Phase reversion-induced heterogeneous structure in a ferrous medium-entropy alloy via cryorolling and annealing

A processing route via cryorolling and annealing is introduced to obtain heterogeneous grain structures in a Cr15Fe55Mn20Ni10 ferrous medium-entropy alloy (FeMEA). The cryorolled FeMEA consists of high-density shear bands, deformation-induced martensite, and residual matrix structure. After short-time annealing, the heterogeneous microstructure with multi-scale grains is formed in cryorolled sheets through phase reversion and partial recrystallization, which exhibits higher yield strength (477 MPa) and fracture elongation (44.3%) compared to room-temperature rolled sheets (389 MPa and 43.9%). The better combination of strength and ductility is due to grain boundary hardening, hetero-deformation-induced hardening, and dislocation hardening.