AlCrNiFeTi高熵合金涂层的电火花沉积制备与摩擦磨损性能

Preparation and frictional wear property of AlCrNiFeTi high-entropy alloy coatings by electric spark deposition

采用真空电弧熔炼法制备直径为7 mm AlCrNiFeTi高熵合金(high-entropy alloy,HEA)作为电极,使用电火花沉积技术在304不锈钢表面成功制备了AlCrNiFeTi高熵合金涂层。通过XRD、OM、EDS、SEM、显微硬度计、摩擦磨损试验机对涂层的微观组织结构和摩擦磨损性能进行研究。结果表明,AlCrNiFeTi电极与涂层均以BCC1和BCC2简单固溶体为主,电极微观组织结构呈典型的树枝晶。涂层由沉积点堆叠铺展形成,表面均匀致密呈橘皮状、凸凹不平,为喷溅花样展开,涂层截面结构无宏观缺陷,厚度约为59.67μm。AlCrNiFeTi涂层最大显微硬度为587.3HV0.2,比基材的硬度提高了约2.45倍。随着载荷的增大,涂层的磨损机制由氧化磨损和轻微磨粒磨损转变为磨粒磨损和黏着磨损。当摩擦载荷为5 N时,磨损率为1.213×10^(-3)mm^(3)/(N·m),摩擦因数仅为0.446,涂层的磨损率较基材的磨损率减小了约28.3%。

AlCrNiFeTi high-entropy alloy(HEA)with a diameter of 7 mm was prepared as electrode by vacuum arc melting method,and AlCrNiFeTi high-entropy alloy coating was successfully prepared on the surface of 304 stainless steel by using electric spark deposition technology.The microstructure and friction and wear properties of the coatings were studied by XRD,OM,EDS,SEM,microhardness tester and friction and wear tester.The results show that both the AlCrNiFeTi electrode and the coating are dominated by BCC1 and BCC2 simple solid solutions,and the microstructure of the electrode is typical of dendrites.The coating is formed by stacking and spreading of deposition points,and the surface is uniform and dense as orange peel,convex and concave,unfolding for sputtering pattern,and there is no macroscopic defects in the coating cross-section structure,and the thickness is about 59.67μm.The maximal microhardness of AlCrNiFeTi coating is 587.3HV0.2,which is about 2.45 times higher than that of the base material.As the load increases,the wear mechanism of the coating changes from oxidized wear and slight abrasive wear to abrasive and adhesive wear.When the friction load is 5 N,the wear rate is 1.213×10^(-3) mm^(3)/(N·m),and the friction coefficient is only 0.446.The wear rate of the coating decreases by about 28.3%compared with that of the substrate.