fatigue parameters. It is found that the Ti-1023 alloy exhibited an initial slight cyclic hardening, followed by stable cycle at a total strain amplitude of 0.6%-0.8%, then cyclic softening at a total strain amplitude of above 0.8% to 3.0%. It is considered that the cyclic stress response behavior of Ti-1023 alloy depends on the total strain amplitude.
Low cyclic fatigue behavior of Ti-1023 titanium alloy has been investigated under a fully reversed total strain-controlled mode. The strain-life and cyclic stress-strain data were analyzed to determine the individual strain fatigue parameters. It is found that the Ti-1023 alloy exhibited an initial slight cyclic hardening, followed by stable cycle at a total strain amplitude of 0.6%-0.8%, then cyclic softening at a total strain amplitude of above 0.8% to 3.0%. It is considered that the cyclic stress response behavior of Ti-1023 alloy depends on the total strain amplitude.
2006, 35(5):707-710.
Abstract:
根据近临界钼当量和多元强化原则设计了一种新型亚稳β钛合金（Ti-B20），以室温拉伸性能和显微组织为主要考察内容研究了固溶处理对这种新合金时效响应的影响。结果表明：在同样的时效条件下，该合金的抗拉伸强度随着固溶温度的升高而升高，而固溶后水淬比空冷能产生更高的硬化效应，分析结果揭示了该合金独特的时效响应来自于其亚稳β相较低的稳定性和过剩空位对析出的共同作用。
根据近临界钼当量和多元强化原则设计了一种新型亚稳β钛合金（Ti-B20），以室温拉伸性能和显微组织为主要考察内容研究了固溶处理对这种新合金时效响应的影响。结果表明：在同样的时效条件下，该合金的抗拉伸强度随着固溶温度的升高而升高，而固溶后水淬比空冷能产生更高的硬化效应，分析结果揭示了该合金独特的时效响应来自于其亚稳β相较低的稳定性和过剩空位对析出的共同作用。
2006, 35(5):711-714.
Abstract:
研究了不同热处理工艺对一种镍基单晶高温合金的组织和持久性能的影响。结果表明：固溶处理时间越长，合金中的γ′相尺寸越均匀，有利于合金持久性能的提高。1080℃，4h和1150℃，4h时效后空冷获得的γ′相具有尺寸适合、立方度高的特点。2种时效处理对合金中温高应力的持久性能影响不明显，在高温低应力下，经1080℃时效处理的持久寿命略长。
研究了不同热处理工艺对一种镍基单晶高温合金的组织和持久性能的影响。结果表明：固溶处理时间越长，合金中的γ′相尺寸越均匀，有利于合金持久性能的提高。1080℃，4h和1150℃，4h时效后空冷获得的γ′相具有尺寸适合、立方度高的特点。2种时效处理对合金中温高应力的持久性能影响不明显，在高温低应力下，经1080℃时效处理的持久寿命略长。
2006, 35(5):719-723.
Abstract:
研究了NiAl-30．9Cr-3Mo-0．1Dy合金在1300K～1500K空气中的恒温氧化行为。结果表明：NiAl-30-9Cr-3Mo-0．1Dy合金的抗氧化性远优于NiAl-31Cr-3Mo合金：1500K的氧化动力学曲线基本遵循抛物线关系，在1350K～1450K的氧化动力学曲线符合立方抛物线关系，1300K的氧化动力学曲线则符合5次方关系。氧化过程中，合金的表面生成了连续致密的Al2O3氧化膜；稀土元素的活性作用以及Al2O3与基体合金之间的富Cr层的形成，提高了Al2O3的粘附能力。Dy的添加也减少了NiAl相上Al2O3的生成量，延缓了θ-Al2O3向α-Al2O3相的转变时间。
研究了NiAl-30．9Cr-3Mo-0．1Dy合金在1300K～1500K空气中的恒温氧化行为。结果表明：NiAl-30-9Cr-3Mo-0．1Dy合金的抗氧化性远优于NiAl-31Cr-3Mo合金：1500K的氧化动力学曲线基本遵循抛物线关系，在1350K～1450K的氧化动力学曲线符合立方抛物线关系，1300K的氧化动力学曲线则符合5次方关系。氧化过程中，合金的表面生成了连续致密的Al2O3氧化膜；稀土元素的活性作用以及Al2O3与基体合金之间的富Cr层的形成，提高了Al2O3的粘附能力。Dy的添加也减少了NiAl相上Al2O3的生成量，延缓了θ-Al2O3向α-Al2O3相的转变时间。
2006, 35(5):724-727.
Abstract:
Zr41.2Ti13.8Ni10Cu12.5Be22.5 bulk amorphous alloy was prepared by arc-melting and rapid casting into a copper mould. Hydrogen charging was performed electrochemically in glycerine-phosphoric acid electrolyte. The effects of hydrogen on the crystallization process of Zr-Ti-Cu-Ni-Be bulk amorphous alloy were studied by differential scanning calorimetry (DSC), Kissinger equation and high-resolution transmission electron microscope (HRTEM). It is shown that hydrogen increases the activation energy of the glass transition and crystallization, and retards the nucleation and crystal growth. Moreover, hydrogen charging contributes to the formation of isolated crystals, resulting in the precipitation of fine and uniformly distributed nanocrystallines.
