Ni3Al对CoCrFeNi高熵合金组织与性能的影响  

Effect of Ni3Al on Microstructure and Properties of CoCrFeNi High Entropy Alloy

作　　者：栾高灿 高鹏[1] 董可伟 刘祥奎 孔见[1] LUAN Gaocan;GAO Peng;DONG Kewei;LIU Xiangkui;KONG Jian(School of Materials Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学材料科学与工程学院,南京210094

出　　处：《有色金属工程》2020年第11期41-46,共6页Nonferrous Metals Engineering

摘　　要：设计了CoCrFeNi(Ni3Al)x(x=0.5、0.75、1、1.25)系列高熵合金,研究了合金的组织与性能,最后从热力学角度分析了不同相的形成原因。研究发现四种合金铸态时均为单相FCC固溶体。其中,铸态CoCrFeNi(Ni3Al)1.25具有最好的综合性能,屈服强度、抗拉强度、延伸率分别为420 MPa、867 MPa、21%。铸态合金经780℃、4 h时效处理后,枝晶间析出大量40~50 nm的L12相,时效后,CoCrFeNi(Ni3Al)1合金时效后具有最好的综合性能,屈服强度、抗拉强度、延伸率分别为530 MPa、828 MPa、22%。研究表明Ni3Al含量的添加和L12相的析出在适当范围内能够有效提高材料的强度,铸态时主要的强化方式是固溶强化,时效态主要是起析出强化作用。A series of high-entropy alloys of CoCrFeNi(Ni3Al)x(x=0.5,0.75,1,1.25)are designed.The microstructure and properties of the alloys are studied.Finally,the reasons for the formation of different phases are analyzed thermodynamically.It is found that the four alloys are all single-phase FCC solid solutions in the as-cast state.Among them,as-cast CoCrFeNi(Ni3Al)1.25 has the optimal comprehensive properties,yield strength,tensile strength,and elongation are 420 MPa,867 MPa,and 21%,respectively.After aging at 780℃for 4 h,a large amount of L12 phase of 40—50 nm precipitates between dendrites.After aging,CoCrFeNi(Ni3Al)1 alloy has the optimal comprehensive properties after aging,yield strength,tensile strength,and elongation are 510 MPa,828 MPa and 22%,respectively.Studies have shown that the addition of Ni3Al can effectively improve the strength of the material within the appropriate range.The main strengthening method in the as-cast state is solid solution strengthening,and the aging state mainly plays the role of precipitation strengthening.

关 键 词：高熵合金 析出强化 力学性能 面心立方 

分 类 号：TG113.251[金属学及工艺—物理冶金]