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Morphology and Frictional Characteristics Under Electrical Currents of Al_2O_3/Cu Composites Prepared by Internal Oxidation 被引量:7
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作者 刘瑞华 宋克兴 +3 位作者 贾淑果 徐晓峰 郜建新 国秀花 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2008年第3期281-288,共8页
Two Al2O3/Cu composites containing 0.24 wt.% Al2O3 and 0.60 wt.% Al2O3 separately are prepared by internal oxidation. Effects of sliding speed and pressure on the frictional characteristics of the composites and coppe... Two Al2O3/Cu composites containing 0.24 wt.% Al2O3 and 0.60 wt.% Al2O3 separately are prepared by internal oxidation. Effects of sliding speed and pressure on the frictional characteristics of the composites and copper against brass are investigated and compared. The changes in morphology of the sliding surface and subsurface are examined with scanning electron microscope (SEM) and energy dispersive X-ray spectrum (EDS). The results show that the wear resistance of the Al2O3/Cu composites is superior to that of copper under the same conditions, Under a given electrical current, the wear rate of Al2O3/Cu composites decreases as the Al2O3-content increases, However, the wear rates of the Al2O3/Cu composites and copper increase as the sliding speed and pressure increase under dry sliding condition. The main wear mechanisms for Al2O3/Cu composites are of abrasion and adhesion; for copper, it is adhesion, although wear by oxidation and electrical erosion can also be observed as the speed and pressure rise. 展开更多
关键词 al2o3/cu composite internal oxidation friction and wear surface morphology current carder
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Hot deformation and processing maps of Al_2O_3/Al composites fabricated by flake powder metallurgy 被引量:1
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作者 栾佰峰 邱日盛 +4 位作者 李春红 杨晓芳 李志强 张荻 刘庆 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第4期1056-1063,共8页
The deformation behaviors of Al2O3/Al composites were investigated by compressive tests conducted at temperature of 300-450 °C and strain rates of 0.001-1.0 s-1 with Gleeble-1500 D thermal simulator system. The r... The deformation behaviors of Al2O3/Al composites were investigated by compressive tests conducted at temperature of 300-450 °C and strain rates of 0.001-1.0 s-1 with Gleeble-1500 D thermal simulator system. The results show that the flow stress increases with increasing strain rate and decreasing temperature. The hyperbolic sine constitutive equation can describe the flow stress behavior of Al2O3/Al composites, and the deformation activation energy and constitutive equations were calculated. The processing maps of Al2O3/Al-2 μm and Al2O3/Al-1 μm composites at strain of 0.6 were obtained and the optimum processing domains are in ranges of 300-330 °C, 0.007-0.03 s-1 and 335-360 °C, 0.015-0.06 s-1 for hot working, respectively. The instability zones of flow behavior can also be recognized by the maps. 展开更多
关键词 al2o3/al composites flake powder metallurgy flow stress processing map
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Effect of CuO particle size on synthesis temperature and microstructure of Al_2O_(3p)-Al composites from Al-CuO system 被引量:1
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作者 赵鸽 史志铭 +1 位作者 塔娜 张瑞英 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第12期3901-3906,共6页
Al2O3p-Al composites were synthesized using an in-situ reaction in the 80%Al-20%CuO (mass fraction) system. The effects of the CuO particle size on the synthesis temperature and microstructure of the composites were... Al2O3p-Al composites were synthesized using an in-situ reaction in the 80%Al-20%CuO (mass fraction) system. The effects of the CuO particle size on the synthesis temperature and microstructure of the composites were investigated by various methods. The results indicate that the CuO particle size has a significant effect on the temperature at which the complete reaction in the Al-CuO system occurs:the temperature is 200 ℃ lower in the Al-CuO system containing CuO particles with sizes less than 6μm than that containing CuO particles with sizes less than 100μm. The interfacial bonding between Al2O3 particles and Al is not complete when the temperature is below a critical value. The morphology of the Al2O3 particles varies from ribbon-like shape to near spherical shape when the temperature is above a critical value. These two critical temperatures are affected by the particle size of CuO, and the critical temperature of the sample containing CuO particles with sizes less than 6μm is 100 ℃ lower than that of the sample containing CuO particles with sizes less than 100μm. 展开更多
