Influence of observation plane on twin variant identification in magnesium via trace and misorientation analysis

{10−12}〈10−11〉 twinning plays an important role in plasticity of Mg alloys. Therefore, the reliable identification of twin variant is necessary for understanding the deformation mechanism of Mg alloys. This work aims to investigate the influence of observation plane on the identification of twin variant by twin plane trace and misorientation analysis using the electron backscatter diffraction technique. The twin characteristics in compression of a basal textured AZ31 alloy were examined on two different observation planes. The results indicate that the two geometrically favorable twin variants always have a low angle between their traces on the plane perpendicular to the c-axis, while a high angle range of 79–86° on the plane parallel to the c-axis and compression direction. Such high trace angle in the latter case makes it easy to unambiguously identify the active twin variant. Moreover, the reliability of variant identification is not affected by the number of activated twin variants and their misorientations. Further analysis indicates that the optimum observation plane on rolled and extruded Mg alloys is always the plane parallel to the c-axis and compression direction.