中文摘要：

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Al_5Co_（22.5）Cu_（25）Mn_（22.5）Ni_（25）,分析了高熵合金Al_5Co_（22.5）Cu_（25）Mn_（22.5）Ni_（25）的微观组织与力学性能,采用真空电弧熔炼炉制备出Al_5Co_（22.5）Cu_（25）Mn_（22.5）Ni_（25）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Al_5Co_（22.5）Cu_（25）Mn_（22.5）Ni_（25）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212μm;均匀化处理工艺为1 000℃保温24h随炉冷却,经过均匀化处理后,树枝晶转变为等轴晶.Al_5Co_（22.5）Cu_（25）Mn_（22.5）Ni_（25）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177.9HV.

英文摘要：

In order to obtain a higher ductile high-entropy alloy,a new type of HEA ,which was Al5Co22.5Cu25Mn22.5Ni25 alloy, was designed. The microstructure and mechanical properties of Al5Co22.5Cu25Mn22.5Ni25 high-entropy alloy was analyzed. The HEA of Al5Co22.5Cu25Mn22.5Ni25 was prepared by vacuum arc furnace, and the as-cast and annealed mierostructure 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 212 μm. 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 Al5Co22.5Cu25Mn22.5Ni25s high-entropy alloy has higher ductility with the elongation 52.68% and it is transgranular microporous fracture.