The effects of thermomechanical training treatment on the deformation characteristics of Fe–Mn–Si–Al alloys

We have studied the effects of the thermomechanical training treatment on the deformation mode for Fe–30Mn–(6 − x)Si–xAl (x = 0, 1, 2 and 3 mass%) alloys, which exhibit complicated deformation processes due to coexistence of the stress-induced fcc to hcp martensitic transformation and the mechanical twinning of the fcc matrix in addition to slip deformation. The stress–strain curves at each training cycle were analyzed for the alloys, and the deformation microstructures were observed with atomic force microscopy on a Fe–30Mn–5Si–1Al alloy before and after the training treatment. It was found that the deformation mode shifts from the mechanical twinning to the stress-induced martensitic transformation, as the training proceeds.