A Novel Cold-Rolled Medium Mn Steel with an Ultra-High Product of Tensile Strength and Elongation

A novel cold-rolled medium Mn steel (MMnS), 9Mn-0.3C-2Al(9Mn), was designed and studied in this work. The tensile strength and total elongation are up to 1073 MPa and 76%, respectively. Such an excellent mechanical properties are due to the presence of a large amount of meta-stable austenite having moderate stability and proper stacking fault energy. During the early stage of deformation, a considerable amount of deformation twins occured, leading to the resultant higher WHR; at the middle and late stages of straining, a continuous TRIP effect lasted in a wider strain range, leading to the delayed necking. (C) 2019 Elsevier B.V. All rights reserved.