Anelastic deformation during cyclic loading-unloading of die-cast magnesium alloys

The anelastic deformation of high-pressure die-cast Mg-4Al-0.3Mn (AM40) and Mg-4Al-4RE (AE44) is investigated over a quasi-static strain-rate range 10-6-10-1 s-1. It is observed that the anelastic strain increases with increasing strain until it reaches a steady state. The anelastic strain is less dependent on strain rate at the early stage of deformation; the anelastic strain becomes more strain-rate dependent beyond a total strain of 0.8% for the present alloys. Anelasticity is attributed to reversible twinning and since twinning is known to be independent of strain rate, strain rate is not expected to be an influencing factor for anelasticity. In this study, the strain-rate sensitivity of maximum anelasticity is attributed to the activation of non-basal slip and its influence on twinning.