Volume 0,Issue 5,2001 Table of Contents
2001(5):321-325.
Abstract:
The current status of bulge experiments for testing mechanical properties of thin film is outlined in this article. Stressed is the status of the mechanical model and the manufacture of specimens used in the test, including their advantages and disadvantages. Moreover, the possible prospects of this test are overviewed.
The current status of bulge experiments for testing mechanical properties of thin film is outlined in this article. Stressed is the status of the mechanical model and the manufacture of specimens used in the test, including their advantages and disadvantages. Moreover, the possible prospects of this test are overviewed.
2001(5):326-330.
Abstract:
The Molecular Dynamics Method with the Finnis Sinclair many body potential is used to calculate the formation energies and combination energies of some small vacancy clusters with different configurations in TiAl. The most stable configuration of a vacancy cluster and its effect on vacancy migration nearby the cluster are simulated and discussed. The results show that, in the most stable configuration, each vacancy makes its best endeavor to form nearest neighbor relationship with the other vacancies, and there are anti site defect nearby the cluster. The atoms nearby the vacancy cluster would move towards the cluster center for bigger cluster, and it seems that there exist interstitials in the vacancy cluster. The existing vacancy cluster as the aggregation center of vacancy has the ability of trapping or absorbing the near vacancy.
The Molecular Dynamics Method with the Finnis Sinclair many body potential is used to calculate the formation energies and combination energies of some small vacancy clusters with different configurations in TiAl. The most stable configuration of a vacancy cluster and its effect on vacancy migration nearby the cluster are simulated and discussed. The results show that, in the most stable configuration, each vacancy makes its best endeavor to form nearest neighbor relationship with the other vacancies, and there are anti site defect nearby the cluster. The atoms nearby the vacancy cluster would move towards the cluster center for bigger cluster, and it seems that there exist interstitials in the vacancy cluster. The existing vacancy cluster as the aggregation center of vacancy has the ability of trapping or absorbing the near vacancy.
2001(5):331-334.
Abstract:
In this paper, specific emphasis has been placed on exploring the effect of electric field treatment on grain boundary strengthening for Al Li alloy 2090+Ce. The relation of the tensile properties to the electric field was investigated. The results show that the grain boundary can be so strengthened as to weaken the intergranular failure. An improvement in ductility has been obtained, however, the change of strength was very little. The research results of phenomenological theory show that the solution ability of solute atoms was enhanced and the cluster gather of solute atoms and vacancy was improved by electricfield treatment.
In this paper, specific emphasis has been placed on exploring the effect of electric field treatment on grain boundary strengthening for Al Li alloy 2090+Ce. The relation of the tensile properties to the electric field was investigated. The results show that the grain boundary can be so strengthened as to weaken the intergranular failure. An improvement in ductility has been obtained, however, the change of strength was very little. The research results of phenomenological theory show that the solution ability of solute atoms was enhanced and the cluster gather of solute atoms and vacancy was improved by electricfield treatment.
2001(5):335-338.
Abstract:
利用多向大变形锻造工业工艺和显微组织观察，研究了工业7075铝合金中细晶粒显微组织的演变。在工业生产条件下，7075铝合金基体在锻造过程中可发生完全的动态再结晶，产生出平均尺寸小于2μm的细小等轴再结晶晶粒结构，晶粒内包含高密度位错与弥散细小的第二相粒子缠结。锻件经390℃～450℃退火1h后，晶粒尺寸仍在2μm～3μm左右，这说明动态再结晶晶粒结构在静态退火期间是很稳定的。
利用多向大变形锻造工业工艺和显微组织观察，研究了工业7075铝合金中细晶粒显微组织的演变。在工业生产条件下，7075铝合金基体在锻造过程中可发生完全的动态再结晶，产生出平均尺寸小于2μm的细小等轴再结晶晶粒结构，晶粒内包含高密度位错与弥散细小的第二相粒子缠结。锻件经390℃～450℃退火1h后，晶粒尺寸仍在2μm～3μm左右，这说明动态再结晶晶粒结构在静态退火期间是很稳定的。
2001(5):339-341.