Zr41.2Ti13.8Ni10Cu12.5Be22.5 bulk amorphous alloy was prepared by arc-melting and rapid casting into a copper mould. Hydrogen charging was performed electrochemically in glycerine-phosphoric acid electrolyte. The effects of hydrogen on the crystallization process of Zr-Ti-Cu-Ni-Be bulk amorphous alloy were studied by differential scanning calorimetry (DSC), Kissinger equation and high-resolution transmission electron microscope (HRTEM). It is shown that hydrogen increases the activation energy of the glass transition and crystallization, and retards the nucleation and crystal growth. Moreover, hydrogen charging contributes to the formation of isolated crystals, resulting in the precipitation of fine and uniformly distributed nanocrystallines.
2006, 35(5):728-731.
Abstract:
采用射流铸造法在水冷铜模中制备出成分为Zr52．5Cu30-xNi5．5Al12Nbx（x=0，3）的块体非晶合金。x=0时，样品为完全非晶结构；x=3时，试样的组织为非晶基体上均匀分布着尺度为20nm的富含Zr和Nb的成分偏聚区，同时富集区内镶嵌着尺寸为5nm左右bcc结构的Zr-Nb固溶体纳米颗粒。Zr52．5Cu27Ni55Al12Nb3合金的强度较具有完全非晶结构的Zr52.5Cu3027Ni55Al12合金有明显的提高：断裂强度由1600MPa增加到1964MPa。非晶基体上析出的纳米颗粒和成分偏聚增加了剪切变形的阻力。同时，基体变形由单滑移（x=0）转变为多滑移（x=3），并且滑移相互交错，避免了由于不均匀形夺诰成的据前脆断。提高了基体的强度。
采用射流铸造法在水冷铜模中制备出成分为Zr52．5Cu30-xNi5．5Al12Nbx（x=0，3）的块体非晶合金。x=0时，样品为完全非晶结构；x=3时，试样的组织为非晶基体上均匀分布着尺度为20nm的富含Zr和Nb的成分偏聚区，同时富集区内镶嵌着尺寸为5nm左右bcc结构的Zr-Nb固溶体纳米颗粒。Zr52．5Cu27Ni55Al12Nb3合金的强度较具有完全非晶结构的Zr52.5Cu3027Ni55Al12合金有明显的提高：断裂强度由1600MPa增加到1964MPa。非晶基体上析出的纳米颗粒和成分偏聚增加了剪切变形的阻力。同时，基体变形由单滑移（x=0）转变为多滑移（x=3），并且滑移相互交错，避免了由于不均匀形夺诰成的据前脆断。提高了基体的强度。
2006, 35(5):732-735.
Abstract:
The Ag-Ge alloy melts with deeply undercooled hypoeutectic, eutectic and hypereutectic were obtained via glass fluxing technique. The nucleation of the deeply undercooled alloy melts were triggered by atoms cluster sputtering on the surface of the melts. The atoms clusters were generated by an ion beam bombarding on the Cu foil fixed above the alloy melts. The resultant microstructure reveals that the induced atom clusters exert great influence on the microstructural evolution of the highly undercooled eutectic and hypereutectic Ag-Ge alloys, but no obvious influence on the highly undercooled hypoeutectic alloy. The microstructural evolution and formation mechanism were analyzed and discussed.
The Ag-Ge alloy melts with deeply undercooled hypoeutectic, eutectic and hypereutectic were obtained via glass fluxing technique. The nucleation of the deeply undercooled alloy melts were triggered by atoms cluster sputtering on the surface of the melts. The atoms clusters were generated by an ion beam bombarding on the Cu foil fixed above the alloy melts. The resultant microstructure reveals that the induced atom clusters exert great influence on the microstructural evolution of the highly undercooled eutectic and hypereutectic Ag-Ge alloys, but no obvious influence on the highly undercooled hypoeutectic alloy. The microstructural evolution and formation mechanism were analyzed and discussed.
2006, 35(5):736-739.
Abstract:
在电化学脱氧提纯金属钇的过程中，利用熔融的CaCl2使其副产品CaO的活度降低，脱去的氧以CO或CO2气体的形式从石墨阳极放出，只要电解条件合适，可使脱氧极限无限降低，同时金属钙是由CaCl2电解所得，较Ca—CaCl2熔盐脱氧提纯金属钇的方法，它降低了由于金属Ca的不纯而引入的杂质污染。对于形状规则的金属钇脱氧时间为t=（d^2／π^2D）ln[（4c0／nc）sinπx／d]。脱氧后的产品有少量的碳污染，但对实验进行一定的改进后，也可得到氧含量和碳含量都低于100μg/g的金属钇。
在电化学脱氧提纯金属钇的过程中，利用熔融的CaCl2使其副产品CaO的活度降低，脱去的氧以CO或CO2气体的形式从石墨阳极放出，只要电解条件合适，可使脱氧极限无限降低，同时金属钙是由CaCl2电解所得，较Ca—CaCl2熔盐脱氧提纯金属钇的方法，它降低了由于金属Ca的不纯而引入的杂质污染。对于形状规则的金属钇脱氧时间为t=（d^2／π^2D）ln[（4c0／nc）sinπx／d]。脱氧后的产品有少量的碳污染，但对实验进行一定的改进后，也可得到氧含量和碳含量都低于100μg/g的金属钇。
2006, 35(5):746-748.
