We study here the underlying factors that govern the stability of austenite in a medium Mn (Fe–0.18C–11Mn–3.8Al) (wt-%) steel. In this regard, a novel heat treatment involving intercritical quenching and tempering was designed to obtain high total elongation (TEL) and high ultimate tensile strength (UTS) in the cold-rolled steel. And the UTS and TEL approached 920–1150 MPa and 35–65%, respectively. The product of TEL and UTS (PSE) exceeded 40 GPa%, with a maximum value of 60 GPa%. A detailed analysis of microstructure before and after tensile deformation revealed that the TRIP effect occurred and the stability of austenite was predominantly governed by the grain sizes of austenite rather than the orientation of austenite grains. The theoretical analysis of work hardening data suggested that the superior elongation of medium Mn TRIP steel is related to the high stability of austenite and the cooperative deformation of ferrite.

我们在这里研究控制中等Mn（Fe–0.18C–11Mn–3.8Al）（wt％）钢中奥氏体稳定性的基本因素。在这方面，设计了一种包括临界淬火和回火的新型热处理，以在冷轧钢中获得高总伸长率（TEL）和高极限抗拉强度（UTS）。UTS和TEL分别达到920-1150 MPa和35-65％。TEL和UTS（PSE）的乘积超过40 GPa％，最大值为60 GPa％。对拉伸变形前后的微观结构进行的详细分析表明，发生了TRIP效应，奥氏体的稳定性主要受奥氏体晶粒尺寸的控制，而不是奥氏体晶粒的取向。