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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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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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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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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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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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PREPARATION,CHARACTERIZATION AND HYDROGENATION PROPERTY OF POLYMER-SUPPORTED Pd-Fe_2O_3 COMPOSITE CATALYSTS
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作者 ZHANG Shengmin HU Weibing ZHANG Manzheng Wuhan University of Technology Hubei Research Institute of Chemistry 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 1999年第4期48-52,共5页
A series of polymer- supported Pd -Fe2O3 composite catalysts were prepared and their hydrogenation property mas investigated. It was found that the above catalysts have good catalytic hydrogenation activity for carbon... A series of polymer- supported Pd -Fe2O3 composite catalysts were prepared and their hydrogenation property mas investigated. It was found that the above catalysts have good catalytic hydrogenation activity for carbon - carbon double bonds systems and reusability. Furthermore, XPS and IR spectra shouted that active component in the composite catalysts is atomic Pd(0). An addition of a small amount of Fe2O3 has a promotive action upon hydrogenation activity of the catalysts, which indicated that there are some strong interactions (electron transfer) between Pd(0) and Fe(Ⅲ) species. Based on these results, a possible catalytic hydrogenation mechanism was also suggested. 展开更多
关键词 functional material polymet-sup- ported catalyst composite Pd - F2o3/polystyrene HYDRoGENATIoN mechanism
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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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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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Effect of hot extrusion on microstructure and tribological behavior of Al_(2)O_(3p) reinforced 7075 aluminum-matrix composites 被引量:4
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作者 LEI Yu-shun YAN Hong +4 位作者 WEI Zhi-fan XIONG Jun-jie ZHANG Peng-xiang WAN Jian-ping WANG Zhi-lu 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第8期2269-2284,共16页
The effects of hot extrusion and addition of Al_(2)O_(3p) on both microstructure and tribological behavior of 7075 composites were investigated via optical microscopy(OM),scanning electron microscopy(SEM),energy dispe... The effects of hot extrusion and addition of Al_(2)O_(3p) on both microstructure and tribological behavior of 7075 composites were investigated via optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),and transmission electron microscopy(TEM).The experimental consequences reveal that the optimal addition of Al_(2)O_(3p) was 2 wt%.After hot extrusion,the Mg(Zn,Cu,Al)2 phases partially dissolve into the matrix and generate many uniformly distributed aging precipitation particles,the Al_(7)Cu_(2)Fe phases are squeezed and broken,and the Al_(2)O_(3p) become uniform distribution.The microhardness of as-extruded 2 wt%Al_(2)O_(3p)/7075 composites reaches HV 170.34,increased by 41.5%than as-cast composites.The wear rate of as-extruded 2 wt%Al_(2)O_(3p)/7075 composites is further lower than that of as-cast composites under the same condition.SEM-EDS analyses reveal that the reinforced wear resistance of composites can put down to the protective effect of the Al_(2)O_(3p) reinforced transition layer.After hot extrusion,the transition layer becomes stable,which determines the reinforced wear resistance of the as-extruded composites. 展开更多
关键词 7075 alloy al2o3P compositeS hot extrusion MICRoSTRUCTURE tribological behavior
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Effects of Cerium Oxide on Ni/Al_2O_3 Catalysts for Decomposition of CH_4 and C_2H_4 被引量:4
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作者 杨咏来 李文钊 徐恒泳 《Journal of Rare Earths》 SCIE EI CAS CSCD 2003年第4期427-429,共3页
Characteristics of carbon deposition of CH 4 and C 2H 4 decomposition over supported Ni and Ni Ce catalysts were studied by using a pulse reaction as well as BET, TPR, XPS and hydrogen chemisorption techniques. It... Characteristics of carbon deposition of CH 4 and C 2H 4 decomposition over supported Ni and Ni Ce catalysts were studied by using a pulse reaction as well as BET, TPR, XPS and hydrogen chemisorption techniques. It is found that there is a metal semiconductor interaction (MScI) in the Ni Ce catalyst, and the effect of MScI on the carbon deposition of CH 4 decomposition is opposite to that of C 2H 4. A novel model of carbon deposition of CH 4 or C 2H 4 decomposition was proposed. 展开更多