关键词 cuo particle size synthesis temperature al2o3p-al composite
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Reaction thermodynamics and kinetics on in situ Al_2O_3/Cu composites 被引量:4
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作者 Li Guobin(李国彬) 1, Wu Jianjun(武建军) 1, Guo Quanmei(郭全梅) 2, Jiang Yanfei(姜延飞) 1, Shen Yutian(申玉田) 1, Lei Tingquan(雷廷权) 2 1. Department of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, P.R.Chi 《中国有色金属学会会刊:英文版》 CSCD 1999年第3期617-622,共6页
The preferred internal oxidation of aluminum in Cu Al alloy was used to obtain in situ Al 2O 3/Cu composites. The reinforcement particles were mainly γ Al 2O 3, some θ Al 2O 3 and a little α Al 2O 3. Thermodynamics... The preferred internal oxidation of aluminum in Cu Al alloy was used to obtain in situ Al 2O 3/Cu composites. The reinforcement particles were mainly γ Al 2O 3, some θ Al 2O 3 and a little α Al 2O 3. Thermodynamics analyses show that the chemical reactions are 3Cu 2O+2Al=6Cu+Al 2O 3 or 3CuO+2Al=3Cu+Al 2O 3. A related equilibrium diagram was drawn. The experiments and investigation show that the formation rate of Al 2O 3 was controlled by the diffusion of oxygen in matrix. 展开更多
关键词 al 2o 3/cu compositeS internal oxidation THERMoDYNAMICS kineticsDocument code: A
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Influence of Adding Ti Powder in Preform on Microstructure and Mechanical Properties of Al_2O_3p/Steel Composites by Squeeze Casting 被引量:4
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作者 卢德宏 WANG Jian +1 位作者 YU Jing JIANG Yehua 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2018年第1期164-170,共7页
To improve the mechanical properties of alumina particulates reinforced steel matrix composite, Ti powder was added into the alumina preform, a 5140 steel matrix composite was fabricated by squeeze casting, and the in... To improve the mechanical properties of alumina particulates reinforced steel matrix composite, Ti powder was added into the alumina preform, a 5140 steel matrix composite was fabricated by squeeze casting, and the influences of Ti powder on the microstructure, hardness and bending strength of the composite were investigated, compared with the composite without adding Ti powder. Applied Ti powder and alumina particulates were 10-25 μm and 100-180 μm in size, respectively. Both composites were successfully fabricated, however Ti powder addition increased the infiltration thickness of the composite. In the Ti contained composite, a TiC film in micron scale is formed on the surface of alumina particles, many TiC aggregates are dispersed in the steel matrix without obvious remaining Ti powder. The hardness and the three-point bending strength of the composite reach 49.5 HRC and 1 018 MPa, respectively, which are 17.9% and 52.4% higher than those of the composite in the absence of Ti addition. Fracture morphology shows that the debonding of alumina particulates is eliminated for the composite in the presence of Ti addition. Sessile drop test shows the average wetting angle between 5140 steel and that of Ti coated Al2O3 is about 82.15°, much lower than the wetting angle 150° between steel and pure Al2O3. Therefore, the increase in the mechanical properties of the composite is attributed to the improvement of Al2O3 p/steel interface wetting and bonding by adding Ti powder in the preform. 展开更多
关键词 squeeze casting al2o3 steel matrix composites interface mechanical properties
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Al-Si/Al_2O_3 in situ composite prepared by displacement reaction of CuO/Al system 被引量:3
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作者 Zhang Jing Yu Huashun +1 位作者 Chen Hongmei Min Guanghui 《China Foundry》 SCIE CAS 2010年第1期19-23,共5页
