Volume 0,Issue 6,2001 Table of Contents
2001(6):401-405.
Abstract:
Important Tungsten alloys include W Ni Fe, W Ni Cu, W Cu, and WC Co. In the 21th century, nanograin tungsten alloys will emerge as new materials with muctiple functions and ultrahigh properties. Nanograin bulk tungsten alloys prepared from nanocrystalline powders will exhibit superior physical and mechanical properties, and have potential advantages in microelectronic applications, such as, heat sinks, electronic packages, and anti armor applications. This paper reviews the current research on nanograin refractory tungsten alloy composite powders, introduces numerous technique for nanometer tungsten alloy powder preparation, and points out research directions of nanometer refractory tungsten alloy materials.
Important Tungsten alloys include W Ni Fe, W Ni Cu, W Cu, and WC Co. In the 21th century, nanograin tungsten alloys will emerge as new materials with muctiple functions and ultrahigh properties. Nanograin bulk tungsten alloys prepared from nanocrystalline powders will exhibit superior physical and mechanical properties, and have potential advantages in microelectronic applications, such as, heat sinks, electronic packages, and anti armor applications. This paper reviews the current research on nanograin refractory tungsten alloy composite powders, introduces numerous technique for nanometer tungsten alloy powder preparation, and points out research directions of nanometer refractory tungsten alloy materials.
2001(6):406-412.
Abstract:
The double shear specimen was designed for the study of the creep behavior of nickel base single crystal superalloys at high temperature. The creep stress and strain distributions and the influence of boundary conditions for the specimen are studied in the present paper. The results show that a preliminary analysis, by using the finite element code ABAQUS and RIGID SURFACE as a boundary condition for loading is conservative because a homogeneous state of shear stress is maintained only up to shear strains of the order of 10%. Using a more realistic boundary condition for loading (ABAQUS option: CONTACT PAIR), the homogeneous state of shear stress in the double shear specimen is maintained throughout creep up to much higher shear strains than that of the originally estimated. A macrorelationship has been built between the material creep properties (Norton law) and the macrobehavior of the double shear behavior, so that the material creep properties can be derived from the creep experiments of double shear specimens, and corresponding equations have been presented. Therefore, the further work on crystallographic anisotropic finite element creep stress analysis of our double shear creep specimen will be based on the more realistic loading condition which is represented by the ABAQUS option CONTACT PAIR A good agreement has been obtained between the creep behavior of the double shear damage specimen of the experiment and finite element analysis on nickel base single crystal superalloys.
The double shear specimen was designed for the study of the creep behavior of nickel base single crystal superalloys at high temperature. The creep stress and strain distributions and the influence of boundary conditions for the specimen are studied in the present paper. The results show that a preliminary analysis, by using the finite element code ABAQUS and RIGID SURFACE as a boundary condition for loading is conservative because a homogeneous state of shear stress is maintained only up to shear strains of the order of 10%. Using a more realistic boundary condition for loading (ABAQUS option: CONTACT PAIR), the homogeneous state of shear stress in the double shear specimen is maintained throughout creep up to much higher shear strains than that of the originally estimated. A macrorelationship has been built between the material creep properties (Norton law) and the macrobehavior of the double shear behavior, so that the material creep properties can be derived from the creep experiments of double shear specimens, and corresponding equations have been presented. Therefore, the further work on crystallographic anisotropic finite element creep stress analysis of our double shear creep specimen will be based on the more realistic loading condition which is represented by the ABAQUS option CONTACT PAIR A good agreement has been obtained between the creep behavior of the double shear damage specimen of the experiment and finite element analysis on nickel base single crystal superalloys.
2001(6):413-417.