关键词 catalytic chemistry Ni/al 2o 3 catalyst cerium oxide METHANE ETHYLENE DEcompositIoN rare earths
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Effect of MoSi_2 content on dielectric and mechanical properties of MoSi_2/Al_2O_3 composite coatings 被引量:5
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作者 WU Zhi-hong ZHOU Wan-cheng +1 位作者 LUO Fa ZHU Dong-mei 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第1期111-116,共6页
Molybdenum disilicide (MoSi2) sheath and aluminum oxide (Al2O3) core blended powders were fabricated by spray drying. A derived coating material was produced for the application as microwave absorbers using the as... Molybdenum disilicide (MoSi2) sheath and aluminum oxide (Al2O3) core blended powders were fabricated by spray drying. A derived coating material was produced for the application as microwave absorbers using the as prepared powders by atmospheric plasma spray (APS) technology. The effects of MoSi2/Al2O3 mass ratio on the dielectric and physical mechanical properties of the composite coatings were investigated. When the MoSi2 content of the composites increases from 0 to 45%, the flexure strength and fracture toughness improve from 198 to 324 MPa and 3.05 to 4.82 MPa-m1/2 then decline to 310 MPa and 4.67 MPa-m1/2, respectively. The dielectric loss tangent increases with increasing MoSi2 content, and the real part of permittivity decreases conversely over the frequency range of 8.2-12.4 GHz. These effects are due to the agglomeration of early molten MoSi2 particles and the increase of the electrical conductivity with increasing MoSi2 content. 展开更多
关键词 MoSi2/al2o3 composite coating atmospheric plasma spraying mechanical properties dielectric properties
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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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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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Aluminum matrix composites reinforced by in situ Al_2O_3 and Al_3Zr particles fabricated via magnetochemistry reaction 被引量:3
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作者 赵玉涛 张松利 陈刚 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第11期2129-2133,共5页
Aluminum matrix composites reinforced by in situ Al2O3 and Al3Zr particles are fabricated from A356-Zr(CO3)2 system via magnetochemistry reaction,and the morphologies,sizes and distributions of the in situ particles a... Aluminum matrix composites reinforced by in situ Al2O3 and Al3Zr particles are fabricated from A356-Zr(CO3)2 system via magnetochemistry reaction,and the morphologies,sizes and distributions of the in situ particles as well as the microstructures,mechanical mechanisms of the composites are investigated by XRD,SEM,TEM and in situ tensile tests.The results indicate that with the pulsed magnetic field assistance,the morphologies of the in situ particles are mainly with ball-shape,the sizes are in nanometer scale and the distributions in the matrix are uniform.The interfaces between the in situ particles and the aluminum matrix are net and no interfacial outgrowth is observed.These are due to the strong vibration induced by the applied magnetic field in the aluminum melt,which in turn,accelerates the melt reactions.The effects of the magnetic field on the above contributions are discussed in detail. 展开更多
关键词 aluminum matrix composites magnetochemistry reaction al2o3 al3ZR in situ tensile
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Properties of Hot-Pressed Al_2O_3-Fe Composites 被引量:4
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作者 M.M.El-Sayed Seleman, Xudong SUN and Liang ZUO Department of Materials Science and Engineering, Northeastern University, Shenyang 110006, China K.A.Khalil Powder Metallurgy Institute, Central South University, Changsha 410083, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第5期538-542,共5页
Alumina-(0 similar to 20 vol. pct) iron composites were fabricated by hot-pressing of well-mixed-alumina and iron powders at 1400 degreesC and 30 MPa for 30 min. Hot-pressed bodies with nearly theoretical density were... Alumina-(0 similar to 20 vol. pct) iron composites were fabricated by hot-pressing of well-mixed-alumina and iron powders at 1400 degreesC and 30 MPa for 30 min. Hot-pressed bodies with nearly theoretical density were obtained for addition up to 10 vol. pct Fe, but relative density decreased gradually with further increase in Fe addition. The materials exhibit a homogeneous dispersion of Fe. Fracture strength of the composites exhibits a maximum value of 604 MPa at 15 vol. pct Fe, which is 1.5 times that of alumina alone. Fracture toughness increases with the increase in Fe content, reaching 7.5 MPa.m(1/2) at 20 vol. pct Fe. The theoretical values of fracture toughness was calculated and compared with the experimental one. Toughening mechanisms of the composites are also discussed. 展开更多
关键词 FE Properties of Hot-Pressed al2o3-Fe composites al