Al2O3 particle-reinforced ZL109 composite was prepared by in situ reaction between CuO and Al2O3 . The microstructure was observed by means of OM, SEM and TEM. The Al2O3 particles in sub-micron sizes distribute unifo... Al2O3 particle-reinforced ZL109 composite was prepared by in situ reaction between CuO and Al2O3 . The microstructure was observed by means of OM, SEM and TEM. The Al2O3 particles in sub-micron sizes distribute uniformly in the matrix, and the Cu displaced from the in situ reaction forms net-like alloy phases with other alloy elements. The hardness and the tensile strength of the composites at room temperature have a slight increase as compared to that of the matrix. However, the tensile strength at 350℃ has reached 90.23 MPa, or 16.92 MPa higher than that of the matrix. The mechanism of the reaction in the CuO/AI system was studied by using of differential scanning calorimetry(DSC) and thermodynamic calculation. The reaction between CuO and Al involves two steps. First, CuO reacts with Al to form Cu20 and Al2O3 at the melting temperature of the matrix alloy, and second, Cu20 reacts with Al to form Cu and Al2O3 at a higher temperature. At ZL109 casting temperature of 750- 780 ℃, the second step can also take place because of the effect of exothermic reaction of the first step. 展开更多
关键词 aluminium matrix composites in situ reaction al2o3 particles ZL109 cuo
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Al2_3/Al2O3 Joint Brazed with Al2O3-particulate-contained Composite Ag-Cu-Ti Filler Material 被引量:2
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作者 Jianguo YANG Hongyuan FANG and Xin WANState Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第5期782-784,共3页
Microstructure and interracial reactions of Al2O3 joints brazed with Al2O3-particulate-contained composite Ag-Cu-Ti filler material were researched by scanning electron microscopy (SEM), electron probe microscopy an... Microstructure and interracial reactions of Al2O3 joints brazed with Al2O3-particulate-contained composite Ag-Cu-Ti filler material were researched by scanning electron microscopy (SEM), electron probe microscopy analysis (EPMA), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The interracial reaction layer thickness of joints brazed with conventional active filler metal and active composite filler materials with different volume fraction of Al2O3 particulate was also studied. The experimental results indicated although there were Al2O3 particulates added into active filler metals, the time dependence of interracial layer growth of joints brazed with active composite filler material is t^1/2 as described by Fickian law as the joints brazed with conventional active filler metal. 展开更多
关键词 composite filler materials BRAZE Interface al2o3
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High Temperature Flow Stress Prediction of Nano-Al_2O_3/Cu Composite Using an Artificial Neural Network 被引量:1
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作者 GAO Jian-xin XU Xiao-feng +3 位作者 SONG Ke-xing LI Pei-quan GUO Xiu-hua LIU Rui-hua 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2006年第B12期36-40,共5页
Alumina dispersion strengthened copper composite (nano-Al2O3/Cu composite) was recently emerged as a kind of potentially viable and attractive engineering material for applications requiring high strength, high ther... Alumina dispersion strengthened copper composite (nano-Al2O3/Cu composite) was recently emerged as a kind of potentially viable and attractive engineering material for applications requiring high strength, high thermal and electrical conductivities and resistance to softening at elevated temperatures. The nano-Al2O3/Cu composite was produced by internal oxidation. The microstructures of the composite were analyzed by the TEM and its hot deformation behavior was investigated by means of continuous compression tests performed on a Gleeble 1500 thermo-simulator. Making use of the modified algorithm-Levenberg-Marquardt (L-M) algorithm BP neural network, a model for predicting the flow stresses during hot deformation was set up on the base of the experimental data. Results show that the microstructures of the composite are characterized by uniform distribution of nano-Al2O3 particles in Cu-matrix. The sliding of dislocations is the main deformation mechanism. The dynamic recovery is the main softening mode with the flow stress decreasing gently from 500℃ to 850 ~C. The recrystallization of Cu-matrix can be retarded late into as high as 850 ℃, when it happens only partially. The well-trained BP neural network model can accurately describe the influence of the temperature, strain rate, and true strain on the flow stresses, therefore, it can precisely predict the flow stresses of the composite under given deforming conditions and provide a new way to optimize hot deforming process parameters. 展开更多
关键词 al2o3/cu composite flow stress neural network hot deformation
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Microstructure and evolution of(TiB_2+Al_2O_3)/NiAl composites prepared by self-propagation high-temperature synthesis 被引量:3
