Al0.2Co1.5CrFe1.2Ni1.5TiC0.4高熵合金的微观组织、力学与高温摩擦学性能

通过引入碳元素,设计了一种以原位形成的碳化物为增强相的高熵合金Al_(0.2)Co_(1.5)CrFe_(1.2)Ni_(1.5)TiC_(0.4),并采用放电等离子烧结(SPS)技术成功制备了这种高熵合金.采用XRD、SEM、EDS、万能材料试验机和高温摩擦磨损试验机等研究了微观组织、力学性能和室温至800℃下的摩擦学性能.结果表明:Al_(0.2)Co_(1.5)CrFe_(1.2)Ni_(1.5)TiC_(0.4)高熵合金由面心立方(FCC)结构的高熵固溶体基体相和弥散分布的TiC陶瓷相组成.FCC相使高熵合金具有良好的塑性和韧性,而TiC增强相赋予了高熵合金高的硬度和强度.随着温度的升高,高熵合金的摩擦系数和磨损率均具有逐渐减小的趋势.在800℃时,鉴于摩擦氧化作用,在磨损表面形成了致密的氧化物釉质层,起到了良好的减摩抗磨作用,使高熵合金表现出了优异的高温摩擦学性能.

Microstructure, Mechanical and Tribological Properties of Al0.2Co1.5CrFe1.2Ni1.5TiC0.4 High Entropy Alloy

Al0.2Co1.5CrFe1.2Ni1.5TiC0.4 high entropy alloy (HEA) was designed and then prepared by spark plasma sintering.Its microstructure,mechanical properties and tribological behaviors from room temperature to 800 ℃ were studied by X-ray diffractometer,scanning electron microscopy,energy dispersive spectroscopy,universal material testing machine,and high temperature tribometer.The results show that Al0.2Co1.5CrFe1.2Ni1.5TiC0.4 HEA was composed of high entropy solid solution matrix phase with face-centered cubic (FCC) crystal structure and dispersively distributed TiC ceramic phase in the matrix.Moreover,FCC phase rendered HEA excellent ductility and toughness.TiC strengthening phase made HEA high hardness and strength.With the increase of temperature,the friction coefficients and wear rates decreased.Because of tribo-oxidation,a dense oxide glaze layer was formed on the worn surface at 800 ℃,which played an importent role of friction reduction and wear resistance and made HEA excellent high temperature tribological behavior.