A Critical Review on Medium‐Mn Steels: Mechanical Properties Governed by Microstructural Morphology

Medium‐Mn steels have received significant attention from the steel industry as strong candidate materials for next‐generation advanced high‐strength steels. These steels can be manufactured by various routes, such as hot rolling plus annealing or cold rolling plus annealing, resulting in two different microstructural morphologies: laminate morphology or globular morphology with two‐phase microstructures. The resulting change in the microstructural morphology leads to a significant difference in the mechanical responses. For example, steel with a globular structure exhibits improved strength, toughness, and hydrogen embrittlement resistance compared to steel with a laminate morphology. The present review systematically summarizes the relationship between microstructural morphology and various mechanical responses to derive the optimal microstructural design concept for improved mechanical properties.