Austenite Tailoring for Strength and Ductility Enhancement in Medium Mn Steel: A Brief Review.

Over the past decades, intensive efforts have been dedicated to overcoming the strength-ductility trade-off dilemma of advanced high-strength steels by creating multi-phase microstructures with chemical heterogeneity. This paper presents a brief summary of the advancements in medium Mn steel (MMnS), which has garnered prominence in automobile applications due to its high strength coupled with good toughness achieved via the modulation of retained austenite (γ_ret) stability. We examine the optimization of integral mechanical attributes such as strength, ductility and toughness. MMnS can reach an ultimate tensile strength (UTS) beyond 2200 MPa; however, there is a steep decline in toughness below 100 J when the UTS is > 1200 MPa. The relevant mechanisms including novel alloying design strategies, innovative processing routines such as flash processing, chemical boundary engineering and meticulous modulation of γ stability through chemical heterogeneity are analyzed. Furthermore, the potential avenues for research and innovation in MMnS are outlined by incorporating laser additive manufacturing technologies. [ABSTRACT FROM AUTHOR]