The anisotropy of Mg alloy is investigated using uniaxial compression experiments. The anisotropic behaviors of interest include the texture, deformed shape, constitutive relationship, and fracture characteristics, and all of them are related to the microscopic mechanisms which include the competition between twinning and slipping at different temperatures and strain rates. When the loading is perpendicular to the c-axis of the HCP lattice, the specimen yields at a low stress because twinning is favored at relatively low strain, the deformed shape is strongly anisotropic owing to the slipping at high stress along 〈112̄3〉, and fracture occurs along 〈112̄3〉. On the other hand, when the loading is parallel to c-axis, there is no twinning process and the plastic deformation is dominated by slipping which requires higher stress, the yield stress is higher, and the deformation is isotropic. Anisotropy is also more prominent upon lower temperature or higher strain rate, largely thanks to twinning.
The work is supported by National Natural Science Foundation of China (50928601 and 50725413), 973 National Grand Theoretical Research Program of China (2007CB613700), International Cooperation Program (2010DFR50010, 2008DFR50040), Chongqing Sci & Tech Program (CSTC2009AB4008, 2010CSTC-HDLS), Changjiang Scholar Program from Ministry of Education of China, WCU (World Class University) program through the National Research Foundation of Korea (R32-2008-000-20042-0), DARPA (W91CRB11-C-0112), and National Science Foundation (CMMI-0643726).