Effects of Rolling and Annealing on Microstructure and Mechanical Properties of FeCoCrNiN0.07 High-entropy Alloy
FeCoCrNiN007 high-entropy alloy(HEA)was prepared by the way of powder metallurgy hot isostatic pressing(HIP),and the effects of cold-rolled deformation and subsequent annealing at 750 ℃ on the microstructure and mechanical properties of FeCoCrNiN0.07 high-entropy alloy were studied.The results show that the HIPed FeCoCrNiN007 HEA has a simple single-phase FCC structure.The HIPed alloy has no second phase transformation after cold-rolled deformation and subsequent annealing at 750 ℃.The microstructure of the HIPed alloy is composed of a large number of equiaxed grains and annealing twins.After cold-rolled deformation,a large number of microscopic shear bands and some deformation twins are produced in the microstructure,and there are also lots of microscopic strains and high dislocation density.The cold-rolled alloy undergoes complete recrystallization after annealing at 750 ℃,and a large number of small equiaxed recrystallized grains and annealing twins are formed.The HIPed alloy exhibits excellent plasticity but low strength,after cold-rolling,the strength increases significantly but the plasticity is significantly reduced,which is mainly due to the effect of dislocation strengthening.After annealing at 750 ℃,the strength decreases and the plasticity increases,and the best comprehensive mechanical properties were obtained,the decrease in strength is due to the effect of recrystallization softening,and the higher strength than that of the HIPed state is due to the effect of fine-grain strengthening.
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