Abstract:
研究了Ti-40(Ti-25V-15Cr-0.2Si)阻燃钛合金中的第二相及其对合金性能的影响。研究结果表明：固溶温度升高，Ti40合金析出第二相的趋势增大；低于850℃固溶，合金中没有第二相析出，高于850℃固溶，合金中析出棒状α相和少量Ti5Si3相；910℃固溶＋600℃时效，合金存在第二相有α和Ti5Si3相；860℃固溶＋600℃时效，合金仅存在Ti5Si3相，固溶时效态存在的第二相对合金的性能没有明显影响，540℃，100h热暴露，合金中存在的各种形态的α相和Ti5Si3析出物，明显降低合金的热稳定性能。
研究了Ti-40(Ti-25V-15Cr-0.2Si)阻燃钛合金中的第二相及其对合金性能的影响。研究结果表明：固溶温度升高，Ti40合金析出第二相的趋势增大；低于850℃固溶，合金中没有第二相析出，高于850℃固溶，合金中析出棒状α相和少量Ti5Si3相；910℃固溶＋600℃时效，合金存在第二相有α和Ti5Si3相；860℃固溶＋600℃时效，合金仅存在Ti5Si3相，固溶时效态存在的第二相对合金的性能没有明显影响，540℃，100h热暴露，合金中存在的各种形态的α相和Ti5Si3析出物，明显降低合金的热稳定性能。
Li Shuangming
,
Hao Qitang
,
Li Jinshan\+
,
Kou Hongchao\+
,
Fu Hengzhi\+
,
Jia Jun\+
,
Guo Jingjie\+
2001(6):418-421.
Abstract:
Using one frequency field to inductively heat the solid metal and another frequency field to confine the molten metal to a near net shape without contacting with the mold, a dual frequency eletromagnetic shaping process of liquid metal has been successfully realized by high supersonic and two high frequency electromagnetic fields. Owing to the fact that induction heating and electromagnetic shaping for different frequency fields can be adjusted separately, the control of the high supersonic dual frequency electromagnetic shaping of liquid metal is easier not only than single frequency electromagnetic shaping, but also than dual high frequency electromagnetic shaping. By designing suitable induction heating and electromagnetic shaping coils, some near net shaped sample parts with elliptical and menisoid cross sections have been produced using high supersonic dual frequency electromagnetic shaping process.
Using one frequency field to inductively heat the solid metal and another frequency field to confine the molten metal to a near net shape without contacting with the mold, a dual frequency eletromagnetic shaping process of liquid metal has been successfully realized by high supersonic and two high frequency electromagnetic fields. Owing to the fact that induction heating and electromagnetic shaping for different frequency fields can be adjusted separately, the control of the high supersonic dual frequency electromagnetic shaping of liquid metal is easier not only than single frequency electromagnetic shaping, but also than dual high frequency electromagnetic shaping. By designing suitable induction heating and electromagnetic shaping coils, some near net shaped sample parts with elliptical and menisoid cross sections have been produced using high supersonic dual frequency electromagnetic shaping process.
2001(6):422-427.
Abstract:
Metal matrix composite (MMC) surface layer have been formed on 6061 aluminium alloy surface by laser cladding of using a 2kW continuous wave (CW) Nd YAG laser. The TiC particle reinforced Al Ti composite coating was prepared by in situ contact reaction with preplaced powder mixtures of Ti and SiC. The formation mechanism of TiC particles has been studied. It was found that composite coating consisting of TiC particles dispersed in coating matrix could be obtained using the correct ratio of Ti to SiC powders and a laser power density. Compound material cladding coating mainly consists of Ti Al intermetallic compound and Al supersaturated solid solution. The coating was characterized by good metallurgical bonding between the coating and the substrate, good wettability between the reinforcement TiC and the coating matrix,and a fine grain structure. The results show that the composite coating greatly enhances the surface hardness.