Abstract:
通过XRD，SEM，EDX等手段研究了Zr对Sm2Fe17母合金及均匀化热处理后合金的相及微观结构的影响。结果表明：少量Zr元素的加入，能有效抑制铸锭中α-Fe相的生成：改变富Sm相的分布形态，使其在合金中沿基体Sm2Fe17相晶界呈网状分布，同时能部分取代基体Sm2Fe17相中Fe；短时的热处理能进一步降低合金中α-Fe含量在消除富Sm相，并使Zr在合金中的分布趋于均匀，而长时间热处理对加Zr合金不是一个必要的环节。因此，Zr元素的加入有效的降低了成本，有利于制备成分均一的高质量的Sm2Fe17相母合金。
通过XRD，SEM，EDX等手段研究了Zr对Sm2Fe17母合金及均匀化热处理后合金的相及微观结构的影响。结果表明：少量Zr元素的加入，能有效抑制铸锭中α-Fe相的生成：改变富Sm相的分布形态，使其在合金中沿基体Sm2Fe17相晶界呈网状分布，同时能部分取代基体Sm2Fe17相中Fe；短时的热处理能进一步降低合金中α-Fe含量在消除富Sm相，并使Zr在合金中的分布趋于均匀，而长时间热处理对加Zr合金不是一个必要的环节。因此，Zr元素的加入有效的降低了成本，有利于制备成分均一的高质量的Sm2Fe17相母合金。
2006, 35(5):749-751.
Abstract:
对成本较低、抗氧化性好的GdAl磁制冷工质材料制作工艺和性能进行了研究。比较了铸锭法和熔体快淬法对磁制冷工质材料组织结构和性能的影响。用直接测量法测其在外加磁场为1．2T，温度变化范围在-10℃～30℃下的磁热效应。结果表明：熔体快淬法制备的磁工质材料晶粒尺寸小于铸锭法，但其磁热效应和居里温度均低于铸锭样，原因是熔体快淬法制备的磁制冷工质材料中相结构发生变化，磁热效应优良的Gd3Al2相减少，性能较差的GdAl3相增加。同时，与铸锭组织相比，细晶组织内部出现大量的晶界，晶界处原子排列的无序度增加，材料的比热升高，导致磁热效应降低。再者，细晶晶界处的原子密度和配位数远远偏离了完整晶体的晶体结构，从而使配位数Z降低而导致居里温度降低。
对成本较低、抗氧化性好的GdAl磁制冷工质材料制作工艺和性能进行了研究。比较了铸锭法和熔体快淬法对磁制冷工质材料组织结构和性能的影响。用直接测量法测其在外加磁场为1．2T，温度变化范围在-10℃～30℃下的磁热效应。结果表明：熔体快淬法制备的磁工质材料晶粒尺寸小于铸锭法，但其磁热效应和居里温度均低于铸锭样，原因是熔体快淬法制备的磁制冷工质材料中相结构发生变化，磁热效应优良的Gd3Al2相减少，性能较差的GdAl3相增加。同时，与铸锭组织相比，细晶组织内部出现大量的晶界，晶界处原子排列的无序度增加，材料的比热升高，导致磁热效应降低。再者，细晶晶界处的原子密度和配位数远远偏离了完整晶体的晶体结构，从而使配位数Z降低而导致居里温度降低。
2006, 35(5):752-756.
Abstract:
采用差热分析（DTA）和热机械分析（TMA）技术以及光学显微镜和X射线衍射（XRD）研究了常规凝固和快速凝固条件下的AZ91D镁合金及其热挤压型材的相转变温度和线膨胀规律，探讨了其组织特征与热物性的关系。结果表明：常规凝固的AZ91D镁合金挤压前后在450℃左右均有明显的DTA峰，由于快速凝固薄带为单相过饱和α-Mg固溶体，热挤压过程中Al的脱溶而析出弥散分布的β-Mg17Al12相含量极少，因此快速凝固薄带及其热挤压的型材均无明显的DTA峰。AZ91D镁合金的线膨胀系数并非线性变化，在225℃前热挤压AZ91D镁合金型材的线膨胀系数波动幅度最低。热挤压后型材的热膨胀系数远小于铸态的热膨胀系数。
采用差热分析（DTA）和热机械分析（TMA）技术以及光学显微镜和X射线衍射（XRD）研究了常规凝固和快速凝固条件下的AZ91D镁合金及其热挤压型材的相转变温度和线膨胀规律，探讨了其组织特征与热物性的关系。结果表明：常规凝固的AZ91D镁合金挤压前后在450℃左右均有明显的DTA峰，由于快速凝固薄带为单相过饱和α-Mg固溶体，热挤压过程中Al的脱溶而析出弥散分布的β-Mg17Al12相含量极少，因此快速凝固薄带及其热挤压的型材均无明显的DTA峰。AZ91D镁合金的线膨胀系数并非线性变化，在225℃前热挤压AZ91D镁合金型材的线膨胀系数波动幅度最低。热挤压后型材的热膨胀系数远小于铸态的热膨胀系数。
2006, 35(5):757-760.
Abstract:
By analysis of impurity elements in HfO2 coating material, the influence of main impurity elements on the characteristic of coatings were studied. The results indicate that the metal elements and absorptive dielectric elements damage the HfO2 coatings. The more the Zr element content is, source center and form an the more the absorption is for the coatings in ultraviolet wave. The negative ion element will become the gas ejection in the process of evaporation of coating material, so decrease the damage threshold of the coatings.
