高熵合金Al5Co22.5Cu25Mn22.5Ni25微观组织与力学性能研究

摘要

为了得到一种高塑性的高熵合金,设计了一种新型高熵合金Al5Co22.5Cu25 Mn22.5Ni25,分析了高熵合金Al5Co22.5Cu25 Mn22.5Ni25的微观组织与力学性能,采用真空电弧熔炼炉制备出Al5Co22.5Cu25Mn22.5Ni25高熵合金,分析了其铸态和均匀化后的金相显微组织和晶体结构,测试了维氏硬度和室温拉伸性能.研究结果表明:高熵合金Al5Co22.5Cu25Mn22.5Ni25为面心立方结构,其铸态组织为典型的较发达树枝晶,晶粒尺寸大约为212 μm;均匀化处理工艺为1 000℃保温24 h随炉冷却,经过均匀化处理后,树枝晶转变为等轴晶.Al5Co22.5Cu25Mn22.5Ni25高熵合金均匀化处理后,屈服强度为282 MPa,抗拉强度为483 MPa,伸长率为52.68％,断裂类型为微孔聚集型穿晶断裂.均匀化处理前后合金的硬度分别为165.03 HV和177.9 HV.%In order to obtain a higher ductile high-entropy alloy,a new type of HEA,which was Al5 Co22.5Cu25Mn22.5Ni25 alloy,was designed.The microstructure and mechanical properties of Al5Co22.5Cu25Mn22.5Ni25 high-entropy alloy was analyzed.The HEA of Al5 Co22.5Cu25Mn22.5Ni25 was prepared by vacuum arc furnace,and the as-cast and annealed microstructure and crystal structure were analyzed.Vickers-hardness and room temperature tensile mechanical properties of Al5Co22.5Cu25Mn22.5Ni25 high-entropy alloy were studied.The results show that the Al5Co22.5Cu25Mn22.5Ni25 high-entropy alloy is with a face-centered cubic lattice structure and the as-cast microstructure of the alloy is typical dendritic and the gain size is approximately 212μm.Homogenization of the alloy was carried out at 1 000 ℃ for 24 h.Vickers-hardness is 163.05 HV and 177.9 HV,respectively after as-cast and annealing.Yield strength and tensile strength are 282 MPa and 483 MPa,respectively.The Al5Co22.5Cu25Mn22.5Ni25 high-entropy alloy has higher ductility with the elongation 52.68％ and it is transgranular microporous fracture.