EBSD analysis of {10-12} twinning activity in Mg-3Al-1Zn alloy during compression

The {10-12} twinning activity of Mg-3Al-1Zn magnesium alloy during uniaxial compression at room temperature has been investigated by electron backscatter diffraction. The results indicated that the twinning activity was closely related with two angles: one was the angle between the c-axis and the compression direction and the other was the angle between the a-axis and the titling direction in the basal plane for a given relation between the c-axis and the compression direction. These two parameters can be used to explain which twinning variant will operate under the given strain path. For the grains containing a single {10-12} twinning variant, the {10-12} twinning variant occurred in a wide range of Schmid factor values (0 < Schmid factor < 0.5) and the Schmid factor rank of 1 or 2 was the most commonly observed. By contrast, for the grains containing two {10-12} twinning variants, the {10-12} twinning activity exhibited a stronger orientation dependence and the combinations of Schmid factor ranks 1-3 and 1-2 were the most commonly observed.