The effects of Al 2O 3 fiber on wear characteristics of eutectic Al-Si alloy composites were studied using a pin-on-disk tester under dry sliding condition. The results show that the Al 2O 3 fiber can make matrix grai...The effects of Al 2O 3 fiber on wear characteristics of eutectic Al-Si alloy composites were studied using a pin-on-disk tester under dry sliding condition. The results show that the Al 2O 3 fiber can make matrix grain be fine, specially the eutectic Si be finer and prevent the plastic flow of matrix and prohibit the crack propagation in the wear layer, thereby it can remarkably improve the mechanical property and the wear resistance of the MMCs. Since Al 2O 3 fiber plays a role of certain framework in protecting the matrix against crash, it can eliminate the severe wear of MMCs with higher φ f of fiber from the beginning of test. At mild stage, when φ f is in the range of 8%～10%, the wear rates are the lowest. With increasing φ f of Al 2O 3 fiber, the wear mechanism of MMCs can be transformed from adhesive delamination to brittle breakaway.展开更多
A Ti(Al,Si)3 diffusion coating was prepared on γ-TiAl alloy by cold sprayed Al?20Si alloy coating, followed by a heat-treatment. The isothermal and cyclic oxidation tests were conducted at 900 °C for 1000 h and ...A Ti(Al,Si)3 diffusion coating was prepared on γ-TiAl alloy by cold sprayed Al?20Si alloy coating, followed by a heat-treatment. The isothermal and cyclic oxidation tests were conducted at 900 °C for 1000 h and 120 cycles to check the oxidation resistance of the coating. The microstructure and phase transformation of the coating before and after the oxidation were studied by SEM, XRD and EPMA. The results indicate that the diffusion coating shows good oxidation resistance. The mass gain of the diffusion coating is only a quarter of that of bare alloy. After oxidation, the diffusion coating is degraded into three layers: an inner TiAl2 layer, a two-phase intermediate layer composed of a Ti(Al,Si)3 matrix and Si-rich precipitates, and a porous layer because of the inter-diffusion between the coating and substrate.展开更多
对利用原位反应与高剪切液态搅拌复合专利技术制备的Al3Ti TiB2SiC/Al13%Si复合材料的增强相的形成热力学进行了理论计算和分析,并采用差热分析法(DTA)进行了试验验证。研究表明:(1)Al Ti B体系加入到Al13%Si熔体中可发生原位反应,形成...对利用原位反应与高剪切液态搅拌复合专利技术制备的Al3Ti TiB2SiC/Al13%Si复合材料的增强相的形成热力学进行了理论计算和分析,并采用差热分析法(DTA)进行了试验验证。研究表明:(1)Al Ti B体系加入到Al13%Si熔体中可发生原位反应,形成增强相,原位反应的开始温度为905.3℃,结束温度为1061.23℃;(2)Al Ti B体系加入到Al13%Si熔体中,制备颗粒增强Al13%Si复合材料的增强相为TiB2和Al3Ti,但TiB2形成能力最强。展开更多
文摘The effects of Al 2O 3 fiber on wear characteristics of eutectic Al-Si alloy composites were studied using a pin-on-disk tester under dry sliding condition. The results show that the Al 2O 3 fiber can make matrix grain be fine, specially the eutectic Si be finer and prevent the plastic flow of matrix and prohibit the crack propagation in the wear layer, thereby it can remarkably improve the mechanical property and the wear resistance of the MMCs. Since Al 2O 3 fiber plays a role of certain framework in protecting the matrix against crash, it can eliminate the severe wear of MMCs with higher φ f of fiber from the beginning of test. At mild stage, when φ f is in the range of 8%～10%, the wear rates are the lowest. With increasing φ f of Al 2O 3 fiber, the wear mechanism of MMCs can be transformed from adhesive delamination to brittle breakaway.
基金Project(50971127)supported by the National Natural Science Foundation of China
文摘A Ti(Al,Si)3 diffusion coating was prepared on γ-TiAl alloy by cold sprayed Al?20Si alloy coating, followed by a heat-treatment. The isothermal and cyclic oxidation tests were conducted at 900 °C for 1000 h and 120 cycles to check the oxidation resistance of the coating. The microstructure and phase transformation of the coating before and after the oxidation were studied by SEM, XRD and EPMA. The results indicate that the diffusion coating shows good oxidation resistance. The mass gain of the diffusion coating is only a quarter of that of bare alloy. After oxidation, the diffusion coating is degraded into three layers: an inner TiAl2 layer, a two-phase intermediate layer composed of a Ti(Al,Si)3 matrix and Si-rich precipitates, and a porous layer because of the inter-diffusion between the coating and substrate.
文摘对利用原位反应与高剪切液态搅拌复合专利技术制备的Al3Ti TiB2SiC/Al13%Si复合材料的增强相的形成热力学进行了理论计算和分析,并采用差热分析法(DTA)进行了试验验证。研究表明:(1)Al Ti B体系加入到Al13%Si熔体中可发生原位反应,形成增强相,原位反应的开始温度为905.3℃,结束温度为1061.23℃;(2)Al Ti B体系加入到Al13%Si熔体中,制备颗粒增强Al13%Si复合材料的增强相为TiB2和Al3Ti,但TiB2形成能力最强。
