The deformation mechanisms of three TWIP steels in Fe-Mn-C system, with differing stacking-fault energies, were examined. The results showed that the microstructure was fully austenitic in the quenched state, with a few annealing twins in the matrix. With increasing C and Mn content, the stacking-fault energy of the TWIP steel increased. When the stacking-fault energy was equal to 7mJ/m2, there was a mass of ε-martensite in the TWIP steel after deformation, and the volume of ε-martensite increased with increasing strain. When the stacking-fault energy was equal to 12mJ/m2, strain-induced γ → ε → α or γ → α phase transformations plus a few mechanical twins were found. When the stacking-fault energy was equal to 18mJ/m2, a large number of mechanical twins formed after deformation, resulting in a higher tensile strength (up to 851MPa) and elongation (49%).

Influence of Stacking Fault Energy on Deformation Mechanism of Fe-Mn-CTRIP/TWIP Steels. J.S.Zeng, J.Xiong, W.Shi, L.Li: Material Science and Technology, 2013, 21[2], 72-6