Significance of control of austenite stability and three-stage work-hardening behavior of an ultrahigh strength–high ductility combination transformation-induced plasticity steel

In the context of obtaining high strength-high ductility combination in transformation-induced plasticity steels, we underscore the practical significance of controlling the stability of austenite during deformation such that strain hardening induced by martensite transformation occurs at a critical strain. An optimized intercritical hardening at 750 °C led to a ferrite–austenite microstructure that was characterized by ∼64% austenite and excellent combination of tensile strength of ∼1000 MPa and elongation of ∼65%, and a three-stage work hardening behavior.