Metal matrix composite (MMC) surface layer have been formed on 6061 aluminium alloy surface by laser cladding of using a 2kW continuous wave (CW) Nd YAG laser. The TiC particle reinforced Al Ti composite coating was prepared by in situ contact reaction with preplaced powder mixtures of Ti and SiC. The formation mechanism of TiC particles has been studied. It was found that composite coating consisting of TiC particles dispersed in coating matrix could be obtained using the correct ratio of Ti to SiC powders and a laser power density. Compound material cladding coating mainly consists of Ti Al intermetallic compound and Al supersaturated solid solution. The coating was characterized by good metallurgical bonding between the coating and the substrate, good wettability between the reinforcement TiC and the coating matrix,and a fine grain structure. The results show that the composite coating greatly enhances the surface hardness.
2001(6):428-432.
Abstract:
By the response curved surface technique (First, in line with actually chosen response curved surface regression and then in terms of the corresponding coefficient estimated by the least square method),it is possible to get the initial response curved surface regression equation. Based on the magnitude of the significance inspection value, the less significant variable of the coefficient can be eliminated by the lease square estimation ,the final curved surfac equation is established. In this paper, the response curved regression is chosen for making up for the deficiency of the orthogonal experiments in the research of the nanometer size TiO 2/UPR(Unsaturated Polyester Resins) composite. The results show that the response curved surface regression analysis technique is a good mathematics analysis method in the materials research.
By the response curved surface technique (First, in line with actually chosen response curved surface regression and then in terms of the corresponding coefficient estimated by the least square method),it is possible to get the initial response curved surface regression equation. Based on the magnitude of the significance inspection value, the less significant variable of the coefficient can be eliminated by the lease square estimation ,the final curved surfac equation is established. In this paper, the response curved regression is chosen for making up for the deficiency of the orthogonal experiments in the research of the nanometer size TiO 2/UPR(Unsaturated Polyester Resins) composite. The results show that the response curved surface regression analysis technique is a good mathematics analysis method in the materials research.
2001(6):433-436.
Abstract:
The influence of pH value on corrosion behavior of N ion implanted SUS316L stainless steel, Co Cr alloy, CPTi and Ti 6Al 4V alloy surgery medical materials has been investigated in Hank's solution using electrochemical technology. Experimental results indicate that corrosion potentials of specimens decline, and E b and crevice corrosion potentials of SUS316L stainless steel and Co Cr alloy also decline with decreasing pH value, which results in an increase of the sensibility of local corrosion. The corrosion rates of CPTi and Ti 6Al 4V alloy also increase in Hank's solution with much lower pH value.
The influence of pH value on corrosion behavior of N ion implanted SUS316L stainless steel, Co Cr alloy, CPTi and Ti 6Al 4V alloy surgery medical materials has been investigated in Hank's solution using electrochemical technology. Experimental results indicate that corrosion potentials of specimens decline, and E b and crevice corrosion potentials of SUS316L stainless steel and Co Cr alloy also decline with decreasing pH value, which results in an increase of the sensibility of local corrosion. The corrosion rates of CPTi and Ti 6Al 4V alloy also increase in Hank's solution with much lower pH value.
2001(6):437-439.
Abstract:
The microstructure, mechanical properties, the mechanisms of strengthening and toughening for the 10%C f/SiO 2 composite prepared by vacuum hot pressing, were studied. The SiO 2 glass matrix crystallized partially after hot pressing. The composite has a lamellar structure with the carbon fibers in parallel with the hot pressing plane. The bending strength, fracture toughness and fracture strain of the composite are significantly improved, compared with that of the matrix. Bridging and pulling out of carbon fibers and crabon fibers and crack deflection induced by the carbon fibers are the principal mechanisms of strengthening and toughening.
The microstructure, mechanical properties, the mechanisms of strengthening and toughening for the 10%C f/SiO 2 composite prepared by vacuum hot pressing, were studied. The SiO 2 glass matrix crystallized partially after hot pressing. The composite has a lamellar structure with the carbon fibers in parallel with the hot pressing plane. The bending strength, fracture toughness and fracture strain of the composite are significantly improved, compared with that of the matrix. Bridging and pulling out of carbon fibers and crabon fibers and crack deflection induced by the carbon fibers are the principal mechanisms of strengthening and toughening.
