The role of monotonic pre-deformation on the fatigue performance of a high-manganese austenitic TWIP steel

The fatigue performance of a high-manganese austenitic steel featuring the twinning-induced plasticity (TWIP) effect was investigated in both thermomechanically treated rolled and pre-deformed conditions. A thorough set of mechanical experiments and microstructural analyses demonstrated that microstructural evolutions during high-strain monotonic and low-strain cyclic deformations differ significantly. Specifically, a high twin density is obtained as a result of monotonic deformation, and a low twin density, yet a noticeable increase in twin thickness, is observed in the fatigued samples. Furthermore, the fatigue performance of the pre-deformed TWIP steel samples is superior to that of the as-received steel, which is attributed to the enhanced interaction of glide dislocations with twins of increased density owing to the monotonic pre-deformation. (C) 2008 Elsevier B.V. All rights reserved.