Abstract:
Cu/Mo/Cu(CMC)laminate is a new kind of composite with highl electrical conductivity and thermal conductivity. Especially, the CTE(coefficient of thermal expansion) of the laminate can be tailored by changing the cladding ratio, so a significant amount of CMC sheet is used in electronic industry for substrates of integrated circuits. At present, it is an ideal material to replace the pure molybdenum sheet. In this study, CMC laminate was produced with explosive cladding technique. The interface's morphology and microstructure were observed by means of OM. SEM. Microhardness measurements revealed the feature of deformation zone.
Cu/Mo/Cu(CMC)laminate is a new kind of composite with highl electrical conductivity and thermal conductivity. Especially, the CTE(coefficient of thermal expansion) of the laminate can be tailored by changing the cladding ratio, so a significant amount of CMC sheet is used in electronic industry for substrates of integrated circuits. At present, it is an ideal material to replace the pure molybdenum sheet. In this study, CMC laminate was produced with explosive cladding technique. The interface's morphology and microstructure were observed by means of OM. SEM. Microhardness measurements revealed the feature of deformation zone.
2001(5):342-345.
Abstract:
利用TEM技术及体视分析原理，研究2090铝锂合金和2090＋Ce稀土高强铝锂合金（Ce添加量为0．05％）中位错组态、δ'相体积分数随时效条件的变化，并利用微观力学原理分析和计算δ'相的强化机制及强化贡献。研究目的在于探讨δ'相的强化作用随时效条件的变化以及微量稀土Ce的添加对δ'相强化贡献的影响。研究结果表明：时效初期，Ce的添加对δ'相的沉淀一定的抑制作用；理论计算结果表明，δ'相的强化贡献约为30MPa-60MPa，2090＋Ce合金中δ'相的强化贡献略低于同等时效条件的2090合金。
利用TEM技术及体视分析原理，研究2090铝锂合金和2090＋Ce稀土高强铝锂合金（Ce添加量为0．05％）中位错组态、δ'相体积分数随时效条件的变化，并利用微观力学原理分析和计算δ'相的强化机制及强化贡献。研究目的在于探讨δ'相的强化作用随时效条件的变化以及微量稀土Ce的添加对δ'相强化贡献的影响。研究结果表明：时效初期，Ce的添加对δ'相的沉淀一定的抑制作用；理论计算结果表明，δ'相的强化贡献约为30MPa-60MPa，2090＋Ce合金中δ'相的强化贡献略低于同等时效条件的2090合金。
2001(5):349-352.
Abstract:
在Co-Al-Ti三元系中，设计并熔炼了一系列含Co(Al,Ti)/(Co)的多相合金，试图通过在脆性的B2型金属间化合物Co(Al,Ti)中引入塑性的初级固溶体（Co）来提高材料的室温塑性。通过对合金铸态和经过简单热处理态的分析，确定了Co(Al,Ti)/(Co)两相区的成分范围、相平衡和相结构状况；并通过室温压缩实验了解了合金的变形行为，对合金的进一步开发前景作出了评估。
在Co-Al-Ti三元系中，设计并熔炼了一系列含Co(Al,Ti)/(Co)的多相合金，试图通过在脆性的B2型金属间化合物Co(Al,Ti)中引入塑性的初级固溶体（Co）来提高材料的室温塑性。通过对合金铸态和经过简单热处理态的分析，确定了Co(Al,Ti)/(Co)两相区的成分范围、相平衡和相结构状况；并通过室温压缩实验了解了合金的变形行为，对合金的进一步开发前景作出了评估。
2001(5):353-356.
Abstract:
开发了一对以AB2型Ti系多元合金为热端合金、以AB5型稀土系多元合金为冷端合金的车用氢化物空调新型贮氢合金对。在操作温度为200℃／40℃/20℃的条件下，合金对的理论COPc为0．41。针对汽车尾气热容小的特点，提出了热端反应器采用多种具有不同性能的贮氢合金组成复合氢化物床的新设想，可使汽车发动机尾气废热得到充分利用。并用所研制的3对合金对组成复合氢化物床计算得出空调系统COPc为0．46。
开发了一对以AB2型Ti系多元合金为热端合金、以AB5型稀土系多元合金为冷端合金的车用氢化物空调新型贮氢合金对。在操作温度为200℃／40℃/20℃的条件下，合金对的理论COPc为0．41。针对汽车尾气热容小的特点，提出了热端反应器采用多种具有不同性能的贮氢合金组成复合氢化物床的新设想，可使汽车发动机尾气废热得到充分利用。并用所研制的3对合金对组成复合氢化物床计算得出空调系统COPc为0．46。
2001(5):357-360.
