热处理对双FCC相CoCrFeNiCu高熵合金组织与性能的影响

用真空感应熔炼法制备了CoCrFeNiCu高熵合金,研究了不同退火温度对合金组织及力学性能的影响。结果表明,铸态CoCrFeNiCu合金具有双FCC相结构,分别为富Cu相和贫Cu相,而且相分离现象随热处理温度的升高逐渐明显。铸态合金的组织形貌为典型树枝晶组织,随热处理温度的升高,富铜相增多,枝晶间隙变宽,且出现了大量纳米颗粒。经600 ℃退火处理后,合金的屈服强度和断裂强度显著提高,屈服强度达到233 MPa,断裂强度接近铸态合金的3倍,并且伸长率无明显降低。

Effect of heat treatment on microstructure and properties of dual FCC-phase CoCrFeNiCu high entropy alloy

CoCrFeNiCu high entropy alloy was prepared by vacuum induction melting,and the effects of different annealing temperatures on microstructure and mechanical properties were studied.The results show that the as-cast CoCrFeNiCu alloy has a dual FCC-phase crystal structure,which are copper-rich phase and copper-dilute phase,respectively.The phase separation is gradually obvious as the heat treatment temperature increases.The microstructure of the as-cast alloy is a typical dendritic structure,and as the heat treatment temperature increases,the copper-rich phase increases,and the interdendritic region becomes wider,in which a large number of nanoparticles are precipitated.After heat treatment at 600℃,the yield and fracture strength of Co Cr Fe Ni Cu alloy are significantly improved,the yield strength reaches 233 MPa,and the fracture strength is close to 3 times of the as-cast alloy,however,the elongation of the alloy is basically unchanged.