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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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MICROSTRUCTURES AND MECHANICAL PROPERTIES OF IN-SITU Al_2O_3/TiAl COMPOSITES BY EXOTHERMIC DISPERSION METHOD 被引量:4
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作者 T.T. Ai 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2008年第6期437-443,共7页
In-situ Al2O3/TiAl composites were fabricated by pressure-assisted exothermic dispersion (PAXD) method from elemental powder mixtures of Ti, Al, TiO2, and Nb2O5. The microstructures and mechanical properties of the ... In-situ Al2O3/TiAl composites were fabricated by pressure-assisted exothermic dispersion (PAXD) method from elemental powder mixtures of Ti, Al, TiO2, and Nb2O5. The microstructures and mechanical properties of the as-sintered composites are investigated. The results show that the as-sintered products consist of γ-TiAl, α2-Ti3Al, Al2O3, and NbAl3 phases. Microstructure analysis indicates that Al2O3 particles tend to disperse on the grain boundaries. Application of a moderate pressure of 35 MPa at 1200℃ yields Al2O3/TiAl composites with fine Al2O3 reinforcement and a discontinuous network linking by Al2O3 particles. The aluminide component has a fine submicron γ +α2 lamellar microstructure. With increasing Nb2O5 content, Al2O3 particles are dispersed uniformly in the matrix. The hardness of the composites increases gradually, and the bending strength and fracture toughness of the composites reach to the maximum value, respectively. 展开更多
关键词 al2 o3/Tial composites MICRoSTRUCTURE Mechanical properties
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Effect of Al2O3np on the Properties and Microstructure of B4Cp/Al Composites 被引量:4
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作者 LIU Tingting PANG Xiaoxuan +2 位作者 XIAN Yajiang LUO Hao ZHANG Pengcheng 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2020年第3期514-519,共6页
Aluminum-matrix boron carbide (B4Cp/Al) is a kind of neutron absorbing material widely used in nuclear spent fuel storage. In order to improve the tensile property of B4Cp/Al composites, a new type of nano-Al2O3 parti... Aluminum-matrix boron carbide (B4Cp/Al) is a kind of neutron absorbing material widely used in nuclear spent fuel storage. In order to improve the tensile property of B4Cp/Al composites, a new type of nano-Al2O3 particle (Al2O3np) reinforced B4Cp/Al + Al2O3np composites were prepared by powder metallurgy method. The Monte Carlo particle transport program (MCNP) was used to determine the influence of Al2O3np on the thermal neutron absorptivity of composites. The universal material testing machine and scanning electron microscope (SEM) were used to study the mechanical properties, microstructure and fracture morphology of B4Cp/Al composites. The results indicated that the neutron absorption properties of B4Cp/Al composites were not affected by the addition of nano-Al2O3 particles in the range of 1 wt%-15 wt%. The addition of Al2O3np can obviously reduce the grain size of B4Cp/Al matrix metals thus improve the tensile strength of the composites. The addition threshold of Al2O3np is about 2.5 wt%. Both B4Cp and Al2O3np change the fracture characteristics of the composites from toughness to brittleness, and the latter is more important. 展开更多
关键词 B4Cp/al composites nano-al2o3 particles PRoPERTIES MICRoSTRUCTURE
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Effects of Y_2O_3 on Thermal Shock of Al_2O_3/TiCN Composites 被引量:3
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作者 邱关明 李喜坤 +3 位作者 修稚萌 孙旭东 严长浩 代少俊 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第3期266-270,共5页
Thermal shock resistance of Al2O3-TiCN(30%)-Y2O3(0.2%) composite was studied by hot pressing(HP) method at different temperatures. The study shows that thermal shock resistance of the material is determined by its mic... Thermal shock resistance of Al2O3-TiCN(30%)-Y2O3(0.2%) composite was studied by hot pressing(HP) method at different temperatures. The study shows that thermal shock resistance of the material is determined by its microstructure and reinforced mechanism. According to SEM and calculation of thermal shock, the fractured surface of Al2O3-30%TiCN-0.2%Y2O3 composite is undulate. The residual strength of Al2O3-30%TiCN-0.2%Y2O3 is higher than Al2O3-30%TiCN at 200~800 ℃ after thermal shock. Cracks initiation resistance (R′)and cracks propagation resistance (R″″)of Al2O3-30%TiCN-0.2%Y2O3 composite increases 12% and 5% respectively compared with that of Al2O3-30%TiCN. It matches with experimental results. The addition of Y2O3 forms YAG that inhibits crystal growth, and increases fracture stress, fracture toughness, cracks initiation resistance and cracks propagation resistance. Therefore, thermal shock resistance increases. The fracture work of Al2O3-30%TiCN and Al2O3-30%TiCN-0.2%Y2O3 composites are 132 and 148 J·m-2 respectively. 展开更多
关键词 composite al2o3-30%TiCN-0.2%Y2o3 thermal shock bending strength work of fracture rare earths
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