By analysis of impurity elements in HfO2 coating material, the influence of main impurity elements on the characteristic of coatings were studied. The results indicate that the metal elements and absorptive dielectric elements damage the HfO2 coatings. The more the Zr element content is, source center and form an the more the absorption is for the coatings in ultraviolet wave. The negative ion element will become the gas ejection in the process of evaporation of coating material, so decrease the damage threshold of the coatings.
2006, 35(5):761-765.
Abstract:
Based on residual strength interference model and life interference model, a sensitivity analysis method on reliability was proposed for the fatigue crack growth life of powder metallurgy materials. The characteristics were considered on the multiple inclusions in the powder metallurgy materials, especially on the sensitivity analysis method. The relationship of sensitivity for the system failure probability was firstly constructed between multiple failure modes and single failure mode. The advanced method of first order and second moment was employed to calculate the partial derivatives of the system failure probability for the distribution parameters of the process variables and some basic variables. Then by use of regression analysis and numerical property of process variables, the sensitivities of parameters were derived for the process variables and basic variables. Finally, the sensitivities of system failure probability to the distribution parameters of the total basic variables were obtained. Then the proposed reliability sensitivity model was applied to a powder metallurgy turbine disk. The reliability sensitivity results show that the system failure probability of the turbine disk is significantly influenced by the crack growth coefficient c1 of Paris law at a given condition, and the essential relationship is clarified between the model and the distribution parameters. It is proved that the model might supply guidance to the design of powder metallurgy turbine disks. The calculated results were consistent each other with the residual strength interference model and the life interference model, and showed the feasibility of the proposed analysis method from the good agreement between the quantity calculation and the quality analysis.
Based on residual strength interference model and life interference model, a sensitivity analysis method on reliability was proposed for the fatigue crack growth life of powder metallurgy materials. The characteristics were considered on the multiple inclusions in the powder metallurgy materials, especially on the sensitivity analysis method. The relationship of sensitivity for the system failure probability was firstly constructed between multiple failure modes and single failure mode. The advanced method of first order and second moment was employed to calculate the partial derivatives of the system failure probability for the distribution parameters of the process variables and some basic variables. Then by use of regression analysis and numerical property of process variables, the sensitivities of parameters were derived for the process variables and basic variables. Finally, the sensitivities of system failure probability to the distribution parameters of the total basic variables were obtained. Then the proposed reliability sensitivity model was applied to a powder metallurgy turbine disk. The reliability sensitivity results show that the system failure probability of the turbine disk is significantly influenced by the crack growth coefficient c1 of Paris law at a given condition, and the essential relationship is clarified between the model and the distribution parameters. It is proved that the model might supply guidance to the design of powder metallurgy turbine disks. The calculated results were consistent each other with the residual strength interference model and the life interference model, and showed the feasibility of the proposed analysis method from the good agreement between the quantity calculation and the quality analysis.
2006, 35(5):766-769.
Abstract:
利用高温固相法合成了一种长余辉发光材料Gd2O2S：Ti，利用XRD测试了其结构并测试了其在紫外光激发下的发光特性；停止照射，有橙色的余辉，时间接近2h。分析该磷光体的发光和余辉产生细节，认为空穴和电子的复合导致Ti^3＋的^2E→^2T2的跃迁是产生发光和余辉的原因；并根据缺陷和空位对Gd2O2S：Ti的余辉机理进行探讨，提出了余辉机理模型。
利用高温固相法合成了一种长余辉发光材料Gd2O2S：Ti，利用XRD测试了其结构并测试了其在紫外光激发下的发光特性；停止照射，有橙色的余辉，时间接近2h。分析该磷光体的发光和余辉产生细节，认为空穴和电子的复合导致Ti^3＋的^2E→^2T2的跃迁是产生发光和余辉的原因；并根据缺陷和空位对Gd2O2S：Ti的余辉机理进行探讨，提出了余辉机理模型。
2006, 35(5):770-773.
Abstract:
In the present work, the low-load uniaxial and biaxial tensile testers were employed to carry out the uniaxial and biaxial tensions systemically for porous metal bodies at different uniaxial and biaxial tensile rates. The uniaxial tensile failure mechanism is analyzed, and the results show that the macroscopical failure behavior of the foam metals with open cells differ from either the transverse rupture by maximum tensile stress criterion, or the plastic flow failure by maximum shearing stress criterion, but behaves a complicated failure mode between these two criterions. In addition, the percentage elongation after fracture results mainly from the plastic deflexion of metallic struts within the three-dimensional reticulated structure, hardly from the plastic deformation of the metallic body under uniaxial tension. From the fracture morphologies under biaxial tension, it is found that the distribution of the stress field in the cruciform specimens of the foamed metal under biaxial equal-speed tension is similar to that under biaxial unequal-speed tension, and the maximum stress line of the stress field presents the four-fold symmetric curved-side tetragon.
