Superior strength-ductility synergy of FeMnCrNiAlSi high entropy alloy with heterogeneous structures

Alloys with excellent strength-ductility synergy and cost-effective performance have always been the pursuit of materials for engineering applications. In this study, Fe40Mn20Cr10Ni20Al5Si5 (at%) dual-phase high-entropy alloy with tensile strength of 1060 MPa and elongation of 26 % was developed. The precipitated Ni(Al, Mn) B2 phase was selected to strengthen the alloy, and the combination of soft and hard phases provides a strong workhardening capability. The dual heterogeneous structure, consisting of partially recrystallized and precipitated phases, overcomes the strength and plasticity trade-off at room temperature. For the heterogeneous structures, the mixing law is applied to calculate the flow stress, revealing additional strengthening components from dislocation hardening, precipitation hardening, and back-stress hardening. Our results demonstrate the possibility of synergistic enhancement of mutually exclusive properties such as strength-plasticity of alloys through nano-precipitation and heterostructures, providing new insights into the preparation of high-strength and highplasticity alloys.