The evolution of stress and lateral strains with applied strain was determined by uniaxial loading in the principal directions of a highly textured Mg–3Al–1Zn plate. The material exhibited negative lateral strain ratios when twinning dominates deformation. This leads to a yield surface with a distinct shape, with a high curvature under a balanced biaxial stress state and a shift in plane-strain compression conditions from the third to the second and fourth quadrants of the yield surface.

Twinning-Induced Anomaly in the Yield Surface of Highly Textured Mg–3Al–1Zn Plate. Y.B.Chun, C.H.J.Davies: Scripta Materialia, 2011, 64[10], 958-61