Fine-grained CoCrFeNiMn high-entropy alloy was prepared by underwater friction stir processing(UFSP)technology.The mi-crostructure and mechanical properties of fine-grained CoCrFeNiMn high-entropy alloy were studied.The results show that the average grain size of CoCrFeNiMn high-entropy alloy sample is refined from 110 pm of base metal to 2.6 µm after UFSP treatment.A large num-ber of twins occur in fine grains,and a small amount of BCC phase is percipitated along grain boundary.The grain refinement and precip-itation of BCC phase promote the average microhardness from 150 HV to 310 HV and tensile strength from 349 MPa to 938 MPa of the fine-grained CoCrFeNiMn high-entropy alloy,which reaches 206％and 269％of base metal,respectively.At the same time,twin coordi-nates the uniform distribution of stress of sample during tensile deformation and alleviates the occurrence of stress concentration.There-fore,fine-grained CoCrFeNiMn high-entropy alloy exhibits good elongation.
维普
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