Regulation of microstructure and deformation mechanism in heterogeneous austenitic cold-rolled medium manganese steel

This study selects Fe-0.32C-11.4Mn-3.3Al (wt.%) alloy as the research material and applies the IA-Q&P heat treatment process to explore the modulation effect of partitioning temperature on the mechanical properties, microstructure and deformation mechanism of the tested steel.The results show that the austenite content of the material reaches over 95% after heat treatment. The grains exhibit inhomogeneous characteristics, mainly presenting coarse lath, block and granular morphologies. During tensile deformation, synergistic actions of TRIP, TWIP and MBIP are activated, which contributes to superior post-fracture performance. The tested steel achieves a tensile strength of 1480 MPa and an elongation of 48%.This research provides new insights and experimental support for microstructure regulation and multi-mechanism synergistic deformation of austenitic medium-Mn steel.