Abstract:
Diamond like carbon coatings with different thickness have been prepared on Ti alloy substrate by rf plasma enhanced chemical vapor deposition (rf PECVD), their surface morphology and mechanical properties were analyzed and evaluated by AFM, nanoindentation, scratch test, friction test and fretting wear test. The results show that: with the increasing of coating thickness, the surface roughness sharply increases, then significant decreases, at last tending to stable; the hardness and bond strength increase with thickness, but the friction coefficient decreases; and the friction coefficient of DLC coatings against corundum obtained by fretting test decreases with the increase of relative humidity to be below 0 1 in an aqueous condition. All of that are beneficial to their biomedical applications in body fluids.
Diamond like carbon coatings with different thickness have been prepared on Ti alloy substrate by rf plasma enhanced chemical vapor deposition (rf PECVD), their surface morphology and mechanical properties were analyzed and evaluated by AFM, nanoindentation, scratch test, friction test and fretting wear test. The results show that: with the increasing of coating thickness, the surface roughness sharply increases, then significant decreases, at last tending to stable; the hardness and bond strength increase with thickness, but the friction coefficient decreases; and the friction coefficient of DLC coatings against corundum obtained by fretting test decreases with the increase of relative humidity to be below 0 1 in an aqueous condition. All of that are beneficial to their biomedical applications in body fluids.
2001(5):361-364.
Abstract:
Three kinds of interactions between the twins and the anti phase boundaries(APBs) have been studied in massive transformation for Ti 47Al 2Nb 1Mn alloys. The results show that: the twins are usually thicker when the twins intersect with the APBs or the APBs are terminated with the twins; and the twins usually thinner when the twins are terminated with the APBs on the ends.In the late case, the twin has a wedge shape and ended at the APB with a sharp tip. Thus, we can conclude that in the course of the massive transformation there must be some close relations between the twins and the APBs which lead to the three kinds of interactions mentioned above.
Three kinds of interactions between the twins and the anti phase boundaries(APBs) have been studied in massive transformation for Ti 47Al 2Nb 1Mn alloys. The results show that: the twins are usually thicker when the twins intersect with the APBs or the APBs are terminated with the twins; and the twins usually thinner when the twins are terminated with the APBs on the ends.In the late case, the twin has a wedge shape and ended at the APB with a sharp tip. Thus, we can conclude that in the course of the massive transformation there must be some close relations between the twins and the APBs which lead to the three kinds of interactions mentioned above.
2001(5):365-368.
Abstract:
The substructure, fracture morphology and residual stress of shot peened commercial pure titanium were analyzed by the methods of TEM, SEM and XRD. The structure, stress and roughness affecting the fatigue strength were studied in this paper. The results show that twinning plays an important role in plastic deformation of hcp metals, the shot peening layer consists of twins and deformation bands, and the twin interactions can cause micro damage. Fatigue would relax the residual stresses and decrease the strengthening effect. The increased surface roughness has negative effects.
The substructure, fracture morphology and residual stress of shot peened commercial pure titanium were analyzed by the methods of TEM, SEM and XRD. The structure, stress and roughness affecting the fatigue strength were studied in this paper. The results show that twinning plays an important role in plastic deformation of hcp metals, the shot peening layer consists of twins and deformation bands, and the twin interactions can cause micro damage. Fatigue would relax the residual stresses and decrease the strengthening effect. The increased surface roughness has negative effects.
2001(5):369-371.
Abstract:
The distortion behavior and distortion controlling processes of PIM tungsten based heavy alloys were studied in this paper. Liquid phase sintering distorts the samples due to the large difference in density between W phase and liquid phase. The two step sintering process can effectively decrease the distortion of the alloys with higher tungsten contents. For the alloy with low tungsten contents, the powder mixture can decrease the sintering temperature of the alloy for full densification with good mechanical properties.
The distortion behavior and distortion controlling processes of PIM tungsten based heavy alloys were studied in this paper. Liquid phase sintering distorts the samples due to the large difference in density between W phase and liquid phase. The two step sintering process can effectively decrease the distortion of the alloys with higher tungsten contents. For the alloy with low tungsten contents, the powder mixture can decrease the sintering temperature of the alloy for full densification with good mechanical properties.
2001(5):372-375.