2001(6):440-443.
Abstract:
Heteroepitaxial diamond films were grown on Si(100) via electron emission with a bias voltage, by using microwave plasma CVD and hot filament CVD. The piezoresistivity and magnetoresistivity of p type diamond films obtained by the cold implantation and rapid annealing have been investigated.The experimental results show that epitaxial diamond films have pronounced piezoresistivity and magnetoresistivity effect and can still be operated under extreme conditions such as high temperature, heavy radiation and a strong chemical corrosive environment
Heteroepitaxial diamond films were grown on Si(100) via electron emission with a bias voltage, by using microwave plasma CVD and hot filament CVD. The piezoresistivity and magnetoresistivity of p type diamond films obtained by the cold implantation and rapid annealing have been investigated.The experimental results show that epitaxial diamond films have pronounced piezoresistivity and magnetoresistivity effect and can still be operated under extreme conditions such as high temperature, heavy radiation and a strong chemical corrosive environment
2001(6):444-447.
Abstract:
Ti3Al基的Ti-24A1-14Nb-3V-0.5Mo(at%)合金为非理想的超塑材料.用超塑压缩方法研究了合金的超塑变形行为,分析了变形量和应变速率对流变应力及组织演变的影响.结果表明所研究合金的最佳超塑变形温度为980 ℃.在980 ℃,2×10-3s-1的条件下,应变速率敏感性指数值为0.55.应变速率对合金超塑压缩时的力学行为和组织演变有显著的影响.
Ti3Al基的Ti-24A1-14Nb-3V-0.5Mo(at%)合金为非理想的超塑材料.用超塑压缩方法研究了合金的超塑变形行为,分析了变形量和应变速率对流变应力及组织演变的影响.结果表明所研究合金的最佳超塑变形温度为980 ℃.在980 ℃,2×10-3s-1的条件下,应变速率敏感性指数值为0.55.应变速率对合金超塑压缩时的力学行为和组织演变有显著的影响.
2001(6):448-452.
Abstract:
The microstructures of ZrC particle reinforced tungsten matrix composite (ZrC P/W, 30vol%ZrC particles) have been investigated using XRD, SEM and TEM. The experimental results indicate that the ZrC particles inhabit the growth of tungsten grains during sintering. The relative density of the composite is less than that of monolithic tungsten. W atoms diffuse in the lattice of ZrC, resulting in a formation of (Zr, W)C solid solution in ZrC particles, and a little of Zr diffuse in W lattice, resulting in a metallurgical bonding of ZrC particles to W matrix. W 2C and ZrO 2 phases were found rarely in the composites. At room temperature, the fracture toughness, elastic modulus and hardness of the composite increase because of the additive ZrC particles, but the flexural strength of the composite is lower than that of monolithic tungsten. The toughening mechanisms of ZrC P/W composite are crack deflection and grain refining.
The microstructures of ZrC particle reinforced tungsten matrix composite (ZrC P/W, 30vol%ZrC particles) have been investigated using XRD, SEM and TEM. The experimental results indicate that the ZrC particles inhabit the growth of tungsten grains during sintering. The relative density of the composite is less than that of monolithic tungsten. W atoms diffuse in the lattice of ZrC, resulting in a formation of (Zr, W)C solid solution in ZrC particles, and a little of Zr diffuse in W lattice, resulting in a metallurgical bonding of ZrC particles to W matrix. W 2C and ZrO 2 phases were found rarely in the composites. At room temperature, the fracture toughness, elastic modulus and hardness of the composite increase because of the additive ZrC particles, but the flexural strength of the composite is lower than that of monolithic tungsten. The toughening mechanisms of ZrC P/W composite are crack deflection and grain refining.
12 Effect of Phase Composition of Tungsten Oxide on Homogeneity of Reduced Ultrafine Tungsten Powder
2001(6):453-456.