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作者 宋晓杰 崔洪芝 +1 位作者 曹丽丽 P.Y.GULYAEV 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第7期1878-1884,共7页
(TiB2+Al2O3)/NiAl composites were synthesized by self-propagation high-temperature synthesis, and their phase compositions, microstructures and evolution modes were studied. The microstructures and shapes vary with... (TiB2+Al2O3)/NiAl composites were synthesized by self-propagation high-temperature synthesis, and their phase compositions, microstructures and evolution modes were studied. The microstructures and shapes vary with the TiB2+Al2O3 content in the NiAl matrix. TiB2 particles take a great variety of elementary shapes such as white bars, plates, herringbones, regular cubes and cuboids. These results outline a strategy of self-assembly processes in real time to build diversified microstructures. Some TiB2 grains in sizes of 2-5μm are embeded in Al2O3 clusters, while a small number of TiB2 particles disperse in the NiAl matrix. It is believed that the higher the TiB2+Al2O3 content is, the more the regular shapes and homogeneous distributions of TiB2 and Al2O3 will be present in the NiAl matrix. 展开更多
关键词 (TiB2al2o3)/Nial composites self-propagation high-temperature synthesis MICRoSTRUCTURE evolution mechanism
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Preparation of Al_2O_3/Au nano-laminated composite coatings and their oxidation resistance on stainless steel 被引量:1
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作者 高俊国 陆峰 +2 位作者 汤智慧 王长亮 何业东 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第10期2491-2497,共7页
Al2O3/Au nano-laminated composite coatings were prepared by means of magnetron sputtering. The coating was compact and comprised of nano-laminated Al2O3 and Au layers. High temperature cyclic oxidation test was employ... Al2O3/Au nano-laminated composite coatings were prepared by means of magnetron sputtering. The coating was compact and comprised of nano-laminated Al2O3 and Au layers. High temperature cyclic oxidation test was employed to investigate the oxidation resistance of the composite coatings. The results revealed that the applied Al2O3/Au nano-laminated composite coatings improved the oxidation and spallation resistance of the stainless steel substrate significantly. The mechanism accounting for oxidation resistance was related with the suppression of inward oxygen diffusion and selective oxidation of Cr in the substrate. The mechanism accounting for spallation resistance was attributed to the relaxation of thermal stress by the nano-laminated structure. 展开更多
关键词 al2o3/Au composite coatings magnetron sputtering oxidation resistance spallation resistance
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High Temperature Deformation of Al_2O_3/Cu Composites
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作者 Jianjun WU. Yun ZHANG, Yanfei JIANG and Meiyun XUE Department of Material Science and Engineering, Hebei University of Technology, Tianjin 300130, China Tingquan LEI School of Materials Science and Engineering, Harbin Institute of Technology, Uarbin 15000 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第3期325-328,共4页
This work concerns with the high temperature deformation of internally oxidized Al2O3/Cu composites. The investigation revealed that dispersive alumina can obstruct dislocation sliding and define the subgrain size the... This work concerns with the high temperature deformation of internally oxidized Al2O3/Cu composites. The investigation revealed that dispersive alumina can obstruct dislocation sliding and define the subgrain size thereby improve significantly the strength of the materials at high temperature. The sliding of dislocations is a main deformation mechanism in the given temperature range. The sliding of grain boundary and diffusive creep play important roles at high temperature and low strain rate. The dispersoids can raise the recrystallization temperature to higher than 1223 K. Dynamic recovery is a main softening way under the experimental conditions. Higher deformation rate and lower deformation temperature imply a higher flow stress. 展开更多
关键词 High Temperature Deformation of al2o3/cu composites cu al
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Self-Propagating High-Temperature Reductive Synthesis of TiB_2-Al_2O_3 Composite Powders
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作者 于志强 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2007年第1期48-51,共4页
