Effect of room temperature rolling and annealing on microstructure and mechanical properties of (CrCoNi)96V4 medium entropy alloy

Abstract

As cast (CrCoNi)96V4 medium entropy alloy（MEA）was prepared by vacuum arc melting. The MEA is deformed by rolling at room temperature with a total deformation of 67 %, The yield strength and tensile strength of the deformed MEA are 1297 MPa and 1410 MPa respectively, the elongation of the alloy is only 8 %.Then the deformed MEA was annealed for 30min at 700 °C, 800 °C and 900 °C respectively. The results show that the strength and ductility of the MEA after annealing were well balanced. The yield strength and tensile strength of the MEA after annealing at 900 °C/30 min are 678 MPa and 1024 MPa, and the elongation is maintained at 26 %. After annealing, a large number of annealing twins were formed in the MEA, which makes the strength and ductility of the MEA significantly improved. At the same time, Cr-rich particles were found in the MEA, which had positive effect on the improvement of the strength and ductility of the alloy.