Enhancing strength–ductility synergy in high-Mn steel by tuning stacking fault energy via precipitation

Abstract

Deformation-induced twinning or martensitic transformation can improve the work-hardening capability of alloys with face-centered cubic (FCC) structures and suppress strain localization. The stacking fault energy (SFE) of alloys plays a key role in determining deformation mechanisms and mechanical properties. This study developed V-bearing high-Mn steel with a tensile strength of 1288 MPa and uniform elongation of 36 % by tactfully designing the composition. Precipitation of V-carbides was selected to strengthen the steel and tune the global SFE of the matrix by settling carbon. Stronger work-hardening capability due to lower SFE and finer twin/matrix lamellae provided the steel with good ductility, while precipitation strengthened it.