TiB2-Al2O3 composite powders were produced by self-propagating high-temperature synthesis(SHS) method with reductive process from B2O3-TiO2-AI system. X-ray diffraction(XRD) and scanning electron microscopy(SEM... TiB2-Al2O3 composite powders were produced by self-propagating high-temperature synthesis(SHS) method with reductive process from B2O3-TiO2-AI system. X-ray diffraction(XRD) and scanning electron microscopy(SEM) analyses show the presence of TiB2 and Al2O3 only in the composite powders produced by SHS. The powders are uniform and free-agglomerate. Transmission electron microscopy (TEM) and high resolution electron microscopy (HREM) observation of microstructure of the composite powders indicate that the interfaces of the TiB2-Al2O3 bond well, without any interfacial reaction products. It is proposed that the good interfacial bonding of the composite powders can be resulted from the TiB2 particles crystallizing and growing on the Al2O3 particles surface with surface defects acting as nucleation centers. 展开更多
关键词 SHS with reductive process TiB2-al2o3 composite powders B2o3+Tio2al system microstructure
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Microstructure and Mechanical Properties of Submicron-grained NiAl-Al_2O_3 Composite Prepared by Pulse Current Auxiliary Sintering
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作者 徐桂华 卢振 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2012年第4期715-720,共6页
Dense and submicron-grained NiAl-Al2O3 composite was fabricated by pulse current auxiliary sintering(PCAS).Its microstructure was analyzed by XRD,SEM and TEM,and its mechanical behavior was evaluated through compres... Dense and submicron-grained NiAl-Al2O3 composite was fabricated by pulse current auxiliary sintering(PCAS).Its microstructure was analyzed by XRD,SEM and TEM,and its mechanical behavior was evaluated through compression test and fracture toughness test.The average grain sizes of NiAl and Al2O3 are about 200 nm and 100 nm respectively.The Al2O3 particles dispersed in NiAl matrix,forming intergranular structure and intragranular structure.During sintering,Al2O3 particles were remarkably spherized due to the unique sintering mechanism of PCAS,which is beneficial to the improvement of toughness.The NiAl-Al2O3 composite exhibits high compressive yield strength,whether at room temperature or elevated temperature.Its room-temperature(23 ℃) and elevated-temperature(1 200 ℃) compressive yield strength are up to 2 050 MPa and 140 MPa,respectively.Meanwhile,its fracture toughness is significantly enhanced,which is up to 8.2 MPa?m1/2.It is suggested that the main strengthening-toughening mechanisms are grain refinement strengthening and Al2O3 dispersion strengthening.The fracture of larger NiAl grain is the transgranular cleavage and this is induced by crack tip deflection and grain boundary weakening which are caused by intergranular and intragranular Al2O3 particles,respectively. 展开更多
关键词 NIal al2o3 composite pulse current auxiliary sintering microstructure mechanical behavior
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Recovery of valuable elements from spent YBa_2Cu_3O_(7-x)/Agcomposite superconductor bulks
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作者 李凤华 李英楠 +1 位作者 张聪聪 樊占国 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第S1期192-197,共6页
Silver as a highly conductive metal is usually doped in YBa2Cu3O7-x superconductor bulks to improve critical current density of YBa2Cu3O7-x superconductor.The valuable metal elements silver,yttrium,barium and copper i... Silver as a highly conductive metal is usually doped in YBa2Cu3O7-x superconductor bulks to improve critical current density of YBa2Cu3O7-x superconductor.The valuable metal elements silver,yttrium,barium and copper in waste YBa2Cu3O7-x/Ag composite superconductor bulks were recovered,respectively.Silver was recovered with process at first,the waste was dissolved by nitric acid and silver chloride was precipitated by adding chloride acid,then silver pig was obtained by melting silver chloride together with sodium carbonate at 1 000℃.The effective factors on recovery ratio and purity of silver were studied.The chemical analysis proves that the purity of silver ingot is 95.86%.The recovery ratio of silver is calculated to be 92.56%.The loss of silver may be due to the loss of silver chloride during filtering and the volatilization of silver when silver chloride and sodium carbonate are smelted at high temperature.For other three metal elements,Y3 +,Ba 2+and Cu 2+,in the surplus waste liquid after recovering silver, they were separated with the sequence of barium,copper and then yttrium step by step.First,sulfate acid was used to precipitate barium sulfate.Then,sodium sulfide was added to the surplus solution so that copper could be separated as copper sulfide.During this separation procedure,it was important to control the pH value to be 1-2.After that,oxalic acid was added into the surplus solution to obtain yttrium oxalate.Finally,yttrium oxide was formed by burning yttrium oxalate.The XRD results indicate that the final products are all single-phase compounds as BaSO4,CuS and Y2O3,respectively. 展开更多
