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. (C) 2008 Elsevier B.V. All rights reserved.