Deformation behavior of Mg–8Al magnesium alloy compressed at medium and high temperatures

Abstract

The mechanisms of plastic deformation of Mg–8Al magnesium alloy were studied by compression tests at temperatures between 250 and 450°C and strain rates ranging from 0.01 to 50s−1. It was found that the mechanisms of dynamic recrystallization depend on the deformation temperature. In the intermediate temperature range (250–300°C), continuous dynamic recrystallization was observed and associated with extensive cross slip. Coarse primary grains are replaced by the new fine grains with the progress of deformation, leading to a “necklace structure”. At temperatures ranging from 350°C to 450°C, the deformation was self-diffusion controlled. Equiaxed dynamic recrystallization grain structures are obtained during the whole deformation process. New dynamic recrystallization grains are preferred to nucleate in areas where extensive multiple slip bands have formed. Twinning plays an important role during the deformation of Mg–8Al magnesium alloy both at intermediate and high temperature ranges.