Enhanced strength–ductility synergy in Fe 40 Ni 20 Co 20 Cr 20 high-entropy alloys by a heterogeneous grain structure

Abstract

In this study, we prepared a partially recrystallized heterogeneous grain structure (HGS) in Fe₄₀Ni₂₀Co₂₀Cr₂₀ high-entropy alloy via thermomechanical treatment. The HGS contained recrystallized grains (RGs) and non-recrystallized grains (NRGs), with a recrystallization ratio of 39.4% and an average grain size of 1.88 μm. During tensile deformation, heterogeneous deformation-induced strengthening occurred, and dislocations continuously accumulated at RG–NRG interfaces, strengthening the alloy via dislocation interactions. This structure significantly improved the strength of the HEA, yielding a tensile strength of 820 MPa and uniform elongation of 15.7%. The HGS optimized the strength–ductility balance, providing a reference for developing high-performance HEAs.