Substructure development, martensitic transformation and rapid work-hardening in an as-cast interstitial substituted N atom in FeMnCoCr high-entropy alloy

Abstract

The microstructural evolution and room-temperature mechanical properties of nitrogen-added Fe50Mn30Co10Cr10 as-cast high-entropy alloy were investigated. Interestingly, an excellent strength-ductility trade-off with a rapid hardening stage was achieved in the as-cast structure (tensile strength: 740 MPa, ductility: 42 %) that was comparable with those counterparts holding wrought structure. These excellent mechanical properties were attributed to the capability of metastable FCC microstructure enabling deformation-induced martensitic transformation even at low imposed strain at room temperature. Simultaneously, the occurrence of substructure development independent of martensitic transformation, significantly contribute to increase the capability of the material for strain accommodation.