关键词 RECoVERY waste YBa2cu3o7-x/Ag composite leaching SMELTING precipitation
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In-situ Preparation of Al/TiAl_3(P) Composite by Direct Reaction between Molten Al and TiO_2 Powder
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作者 Yuyong CHEN Ziyong CHEN Qu SHU and Geying AN(National Defense Precision Hot Processing Lab., Harbin Institute of Technology Harbin 150006, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1998年第6期569-570,共2页
TiAl3 particle reinforced pure Al composite has been made by direct reaction among molten Al, TiO2 and a flux. The composite exhibits high Synthetically properties. The strength and hardness are higher than those of p... TiAl3 particle reinforced pure Al composite has been made by direct reaction among molten Al, TiO2 and a flux. The composite exhibits high Synthetically properties. The strength and hardness are higher than those of pure Al matrix by 71.5% and 134% respectively However, the elongation is 20.36%, slightly lower than that of the Al matrix. 展开更多
关键词 Tio Tial In-situ Preparation of al/Tial3 composite by Direct Reaction between Molten al and Tio2 powder
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A Comparative Study on Dry Sliding Wear Characteristics of Al2O3 and Bone Powder Filled Hybrid Composites
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作者 Sudeep Deshpande T. Rangaswamy 《Journal of Minerals and Materials Characterization and Engineering》 2016年第2期164-180,共17页
The aim of the research was to develop E-glass/jute fiber reinforced epoxy composites with an addition of Al<sub>2</sub>O<sub>3</sub> and bone powder by using hand layup technique and to compar... The aim of the research was to develop E-glass/jute fiber reinforced epoxy composites with an addition of Al<sub>2</sub>O<sub>3</sub> and bone powder by using hand layup technique and to compare tribological properties of these composites under similar test conditions. The wear experiments were designed according to Taguchi’s (L<sub>27</sub>) orthogonal array with three control variables such as sliding velocity, filler content and normal load. The results indicated that the normal load for Al<sub>2</sub>O<sub>3</sub> and filler content for bone powder emerged as the significant factors affecting specific wear rate of hybrid composites. An addition of 10 wt% of bone powder or Al<sub>2</sub>O<sub>3</sub> into E-glass/jute fiber reinforced epoxy composites increased the wear resistance considerably, and natural waste bone powder can be used instead of ceramic filler Al<sub>2</sub>O<sub>3</sub> in hybrid composites. After the analysis of control factors, an optimal factor setting has been suggested for specific wear rate and coefficient of friction. Further, the scanning electron microscopy (SEM) images for worn surfaces of hybrid composites were studied. Finally, a confirmation test was carried out to validate the results. 展开更多
关键词 al2o3 Bone powder Wear Test Taguchi Analysis SEM
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Thermal shock fatigue behavior of TiC/Al_2O_3 composite ceramics 被引量:6
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作者 SI Tingzhi LIU Ning +1 位作者 ZHANG Qing' an YOU Xianqing 《Rare Metals》 SCIE EI CAS CSCD 2008年第3期308-314,共7页
The thermal shock fatigue behaviors of pure hot-pressed alumina and 30 wt.% TiC/Al2O3 composites were studied. The effect of TiC and Al2O3 starting particle size on the mechanical properties of the composites was disc... The thermal shock fatigue behaviors of pure hot-pressed alumina and 30 wt.% TiC/Al2O3 composites were studied. The effect of TiC and Al2O3 starting particle size on the mechanical properties of the composites was discussed. Indentation-quench test was conducted to evaluate the effect of thermal fatigue temperature difference (ΔT) and number of thermal cycles (Ⅳ) on fatigue crack growth (Δa). The mechanical properties and thermal fatigue resistance of TiC/Al203 composites are remarkably improved by the addition of TiC. The thermal shock fatigue of monolithic alumina and TiC/Al2O3 composites is due to a "true" cycling effect (thermal fatigue). Crack deflection and bridging are the predominant reasons for the improvement of thermal shock fatigue resistance of the composites. 展开更多
