Investigation on the microstructural evolution and mechanical properties of partially recrystallized Fe-27Mn-10Al-1.4C steel

Fe-Mn-Al-C high-manganese steels with a combination of good strength and ductility are required in industrial applications. Herein, Fe-27Mn-10Al-1.4C (wt.%) lightweight steels with excellent strength and ductility were developed by cold rolling and subsequent annealing treatment. A bimodal microstructure consisting of partially recrystallized austenite (fine-sized recrystallized austenite grains and non-recrystallized austenite grains containing pre-retained dislocations) and nano-sized κ-carbide was formed after annealing. The as-prepared steel specimen exhibited superior mechanical properties including an ultimate tensile strength of 1387 MPa and a total elongation of 35%, which were attributed to the synergistic effect between recrystallization-induced softening and κ-carbide precipitation. Moreover, the strengthening effect of nano-sized κ-carbide and different precipitation behaviors in recrystallized and non-recrystallized regions were discussed.