Initial grain size effect of dynamic recrystallization of magnesium alloy AZ31

Dynamic development of new grain boundaries was studied in compression of a magnesium alloy AZ31 with initial grain sizes (D-0) of 22 mum and 90 mum at a temperature of 673K. Kink bands are evolved near corrugated grain boundaries and in grain interiors at low strains accompanied with new fine grains. Kink bands are developed often perpendicular to the basal plane. The boundary misorientation of kink band as well as the volume fraction of new grains increases rapidly with increasing strain and approaches a saturation value in high strain. New fine grains are developed faster with decrease in the D-0. It is concluded that new grain evolution is controlled by a deformation-induced continuous reaction, i.e. continuous dynamic recrystallization (DRX).