A cyclic kinematic hardening model magnesium sheet alloys at room temperature

• 1、School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, 200240 Shanghai, PR China

Abstract：A kinematic hardening constitutive model is presented, in which a simplified CPB06 yield criterion is adopted, and the initial asymmetric tension and compression yield stresses of magnesium (Mg) alloys at room temperature (RT) are considered. The hardening behavior was classified into slip, twinning, and untwinning deformation modes, and these were described by two forms of back stress to capture the mechanical response of Mg sheet alloys under cyclic loading tests at RT. Experimental values were obtained for AZ31B-O and AZ31B sheet alloys under both tension-compression-tension (T-C-T) and compression-tension (C-T) loadings to calibrate the parameters of back stresses in the proposed model. The predicted parameters of back stresses in the twinning and untwinning modes were expressed as a cubic polynomial. The predicted curves based on these parameters showed good agreement with the tests.

Keywords： Kinematic hardening Magnesium alloys sheet Back stress Twinning/untwinning Yielding asymmetry