In the present work, the low-load uniaxial and biaxial tensile testers were employed to carry out the uniaxial and biaxial tensions systemically for porous metal bodies at different uniaxial and biaxial tensile rates. The uniaxial tensile failure mechanism is analyzed, and the results show that the macroscopical failure behavior of the foam metals with open cells differ from either the transverse rupture by maximum tensile stress criterion, or the plastic flow failure by maximum shearing stress criterion, but behaves a complicated failure mode between these two criterions. In addition, the percentage elongation after fracture results mainly from the plastic deflexion of metallic struts within the three-dimensional reticulated structure, hardly from the plastic deformation of the metallic body under uniaxial tension. From the fracture morphologies under biaxial tension, it is found that the distribution of the stress field in the cruciform specimens of the foamed metal under biaxial equal-speed tension is similar to that under biaxial unequal-speed tension, and the maximum stress line of the stress field presents the four-fold symmetric curved-side tetragon.
2006, 35(5):774-778.
Abstract:
In this paper, 3 types of surface modes and 2 types of center modes and their practical applications were proposed and analyzed for the thermal stress analysis during quenching for no phase transformation alloy. And the 2D and 3D boundary and comer models without corner effect and their practical applications during quenching were also established and analyzed. The dynamic film effect, the phenomenon of dynamic wave of fathom line vs temperature, temperature gradient, thermal stresses and shape of plastic deformation zone were proposed. Also the thermal stress distribution, important to the technology, was analyzed with/without consideration of dynamic film effect. The relationship between the dynamic film effect and the comer effect during quenching was also analyzed.
In this paper, 3 types of surface modes and 2 types of center modes and their practical applications were proposed and analyzed for the thermal stress analysis during quenching for no phase transformation alloy. And the 2D and 3D boundary and comer models without corner effect and their practical applications during quenching were also established and analyzed. The dynamic film effect, the phenomenon of dynamic wave of fathom line vs temperature, temperature gradient, thermal stresses and shape of plastic deformation zone were proposed. Also the thermal stress distribution, important to the technology, was analyzed with/without consideration of dynamic film effect. The relationship between the dynamic film effect and the comer effect during quenching was also analyzed.
2006, 35(5):783-786.
Abstract:
研究了不同程度渗氢处理Zr-4合金的双轴循环变形行为。结果表明：当氢含量为CH=400μg/g时，在相同等效应变幅和相同相位角下，渗氢Zr-4合金的疲劳寿命高于原始冷变形状态Zr-4合金。当氢含量增加到CH=580μg/g时，渗氢处理Zr-4合金的双轴疲劳寿命却低于原始冷变形状态的Zr-4合金。透射电镜和金相显微镜观察表明，冷变形Zr-4合金渗氢后析出的氢化物具有良好的塑性变形能力，渗氢过程中中温条件下长时间保持导致基体产生去应力退火效应是Zr-4合金疲劳寿命提高的主要原因。
研究了不同程度渗氢处理Zr-4合金的双轴循环变形行为。结果表明：当氢含量为CH=400μg/g时，在相同等效应变幅和相同相位角下，渗氢Zr-4合金的疲劳寿命高于原始冷变形状态Zr-4合金。当氢含量增加到CH=580μg/g时，渗氢处理Zr-4合金的双轴疲劳寿命却低于原始冷变形状态的Zr-4合金。透射电镜和金相显微镜观察表明，冷变形Zr-4合金渗氢后析出的氢化物具有良好的塑性变形能力，渗氢过程中中温条件下长时间保持导致基体产生去应力退火效应是Zr-4合金疲劳寿命提高的主要原因。
2006, 35(5):791-794.
Abstract:
Ti-Al intermetallic composile with Al2O3 fiber interpenetration was fabricated in situ in slight-oxidizing atmosphere by the heat-treatment of the prefabricated pieces consisted of Ti, Al and other trace metallic elements. The final phases composition and mierostrueture were analyzed by XRD and SEM. The principle of the synthesis process and the influertce of the processing parameters on the mierostructure development were investigated in order to study whether the Al2O3 fiber would exist and what kind of matrix phases would be formed easily according to the molar ratio of components and the processing parameters.
Ti-Al intermetallic composile with Al2O3 fiber interpenetration was fabricated in situ in slight-oxidizing atmosphere by the heat-treatment of the prefabricated pieces consisted of Ti, Al and other trace metallic elements. The final phases composition and mierostrueture were analyzed by XRD and SEM. The principle of the synthesis process and the influertce of the processing parameters on the mierostructure development were investigated in order to study whether the Al2O3 fiber would exist and what kind of matrix phases would be formed easily according to the molar ratio of components and the processing parameters.
25 Microstructure and Mechanical Properties of Al-40Si Alloy Prepared by a Mixed Solid-Liquid Casting
2006, 35(5):795-797.
Abstract:
采用固液混合铸造的Al-40Si合金组织细小，合金力学性能明显优于传统铸造和半固态加工合金，并且解决了传统铸造Al-40Si合金铸件难以热加工的问题。在本工艺条件下，当添加平均粒度为120μm的粉末且粉末添加量与合金熔体质量比为1时，Al-40Si合金中的初晶硅平均粒度可控制在30μm以下；材料的室温力学性能为：σb=119.6MPa，σ0．2=105MPa，δ=1．43％。
采用固液混合铸造的Al-40Si合金组织细小，合金力学性能明显优于传统铸造和半固态加工合金，并且解决了传统铸造Al-40Si合金铸件难以热加工的问题。在本工艺条件下，当添加平均粒度为120μm的粉末且粉末添加量与合金熔体质量比为1时，Al-40Si合金中的初晶硅平均粒度可控制在30μm以下；材料的室温力学性能为：σb=119.6MPa，σ0．2=105MPa，δ=1．43％。
2006, 35(5):798-801.
