Experimental study on the mechanical properties of AZ31B-H24 magnesium alloy sheets under various loading conditions

Abstract

In order to fully characterize the plasticity and fracture of magnesium AZ31B-H24 sheets, a set of mechanical experiments (105 in total) were performed under different loading conditions, including monotonic uniaxial tension, notch tension, in-plane uniaxial compression, wide compression (or called biaxial compression), plane strain compression, through-thickness compression, in-plane shear, punch test, and uniaxial compression–tension reverse loading. Both the plastic strain histories and stress responses were obtained under the above loading conditions, which give a comprehensive picture of mechanical behaviors of this material. An orthotropic yield criterion involving two linear anisotropic transformation tensors, CPB06ex2, in conjunction with its associated flow rule, and a modified semi-analytical Sachs isotropic hardening model was fully calibrated to describe both the anisotropy in plastic flow and tension–compression asymmetry in stress–strain behaviors. An all-strain based modified-Mohr–Coulomb fracture model, transformed from a stress triaxiality based model, was applied to describe the calibrated fracture locus. Applying a linear transformation to the plastic strain tensor, a non-conjugated anisotropic equivalent strain was proposed to characterize anisotropic fracture behaviors. Good correlations were achieved between experimental results and model predictions in terms of material yield strengths, strain hardening curves, plastic flow directions and ductile fracture strains.