Abstract:
Powder metallurgy and hot pressed technology were adopted to manufacture the TiNb fiber reinforced TiAl matrix composites. The bending strength as well as the fracture toughness of the material were investigated. Results show that the TiNb/TiAl composite has a better property than the matrix, and the bending strength in the laboratory corresponds to the forecast of the mixture rule very well. Furthermore, the interface of the composite is consisted of full lamella structure, the matrix and fibers combine well, and the damaging ratio of the fibers is little due to the manufacture technology. It is showed that the PM technology is a good method to manufacture the TiAl matrix composite.
Powder metallurgy and hot pressed technology were adopted to manufacture the TiNb fiber reinforced TiAl matrix composites. The bending strength as well as the fracture toughness of the material were investigated. Results show that the TiNb/TiAl composite has a better property than the matrix, and the bending strength in the laboratory corresponds to the forecast of the mixture rule very well. Furthermore, the interface of the composite is consisted of full lamella structure, the matrix and fibers combine well, and the damaging ratio of the fibers is little due to the manufacture technology. It is showed that the PM technology is a good method to manufacture the TiAl matrix composite.
2001(5):376-379.
Abstract:
考察了表面涂有ZnCl2-KCl盐膜的纯Ni和M38G，GH864两种Ni基合金在450℃纯氧气氛中的耐蚀性。结果表明：3种材料均发生了加速性腐蚀，形成的表面产物膜十分疏松并与基体的粘附性较差；合金中较高的Cr含量并没有提供良好的保护性，其腐蚀速度高于纯Ni。分析了NiO与Cr2O3氧化膜在该环境中具有不同热力学稳定性的原因，并讨论了材料的加速腐蚀机理。
考察了表面涂有ZnCl2-KCl盐膜的纯Ni和M38G，GH864两种Ni基合金在450℃纯氧气氛中的耐蚀性。结果表明：3种材料均发生了加速性腐蚀，形成的表面产物膜十分疏松并与基体的粘附性较差；合金中较高的Cr含量并没有提供良好的保护性，其腐蚀速度高于纯Ni。分析了NiO与Cr2O3氧化膜在该环境中具有不同热力学稳定性的原因，并讨论了材料的加速腐蚀机理。
2001(5):380-383.
Abstract:
通过合金电极电化学容量与粘结剂的类型、导电剂的用量、电极粉末颗粒尺寸的关系，讨论了制极制备工艺对储氢合金M1(NiCoSiMnAl)5电化学性能的影响。结果表明：选择6％－9％的PVA溶液作为粘结剂，合金电极可获得满意的充放电性能；采用粒度范围较宽的合金粉制作电极，有利于增加合金粉末的填充密度，提高储氢合金的利用率；导电剂用量对电极性能的影响显著。
通过合金电极电化学容量与粘结剂的类型、导电剂的用量、电极粉末颗粒尺寸的关系，讨论了制极制备工艺对储氢合金M1(NiCoSiMnAl)5电化学性能的影响。结果表明：选择6％－9％的PVA溶液作为粘结剂，合金电极可获得满意的充放电性能；采用粒度范围较宽的合金粉制作电极，有利于增加合金粉末的填充密度，提高储氢合金的利用率；导电剂用量对电极性能的影响显著。
2001(5):384-387.
Abstract:
用水热法合成了具有良好结晶度和大层间距的α－磷酸钛晶体（记为α-TiP），并用SRD，HREM，IR及TG／DSC等方法对其进行了表征。得到的晶体形貌规整并具有较高的热稳定性。本实验对水热法合成α－磷酸钛的实验条件进行了系统研究，给出了优化的合成条件。研究表明，当反应体系的磷酸浓度为5M－10M时在180℃下反应6h即可获得良好的α－TiP晶体。
用水热法合成了具有良好结晶度和大层间距的α－磷酸钛晶体（记为α-TiP），并用SRD，HREM，IR及TG／DSC等方法对其进行了表征。得到的晶体形貌规整并具有较高的热稳定性。本实验对水热法合成α－磷酸钛的实验条件进行了系统研究，给出了优化的合成条件。研究表明，当反应体系的磷酸浓度为5M－10M时在180℃下反应6h即可获得良好的α－TiP晶体。
2001(5):388-391.