Abstract:
借助于XRD，TG-DSC等技术研究了掺杂镧系金属对氢化燃烧合成镁镍储氢合金合成条件及合金性能的影响。结果表明：掺杂镧系金属的试样在氢气压力为2．0MPa，600℃下保温2h可大量形成Mg2NiH4；氢气压力越大，形成Mg2NiH4越多；过高的合成温度和过长的保温时间极不利于Mg2NiH4的形成；镧系金属的掺入使Mg2NiH4晶胞发生了一定的畸变；掺杂镧系金属的Mg2NiH4放氢温度为271．7℃左右，比未掺杂的降低了110℃左右；掺杂镧系金属试样的总放氢量可达3．21％（质量分数，下同）；掺杂镧系金属的试样在300℃，0．1MPa下的放氢时间为7min～8min；活化可适当提高吸放氢量。
借助于XRD，TG-DSC等技术研究了掺杂镧系金属对氢化燃烧合成镁镍储氢合金合成条件及合金性能的影响。结果表明：掺杂镧系金属的试样在氢气压力为2．0MPa，600℃下保温2h可大量形成Mg2NiH4；氢气压力越大，形成Mg2NiH4越多；过高的合成温度和过长的保温时间极不利于Mg2NiH4的形成；镧系金属的掺入使Mg2NiH4晶胞发生了一定的畸变；掺杂镧系金属的Mg2NiH4放氢温度为271．7℃左右，比未掺杂的降低了110℃左右；掺杂镧系金属试样的总放氢量可达3．21％（质量分数，下同）；掺杂镧系金属的试样在300℃，0．1MPa下的放氢时间为7min～8min；活化可适当提高吸放氢量。
2006, 35(5):802-805.
Abstract:
The dehydriding kinetics for MgH2 material synthesized by catalytic method under atmospheric pressure has been studied experimentally. A new kinetic model has been used to describe the curve tendency of the reacted fraction vs. time, to calculate the apparent activation energy of dehydriding reaction and to explain why this catalytic synthesis method can get a good kinetic result.
The dehydriding kinetics for MgH2 material synthesized by catalytic method under atmospheric pressure has been studied experimentally. A new kinetic model has been used to describe the curve tendency of the reacted fraction vs. time, to calculate the apparent activation energy of dehydriding reaction and to explain why this catalytic synthesis method can get a good kinetic result.
2006, 35(5):806-809.
Abstract:
利用微弧氧化技术在AZ31镁合金表面原位生长陶瓷层，用球-盘磨损实验机对试样的摩擦学性能进行了研究。结果表明：AZ31镁合金表面微弧氧化后可以形成均匀的表面陶瓷改性层，改性层由疏松层、致密层和截面层组成，厚约20μm。微弧氧化处理后的试样在干摩擦小滑动距离下表现出良好的耐磨性。并用SEM，XRD分析了微弧氧化陶瓷层的显微组织、表面形貌和相结构。
利用微弧氧化技术在AZ31镁合金表面原位生长陶瓷层，用球-盘磨损实验机对试样的摩擦学性能进行了研究。结果表明：AZ31镁合金表面微弧氧化后可以形成均匀的表面陶瓷改性层，改性层由疏松层、致密层和截面层组成，厚约20μm。微弧氧化处理后的试样在干摩擦小滑动距离下表现出良好的耐磨性。并用SEM，XRD分析了微弧氧化陶瓷层的显微组织、表面形貌和相结构。
2006, 35(5):810-813.
Abstract:
采用甘氨酸-硝酸盐燃烧法合成了中温固体氧化物燃料电池NiO-SDC复合阳极粉末。通过XRD和扫描电子显微镜对不同甘氨酸／金属离子摩尔比合成的复合粉末的结构和形貌进行了研究。XRD结果表明，直接燃烧合成的复合粉末除了NiO和CeO2的衍射峰外，还有Ni2O3衍射峰存在，粉末经900℃煅烧2h后Ni2O3峰消失，表明形成了NiO-SDC复合阳极粉末。氢气条件下的热重分析表明，复合粉末中NiO和SDC两相比例与溶液组分配比基本一致。制备的不同NiO含量薄膜阳极的电解质支撑单电池性能测试结果表明，阳极为60％NiO-SDC的单电池具有最高的开路电压。
采用甘氨酸-硝酸盐燃烧法合成了中温固体氧化物燃料电池NiO-SDC复合阳极粉末。通过XRD和扫描电子显微镜对不同甘氨酸／金属离子摩尔比合成的复合粉末的结构和形貌进行了研究。XRD结果表明，直接燃烧合成的复合粉末除了NiO和CeO2的衍射峰外，还有Ni2O3衍射峰存在，粉末经900℃煅烧2h后Ni2O3峰消失，表明形成了NiO-SDC复合阳极粉末。氢气条件下的热重分析表明，复合粉末中NiO和SDC两相比例与溶液组分配比基本一致。制备的不同NiO含量薄膜阳极的电解质支撑单电池性能测试结果表明，阳极为60％NiO-SDC的单电池具有最高的开路电压。
2006, 35(5):814-816.
