Twinning-induced anomaly in the yield surface of highly textured Mg-3Al-1Zn plate

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 exhibits 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. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.