Abstract:
The effect of phase composition of tungsten oxide on the homogeneity of ultrafine tungsten powder has been studied using a conventional hydrogen reduction technique. The results show that ultrafine and homogeneous tungsten powder can be produced from single phase tungsten oxide. The tungsten powder made by multi phase oxides may be fine , but not homogenous due to differences between the reduction rates (or redution paths) of various oxides.
The effect of phase composition of tungsten oxide on the homogeneity of ultrafine tungsten powder has been studied using a conventional hydrogen reduction technique. The results show that ultrafine and homogeneous tungsten powder can be produced from single phase tungsten oxide. The tungsten powder made by multi phase oxides may be fine , but not homogenous due to differences between the reduction rates (or redution paths) of various oxides.
Du Jihong
,
Xi Zhengping
,
Ju He
,
Zhang Xiaolian
,
Cai Tianxiao
,
Zhang Yuping
,
Wu Hongrang
,
Lai Huasheng
2001(6):457-459.
Abstract:
针对稀土金属钕熔盐电解过程中存在的一系列问题 ,研制了一种新型的坩埚材料。该材料是以 Nd2 O3为基分别添加不同氧化物的陶瓷材料 ,它是通过粉末烧结法制备并进行了电解实验。结果表明 :该材料有较好的耐蚀性 ,陶瓷材料的腐蚀率小于 2× 10 - 2 g/ cm2 .h。工业实验条件下 ,材料的腐蚀率为 6 .5× 10 - 2 g/ cm2 .h
针对稀土金属钕熔盐电解过程中存在的一系列问题 ,研制了一种新型的坩埚材料。该材料是以 Nd2 O3为基分别添加不同氧化物的陶瓷材料 ,它是通过粉末烧结法制备并进行了电解实验。结果表明 :该材料有较好的耐蚀性 ,陶瓷材料的腐蚀率小于 2× 10 - 2 g/ cm2 .h。工业实验条件下 ,材料的腐蚀率为 6 .5× 10 - 2 g/ cm2 .h
2001(6):460-462.
Abstract:
A technology of Au thick film by ion plating have been worked out according to the investigation of the transition coating of Au thick film by ion plating. The technology consists of several steps including ionic cleaning of sample surface, plating of Ni Cu transition coating and heat treatment in the chamber etc. All steps can be realized by once charging. The results of test run show that number of reciprocating movement of the friction surfaces reached 120 times at the speed of 2.5 m/s, which meet requirement completely.
A technology of Au thick film by ion plating have been worked out according to the investigation of the transition coating of Au thick film by ion plating. The technology consists of several steps including ionic cleaning of sample surface, plating of Ni Cu transition coating and heat treatment in the chamber etc. All steps can be realized by once charging. The results of test run show that number of reciprocating movement of the friction surfaces reached 120 times at the speed of 2.5 m/s, which meet requirement completely.
2001(6):463-466.
Abstract:
The effects of strain and alloy composition on some important properties of 316L stainless steel fibre are discussed in this paper. The experimental results show that alloying element content influence the austenitic stability of stainless steel. The lower the element content, the poorer the austenitic stability. The main reason for adjusting the alloy content of stainless steel fibre is to inhibit unstable austenite transformation into martensite under strain.
The effects of strain and alloy composition on some important properties of 316L stainless steel fibre are discussed in this paper. The experimental results show that alloying element content influence the austenitic stability of stainless steel. The lower the element content, the poorer the austenitic stability. The main reason for adjusting the alloy content of stainless steel fibre is to inhibit unstable austenite transformation into martensite under strain.
2001(6):467-470.
