Enhanced strength and ductility in (CoCrNi)92Mo2Al6 medium entropy alloy via dual heterogeneous structures

Abstract

In the present (CoCrNi)92Mo2Al6 medium entropy alloy (MEA), a dual heterogeneous structure is achieved by regulating the degree of recrystallization of the FCC matrix and σ phase precipitation through incomplete annealing. Compared to the alloys with single-phase FCC structure or uniform precipitation structure, this dual heterostructured MEA has superior mechanical properties by possessing the hetero-deformation-induced (HDI) hardening, precipitation strengthening and twinning-induced plasticity (TWIP) mechanism. Our research contributes to the understanding of the micromechanical behavior of heterogeneous materials and also provides a solution to the problem that precipitation increases strength at the expense of plasticity.

Keywords

• Medium-entropy alloys
• σ phase
• heterogeneous structure
• mechanical properties