Abstract:
Silver copper oxide composites were prepared by reactive synthesis and powder metallurgy methods, Microstructures and properties of silver copper oxide composites by the two methods were studied in the present paper. The results show that silver copper oxide fabricated by reactive synthesis possess unique ringed microstructure that brings its good mechanical and alternating current contact properties. It means that reactive synthesis method can obtain better mechanic properties than powder metallurgy method in fabrication silver copper oxide composites. The service life of Ag/CuO material with reactive synthesis was twice as long as it with powder metallurgy under AC (220 V) and DC (24 V).
Silver copper oxide composites were prepared by reactive synthesis and powder metallurgy methods, Microstructures and properties of silver copper oxide composites by the two methods were studied in the present paper. The results show that silver copper oxide fabricated by reactive synthesis possess unique ringed microstructure that brings its good mechanical and alternating current contact properties. It means that reactive synthesis method can obtain better mechanic properties than powder metallurgy method in fabrication silver copper oxide composites. The service life of Ag/CuO material with reactive synthesis was twice as long as it with powder metallurgy under AC (220 V) and DC (24 V).
2006, 35(5):817-819.
Abstract:
采用化学镀法在镍粉表面包覆一层金属银，然后将这种包覆粉进行真空热处理，即可制得具有抗氧化作用的微米级镍-银双金属粉末。用SEM、XRD、粒度分析和热重分析表征不同包覆厚度的双金属粉和原始镍粉的表面形貌、包覆结构及其抗氧化性。结果表明：镍粉表面包覆的银越多，双金属粉形状越规则，表面包覆层越致密，双金属粉的抗氧化温度也就越高，颗粒表面银含量为76％（质量分数，下同）时，其抗氧化温度可以达到850℃。
采用化学镀法在镍粉表面包覆一层金属银，然后将这种包覆粉进行真空热处理，即可制得具有抗氧化作用的微米级镍-银双金属粉末。用SEM、XRD、粒度分析和热重分析表征不同包覆厚度的双金属粉和原始镍粉的表面形貌、包覆结构及其抗氧化性。结果表明：镍粉表面包覆的银越多，双金属粉形状越规则，表面包覆层越致密，双金属粉的抗氧化温度也就越高，颗粒表面银含量为76％（质量分数，下同）时，其抗氧化温度可以达到850℃。
2006, 35(5):820-823.
Abstract:
利用脉冲激光沉积(PLD)技术,在Si(100)衬底上制得了导电氧化铱(IrO2)薄膜.讨论了沉积参数(O2分压、衬底温度)对IrO2薄膜的结构、表面形貌和导电性的影响.结果表明20 Pa为最佳O2分压、400℃～500℃为适宜的沉积温度,此条件下制得的IrO2薄膜结晶完整,组织均匀、形状一致,排列致密,其最低电阻率约为42μΩ·cm.
利用脉冲激光沉积(PLD)技术,在Si(100)衬底上制得了导电氧化铱(IrO2)薄膜.讨论了沉积参数(O2分压、衬底温度)对IrO2薄膜的结构、表面形貌和导电性的影响.结果表明20 Pa为最佳O2分压、400℃～500℃为适宜的沉积温度,此条件下制得的IrO2薄膜结晶完整,组织均匀、形状一致,排列致密,其最低电阻率约为42μΩ·cm.
2006, 35(5):824-827.
Abstract:
用工业型脉冲直流等离子体化学气相沉积（PCVD）设备，在高速钢（W18Cr4V）基材表面沉积新型四元Ti-Si-C-N复合超硬薄膜。结果表明：Ti-Si-C-N薄膜是由面心立方结构的TiN和TiC纳米晶、Ti（C，N）固溶体及存在于晶界的非晶Si3N4和α-C组成，形成TiN／TiC／Ti（C，N）／α-C／α-Si3N,复相结构，这种复相结构存在着[111]，[220]和[200]混合择优取向。SiCl4和CH4流量变化是影响薄膜相组成和硬度变化的主要工艺参数。随Si含量的增加，薄膜的显微硬度先升后降，表面形貌由致密的细颗粒状变为粗大的枝条状；C元素的加入能抑制柱状晶的形成，对硬度影响较小。
用工业型脉冲直流等离子体化学气相沉积（PCVD）设备，在高速钢（W18Cr4V）基材表面沉积新型四元Ti-Si-C-N复合超硬薄膜。结果表明：Ti-Si-C-N薄膜是由面心立方结构的TiN和TiC纳米晶、Ti（C，N）固溶体及存在于晶界的非晶Si3N4和α-C组成，形成TiN／TiC／Ti（C，N）／α-C／α-Si3N,复相结构，这种复相结构存在着[111]，[220]和[200]混合择优取向。SiCl4和CH4流量变化是影响薄膜相组成和硬度变化的主要工艺参数。随Si含量的增加，薄膜的显微硬度先升后降，表面形貌由致密的细颗粒状变为粗大的枝条状；C元素的加入能抑制柱状晶的形成，对硬度影响较小。
2006, 35(5):828-831.
Abstract:
TiO2 thin films pre-coated with CuO can induce the formation of their rutile type structure. The pre-coating process was completed through the deposit of TiO2 sol-gel onto a glass substrate smeared with a layer of Cu(CH3COO)2 solution. The photocatalysis activity of the TiO2 thin films obtained was improved significantly. When a Cu(CH3COO)2 solution of 1(wt)% was used in the so-called pre-coated process, the activity of formed thin films reached their maximum, 53% higher than the untreated TiO2 thin films. Experimental results reveal that the greater the deformation of TiO2 lattice and the more the rutile type structure in the thin films, the higher the photocatalysis activity the thin films possess. SEM shows that the particle size of TiO2 films pre-coated with CuO is finer than that of the original films. XPS analysis demonstrates the Ti3+ content in the TiO2 thin films increases also when pre-coated with CuO.
