Effect of Annealing Treatment on the Heterogeneous Microstructure and Properties of Cold-Rolled FeCoCrNiMn High-Entropy Alloy

The cold rolling and annealing treatment were applied to the face-centered cubic FeCoCrNiMn high-entropy alloy (HEA). The study investigated the heterogeneous microstructure and mechanical properties of FeCoCrNiMn HEA under different annealing temperatures and rolling reduction amounts. The results show that, when annealed at 600 degree celsius - 700 degree celsius, it is beneficial for obtaining a heterogeneous microstructure composed of fine grains, deformed grains and precipitated phases. Due to the multiple strengthening mechanisms caused by the heterogeneous microstructure, the FeCoCrNiMn HEA exhibits excellent tensile properties, achieving a better balance of strength and plasticity. With a primary rolling and annealing treatment at 650 degree celsius for 1 h, the recrystallization volume fraction is 50%, and the yield strength, ultimate tensile strength and elongation are 730.66 MPa, 909.67 MPa and 23.60% respectively, indicating high strength and ductility. With the increase of the annealing temperature, the precipitation of Cr-rich sigma phase becomes more evident, the maximum volume fraction of sigma phase is 1.96%, and the yield strength is increase by 41.65 MPa due to precipitation strengthening. With the increase of the degree of recrystallization, a phenomenon of texture component weakening and texture randomization occurs, but the main rolling textures, such as P-type and B-type textures, are still retained.