Abstract:
针对电动车用大型动力Ni/MH电池工作温度较高的特点，系统地研究了3种工作温度（25℃，40℃和60℃）对贮氢合金RENi3.55Mn0.4Co0.75Al0.3电化学性能的影响。研究结果表明，RENi3.55Mn0.4Co0.75Al0.3合金具有单一的CaCu5型LaNi5相结构，当工作温度从25℃提高至60℃时，合金的放氢平衡压力从0．04MPa升高至0．13MPa，同时放氢平台的宽度变窄，倾斜度增大，从而导致该合金的放氢量降低；随着温度的升高，合金的活化性能得到显著改善，但合金的最大放电容量和循环稳定性明显降低；而中高温（40℃和60℃）时合金的高倍率放电性能则明显优于室温（25℃）时的高倍率放电性能。
针对电动车用大型动力Ni/MH电池工作温度较高的特点，系统地研究了3种工作温度（25℃，40℃和60℃）对贮氢合金RENi3.55Mn0.4Co0.75Al0.3电化学性能的影响。研究结果表明，RENi3.55Mn0.4Co0.75Al0.3合金具有单一的CaCu5型LaNi5相结构，当工作温度从25℃提高至60℃时，合金的放氢平衡压力从0．04MPa升高至0．13MPa，同时放氢平台的宽度变窄，倾斜度增大，从而导致该合金的放氢量降低；随着温度的升高，合金的活化性能得到显著改善，但合金的最大放电容量和循环稳定性明显降低；而中高温（40℃和60℃）时合金的高倍率放电性能则明显优于室温（25℃）时的高倍率放电性能。
2001(6):471-474.
Abstract:
The effect of current density on electroplating titanium in molten NaCl KCl was studied, and a comparison made of the different between the effects of direct current and pulse current in molten salt electroplating. The new technique of pulse current molten salt electroplating and its improvement of e the diffusion limited process was studied. A good Ti coating has been obtained on the surface of metal substrate.
The effect of current density on electroplating titanium in molten NaCl KCl was studied, and a comparison made of the different between the effects of direct current and pulse current in molten salt electroplating. The new technique of pulse current molten salt electroplating and its improvement of e the diffusion limited process was studied. A good Ti coating has been obtained on the surface of metal substrate.
2001(6):475-477.
Abstract:
采用 H1Cr2 6 Ni2 1作为过渡层焊丝 ,焊接 Monel40 0 / 16 Mn R复合板。研究了复合板焊接接头的弯曲性能、拉伸强度、主要化学元素在焊缝中的扩散程度及其微观组织。结果表明 ,焊缝成形良好 ,在距复层焊缝表面 2 .4mm范围内 ,焊丝化学成份对复层焊缝化学成份的稀释率为 0。焊接接头的拉伸强度为 6 30 MPa。面弯角大于等于 12 0°,背弯角为 180°,侧弯角大于等于 10 0°。焊接接头具有良好的综合机械性能。
采用 H1Cr2 6 Ni2 1作为过渡层焊丝 ,焊接 Monel40 0 / 16 Mn R复合板。研究了复合板焊接接头的弯曲性能、拉伸强度、主要化学元素在焊缝中的扩散程度及其微观组织。结果表明 ,焊缝成形良好 ,在距复层焊缝表面 2 .4mm范围内 ,焊丝化学成份对复层焊缝化学成份的稀释率为 0。焊接接头的拉伸强度为 6 30 MPa。面弯角大于等于 12 0°,背弯角为 180°,侧弯角大于等于 10 0°。焊接接头具有良好的综合机械性能。
2001(6):478-480.
Abstract:
A precious continuous casting technique and equipment suitable for the production of Ag and its alloys are discribed in this paper. The equipment possesses the advantages of precision, miniaturization, vacuum or gass protective melting and casting, especially suitable for producing the precious metals demanding high purity, containing easily volatile components and severely oxidized owing to gass absorption under molten state.The purity and spray of Ag 28 Cu filler produced using the continuous casting technique can reach the first level.
A precious continuous casting technique and equipment suitable for the production of Ag and its alloys are discribed in this paper. The equipment possesses the advantages of precision, miniaturization, vacuum or gass protective melting and casting, especially suitable for producing the precious metals demanding high purity, containing easily volatile components and severely oxidized owing to gass absorption under molten state.The purity and spray of Ag 28 Cu filler produced using the continuous casting technique can reach the first level.