TiO2 thin films pre-coated with CuO can induce the formation of their rutile type structure. The pre-coating process was completed through the deposit of TiO2 sol-gel onto a glass substrate smeared with a layer of Cu(CH3COO)2 solution. The photocatalysis activity of the TiO2 thin films obtained was improved significantly. When a Cu(CH3COO)2 solution of 1(wt)% was used in the so-called pre-coated process, the activity of formed thin films reached their maximum, 53% higher than the untreated TiO2 thin films. Experimental results reveal that the greater the deformation of TiO2 lattice and the more the rutile type structure in the thin films, the higher the photocatalysis activity the thin films possess. SEM shows that the particle size of TiO2 films pre-coated with CuO is finer than that of the original films. XPS analysis demonstrates the Ti3+ content in the TiO2 thin films increases also when pre-coated with CuO.
2006, 35(5):832-835.
Abstract:
Highly preferred orientation TiB2 coatings were obtained by electrochemical techniques of continuous current plating (CCP) and pulse current plating (PCP) in fluoride-chloride electrolytes (KF-KCl) containing K2TiF6 and KBF4 as the electrochemically-active components. The effects of cathode current density on the crystal size, preferred orientation, micro stresses and lattice constants were studied by X-ray diffraction (XRD). The results indicate that the crystal size gets smaller with the increase of the cathode current density due to the increase of the nucleation rate at the over-potential. Compared with the CCP, the crystal size of TiB2 coatings prepared by PIC is finer because PIC can weaken the concentration polarization and increase the nucleation rate by increasing the ion concentration of diffusion layer. The preferred orientation of TiB2 coatings prepared above is (001) plane at the experimental conditions, which can be well explained by the two-dimension crystal nuclei theory. The lattice constant of TiB2 coatings deviates from the theoretical value due to the stress in coatings. Besides, it is confirmed that the binding between TiB2 coatings and graphite substrates is the physical binding from the results of thermodynamic predictions, XRD and EDS (Energy Dispersive X-ray Spectrum). The existence of some cracks at the interface may be attributed to the difference between the thermal expansion coefficients of TiB2 and graphite.
Highly preferred orientation TiB2 coatings were obtained by electrochemical techniques of continuous current plating (CCP) and pulse current plating (PCP) in fluoride-chloride electrolytes (KF-KCl) containing K2TiF6 and KBF4 as the electrochemically-active components. The effects of cathode current density on the crystal size, preferred orientation, micro stresses and lattice constants were studied by X-ray diffraction (XRD). The results indicate that the crystal size gets smaller with the increase of the cathode current density due to the increase of the nucleation rate at the over-potential. Compared with the CCP, the crystal size of TiB2 coatings prepared by PIC is finer because PIC can weaken the concentration polarization and increase the nucleation rate by increasing the ion concentration of diffusion layer. The preferred orientation of TiB2 coatings prepared above is (001) plane at the experimental conditions, which can be well explained by the two-dimension crystal nuclei theory. The lattice constant of TiB2 coatings deviates from the theoretical value due to the stress in coatings. Besides, it is confirmed that the binding between TiB2 coatings and graphite substrates is the physical binding from the results of thermodynamic predictions, XRD and EDS (Energy Dispersive X-ray Spectrum). The existence of some cracks at the interface may be attributed to the difference between the thermal expansion coefficients of TiB2 and graphite.
2006, 35(5):836-840.
Abstract:
以从废旧锂离子电池中回收的钴锂为原料,Na2CO3为沉淀剂,聚乙二醇为分散剂,用共沉淀法制备了LiCoO2粉体.用DSC-TG对前躯体进行了差热分析.结果表明在煅烧过程中有3次明显的失重,650℃以后失重曲线趋于平直.用XRD对LiCoO2进行了晶相分析,在750℃制备的LiCoO2晶格常数为a=2.810 13×10-10m,c=14.034 6×10-10m,c/a=4.994 29,接近于标准LiCoO2的晶格常数.用BET分析了LiCoO2的粉体比表面积,其值为18.55 m2/g,并通过SEM观察到平均颗粒半径为70 nm左右,属于纳米级粉体.首次充电容量达146 mA/hg,放电容量达142 mAh/g,10次循环后仍保持96%的放电比容量.
以从废旧锂离子电池中回收的钴锂为原料,Na2CO3为沉淀剂,聚乙二醇为分散剂,用共沉淀法制备了LiCoO2粉体.用DSC-TG对前躯体进行了差热分析.结果表明在煅烧过程中有3次明显的失重,650℃以后失重曲线趋于平直.用XRD对LiCoO2进行了晶相分析,在750℃制备的LiCoO2晶格常数为a=2.810 13×10-10m,c=14.034 6×10-10m,c/a=4.994 29,接近于标准LiCoO2的晶格常数.用BET分析了LiCoO2的粉体比表面积,其值为18.55 m2/g,并通过SEM观察到平均颗粒半径为70 nm左右,属于纳米级粉体.首次充电容量达146 mA/hg,放电容量达142 mAh/g,10次循环后仍保持96%的放电比容量.
