AlCoCrFeMnTi高熵合金的组织结构和耐磨性能研究

Research on Microstructure and Wear Resistance of AlCoCrFeMnTi High Entropy Alloy

采用真空电弧熔炼法制备出等摩尔比的Al CoCrFeMnTi多主元高熵合金。利用X射线衍射仪、光学显微镜、显微硬度计和摩擦磨损试验机测试了Al CoCrFeMnTi合金的物相结构、显微组织、硬度与耐磨性能。结果表明:Al CoCrFeMnTi合金是由BCC主相和FCC相构成的双相结构,其显微组织属于典型的树枝晶结构。铸锭底部区域显微组织较顶部区域明显偏小,是因为该区域散热快、过冷度大、形核率高,有利于从熔体中大量析出固相晶坯使其组织细化。Al CoCrFeMnTi显微硬度和摩擦系数分别为919.42 HV0.5和0.45,耐磨性能优异则是因为在凝固过程中形成了以高强BCC相为主的物相结构所致。

AICoCrFeMnTi multiprincipal high-entropy alloy with equal molar ratio was prepared by vacuum arc melting method.The phase structure,microstructure,microhardness and wear resistance of AICoCrFeMnTi alloy were investigated by X-ray diffractometer,optical microscope,microhardness tester and friction-wear tester.The results show that AiCoCrFeMnTi alloy is a dual-phase structure composed of BCC main phase and FCC phase,and its microstructure belongs to a typical dendrite structure.The microstructure of the bottom area in the ingot is obviously smaller than that of the topside area because of the fast heat dissipation,high undercooling degree and high nucleation rate,which is beneficial to the precipitation of a large number of solid billets from the melt and the refinement of the structure.The microhardness and friction coefficient of AICoCrFeMnTi is 919.42 HV0.5 and 0.45,respectively.The excellent wear resistance is due to the formation of phase structure dominated by high-strength BCC phase during solidification.