热处理对CoCrFeNiMo高熵合金组织与硬度的影响

Effect of heat treatment on microstructure and hardness of CoCrFeNiMo high entropy alloy

用真空电弧熔炼法制备了CoCrFeNiMo高熵合金,研究了退火温度对合金组织及硬度的影响。结果表明,铸态合金的晶体结构以FCC为主,同时夹杂Cr_9Mo_(21)Ni_(20)和CrFe_4少量金属间化合物;铸态合金组织形貌为树枝晶,在枝晶间分布着类似于共晶组织的片层状结构,随退火温度升高,合金中FCC相逐渐减少,共晶相逐渐增多,最终形成了类似于过共晶的组织形貌;合金的硬度随退火温度的升高先增大后减小,但铸态与退火态的合金的硬度相差不大,说明此合金具有较高的热稳定性以及较好的高温使用性能。

CoCrFeNiMo high entropy alloy was prepared by vacuum arc melting.The effects of heat treatment on microstructure and hardness of the alloy were investigated.The results show that the crystal structure of as-cast alloy is mainly composed of FCC and a little Cr_9Mo_（21）Ni_（20） and CrFe_4 intermetallic compounds.Microstructure of the as-cast alloy shows dendritic structure with lamellar eutectic structure in interdendritic region.With the rising of annealing temperature,the amount of FCC phase gradually decreases,while the eutectic phase increases.The hardness of the alloy increases first and then decreases with the increase of annealing temperature.However,there is little difference in hardness between the as-cast and annealed alloys,which indicates that the CoCrFeNiMo high entropy alloy has high thermal stability and good high temperature application.