关键词 ceramic matrix composites TiC/al2o3 composites thermal shock fatigue fatigue behavior fatigue resistance
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IN SITU PROCESSING OF Al_(2)O_(3) WHISKERS REINFORCED Ti-Al INTERMETALLIC COMPOSITES 被引量:6
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作者 F.Wang Z.K.Fan J.F.Zhu 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2006年第6期432-440,共9页
In situ Al2O3 whiskers reinforced Ti-Al intermetallic composites were fabricated at ~1200℃ by reaction sintering of cold-consolidated fillets consisting mainly of Ti, Al, and different additives. The phases and micro... In situ Al2O3 whiskers reinforced Ti-Al intermetallic composites were fabricated at ~1200℃ by reaction sintering of cold-consolidated fillets consisting mainly of Ti, Al, and different additives. The phases and microstructures of the sintered composites were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The process of synthesis was investigated using differential thermal analysis (DTA). The effects of processing parameters and additives on the microstructures of the composites and the development of whisker were examined. It is found that the morphology of the whisker is strongly influenced by the additives, the exothermal reaction process, and the processing parameters. 展开更多
关键词 in situ al2o3 whisker Ti-al intermetallic composite ADDITIVE reaction process
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Characterization and performance of Cu/ZnO/Al_2O_3 catalysts prepared via decomposition of M(Cu,Zn)-ammonia complexes under sub-atmospheric pressure for methanol synthesis from H_2 and CO_2 被引量:7
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作者 Danjun Wang Jun Zhao +1 位作者 Huanling Song Lingjun Chou 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2011年第6期629-634,共6页
Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M(Cu,Zn)-ammonia complexes (DMAC) at various temperatures.The catalysts were characterized in d... Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M(Cu,Zn)-ammonia complexes (DMAC) at various temperatures.The catalysts were characterized in detail,including X-ray diffraction,N2 adsorption-desorption,N2O chemisorption,temperature-programmed reduction and evolved gas analyses.The influences of DMAC temperature,reaction temperature and specific Cu surface area on catalytic performance are investigated.It is considered that the aurichalcite phase in the precursor plays a key role in improving the physiochemical properties and activities of the final catalysts.The catalyst from rich-aurichalcite precursor exhibits large specific Cu surface area and high space time yield of methanol (212 g/(Lcat·h);T=513 K,p=3MPa,SV=12000 h-1). 展开更多
关键词 decomposition of M(cu Zn)-ammonia complexes cu/Zno/al2o3 catalyst Co2 hydrogenation methanol synthesis
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Kinetics of Oxidation for β-Sialon in Diphase β-Sialon/Al_2O_3 Composite 被引量:5
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作者 Youfen LI Yanruo HONG XangChong ZHONG and Tingshou LI(National Laboratory on Solid Electrolytes and Metallurgical Testing Techniques, University of Science & TechnologyBeijing, Beijing 100083, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1999年第1期21-24,共4页
Non-isothermal kinetic research has been carried out on oxidation behavior of β-Sialon in diphaseβ-Sialon/Al_2O_3 composite at high temperatures. A kinetic formula is established for non-isothermal oxidation process... Non-isothermal kinetic research has been carried out on oxidation behavior of β-Sialon in diphaseβ-Sialon/Al_2O_3 composite at high temperatures. A kinetic formula is established for non-isothermal oxidation process of β-Sialon. The rate of oxidation process is controlled by chemicalreaction at the initial stage and then by diffusion. The apparent activation energies and appar-ent rate constants at different temperatures are determined by treating TG data of the overallprocess. 展开更多
关键词 al Kinetics of oxidation for Sialon/al2o3 composite
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