The room-temperature tensile behavior of a high Mn-Al-C steel in the solid-solution state was correlated to the microstructures developed during plastic deformation in order to clarify the dominant deformation mechanisms. The steel was fully austenitic, with a stacking-fault energy of 85mJ/m2. The tensile behavior of the steel was characterised by an excellent combination of strength and ductility of over 80000MPa%; in association with continuous strain-hardening to high strains. The austenite phase was very stable during deformation. The high stacking-fault energy and stability of the austenite were attributed to the high Al content. In spite of the high stacking-fault energy, the deformed microstructures exhibited planar glide characteristics, apparently due to the glide-plane softening effect. During straining, the formation of crystallographic microbands and their intersection predominantly occurred. Microbands consisting of geometrically necessary dislocations led to a high total dislocation density state during deformation, resulting in continuous strain hardening.

Microband-Induced Plasticity in a High Mn-Al-C Light Steel. J.D.Yoo, K.T.Park: Materials Science and Engineering A, 2008, 496[1-2], 417-24