STUDY OF TWIN BEHAVIOR DURING UNIAXIAL COMPRESSION OF AZ31 MAGNESIUM ALLOY

Abstract

The effect of inhomogeneous deformation on twinning behavior during uniaxial compression of AZ31 magnesium alloy at room temperature was investigated with electron backscattered diffraction (EBSD) technique. The evolution of twin area fraction in three locations, typical of a dead zone, an easy zone and a free zone with strain was analyzed. The results show that the twin area fractions at the locations in dead zone, easy zone and free zone are different at compression strains less than 8%. As compression strain reaches 8%, the area fraction of extension twins at these three locations is almost the same, and is about 90%. Inhomogeneous deformation exerts much effect on the twin area fraction at the locations in the three zones at low strains while exerts little effect at high strains. Twin variant selection in the three zones at 2% strain was also analyzed. The results show that the twin variant activation is governed by the Schmid factor criterion in all the three zones. However, the percentage of grains with two twin variant types in free zone is higher than that in dead zone and easy zone, due to the different stress states in this location.