Twinning and double twinning upon compression of prismatic textures in an AM30 magnesium alloy

Twinning mechanisms in a {1 0 1¯ 0}-fiber texture of an AM30 magnesium alloy were studied under profuse and nominal {1 0 1¯ 2} twinning conditions produced by different compression orientations. While {1 0 1¯ 2} twins took the form of fully residual twins upon profuse conditions, they were “stopped elastic” twins upon nominal conditions. Profuse nucleation of {1 0 1¯ 1}–{1 0 1¯ 2} and {1 0 1¯ 3}–{1 0 1¯ 2} double twins occurred as a two-shear mode mechanism which substantiated Crocker’s theory of double twinning. These two double twinning modes played an important role in rushing sample fracture.