Low-cycle fatigue characteristics of rolled Mg-3Al-1Zn alloy

Fatigue characteristics of rolled Mg-3Al-1Zn (AZ31) alloy were investigated by performing the low-cycle fatigue test along the rolling direction. The alloy was found to have a strong basal texture so that the fatigue deformation was predominated by the alternation of twinning and detwinning during each cycle, and this made the cyclic stress response unstable and introduced a non-zero mean stress and/or strain depending on the loading condition. An energy-based concept was successfully used to predict the low-cycle fatigue life because a plastic strain energy density was found to have good characteristics as a fatigue parameter; it was stabilized at the early stage of fatigue life and nearly invariant through entire life. In the life prediction model, the effect of mean stress was appropriately considered. (C) 2010 Elsevier Ltd. All rights reserved.