Effect of particles on the formation of deformation twins in a magnesium-based alloy

The deformation behaviour of the age hardenable alloy Mg-5%Zn after different precipitation treatments has been examined. It has been found that during compressive deformation, fine particles increase the number of twins that form, but reduce the size and total volume fraction of twins. Visco-plastic self-consistent modelling has been used to show that the presence of precipitates hardens the twin and prismatic slip systems more than the basal slip system. It is proposed that because the {101¯2} twin requires basal slip to accommodate the twinning shear, this twin type will always be hardened equal to, or more than, the basal slip system in response to precipitation.