Anisotropic Mechanical Behaviors and Constitutive Model of AZ31 Magnesium Alloy Sheets

Compared with traditional metal materials, the advantages of magnesium alloys are high specific strength and high specific stiffness, which are widely used in various fields of industrial production. The rolling magnesium alloy material has relatively complex mechanical properties due to its crystal structure and texture from processing. Uniaxial quasi-static tensile tests with five orientations along the rolling direction were designed based on the macroscopic elastic-plasticity theory to investigate the mechanical properties of AZ31 magnesium alloy sheets. Experimental true stress-strain and the plastic strain ratio were obtained by the DIC strain-measurement method, the initial yield strength decreases as the angle increases from 0 to 90°, while the tensile strength, in contrast, increases overall as the angle increases. The anisotropic yield criterion and plastic potential function were established in the basic form of the Hill48 yield function. The composite linear-swift hardening model was constructed according to the hardening characteristics of the material. Besides, the complete constitutive model was obtained by calibrating the parameters in the function with the experimental results. The anisotropic model was further validated based on the commercial finite element software COMOSL. The experimental results were compared to confirm the validity of the anisotropic model of AZ31 magnesium alloy sheets.