Abstract:
The effects of the post heat treatment for electroplating on the adhesion of Ni or Ni/Cu coating were mainly studied in this thesis. The XRD results showed that the diffusion layer was formed between the coating and the base metal after the diffusion treatment, which was mainly consisted of solid solusion or intermetallic compound, such as Ni 3Ti, NiTi and NiTi 2 There was no direct relationship between the improvement of plating adhesion and the thickness of diffusion layer due to the formation of metallic bonds between the coating and the base metal. The metallic bonds can be easily formed and the plating adhesion can be improved when the integrality of the nonmetallic film, such as oxide film, was destroyed by the solid sulusion and metallic compound in thc diffusion layer. The microcosmic clearance between the plating layer and matrix did not increase due to the heat treatment
The effects of the post heat treatment for electroplating on the adhesion of Ni or Ni/Cu coating were mainly studied in this thesis. The XRD results showed that the diffusion layer was formed between the coating and the base metal after the diffusion treatment, which was mainly consisted of solid solusion or intermetallic compound, such as Ni 3Ti, NiTi and NiTi 2 There was no direct relationship between the improvement of plating adhesion and the thickness of diffusion layer due to the formation of metallic bonds between the coating and the base metal. The metallic bonds can be easily formed and the plating adhesion can be improved when the integrality of the nonmetallic film, such as oxide film, was destroyed by the solid sulusion and metallic compound in thc diffusion layer. The microcosmic clearance between the plating layer and matrix did not increase due to the heat treatment
18 Advances in the Reserach of Surface Pretreatment of Cemented Carbide Substrate for Diamond Coationg
2001(5):392-395.
Abstract:
The poor adhesivity between diamond coating and cemented carbide substrate due to is the big difference in properties of diamond and cemented carbides, especially in the presence of Co in the substrate, which has the deleterious effect and brings about the transformation of diamond to amorphous and graphitic carbon. How to improve the adhesivity is very important for the products development of carbides with diamond film. The adhesivity can be improved by strictly controlling the process of diamond depostion, but the surface pretreatmetn of cemented carbide substrate is another more important approach to improve the adhesivity. The main factors effecting the adhesivity are briefly introduced, and the recent advances in the research of surface pretreatment of cemented carbide substrate for diamond coating are reviewed.
The poor adhesivity between diamond coating and cemented carbide substrate due to is the big difference in properties of diamond and cemented carbides, especially in the presence of Co in the substrate, which has the deleterious effect and brings about the transformation of diamond to amorphous and graphitic carbon. How to improve the adhesivity is very important for the products development of carbides with diamond film. The adhesivity can be improved by strictly controlling the process of diamond depostion, but the surface pretreatmetn of cemented carbide substrate is another more important approach to improve the adhesivity. The main factors effecting the adhesivity are briefly introduced, and the recent advances in the research of surface pretreatment of cemented carbide substrate for diamond coating are reviewed.
2001(5):396-399.
Abstract:
介绍了在AlN烧结中，烧结助剂的各类和加入量对AlN陶瓷材料的烧结致密度和热传导系数的影响。通过分析不同烧结助剂对AlN低温烧结（＜1600℃)的影响，认为有效的烧结助剂应该满足以下4个原则：①和AlN颗粒表面Al2O3反应生成的化合物的液化温度应该低于1600℃；②在烧结过程中不要诱发AlN的分解和氧化；③应该能以晶界析出Al2O3化合物的形式降低AlN晶格中的氧；④形成的Al2O3化合物应该有不亚于AlN的导热性，或者该化合物在晶界的含量要足够低。由于单一的烧结助剂无法同时满足以上4个条件，Y2O3－CaO-Li2O复合烧结助剂，极有希望成为高性能的AlN低温烧结的有效助剂。
介绍了在AlN烧结中，烧结助剂的各类和加入量对AlN陶瓷材料的烧结致密度和热传导系数的影响。通过分析不同烧结助剂对AlN低温烧结（＜1600℃)的影响，认为有效的烧结助剂应该满足以下4个原则：①和AlN颗粒表面Al2O3反应生成的化合物的液化温度应该低于1600℃；②在烧结过程中不要诱发AlN的分解和氧化；③应该能以晶界析出Al2O3化合物的形式降低AlN晶格中的氧；④形成的Al2O3化合物应该有不亚于AlN的导热性，或者该化合物在晶界的含量要足够低。由于单一的烧结助剂无法同时满足以上4个条件，Y2O3－CaO-Li2O复合烧结助剂，极有希望成为高性能的AlN低温烧结的有效助剂。
