Biaxial Deformation Behaviour of AZ31 Magnesium Alloy: Crystal-Plasticity-Based Prediction and Experimental Validation

Abstract

Plastic deformation of the commercial magnesium sheet alloy AZ31 under monotonic loadings has been investigated by means of mechanical tests and numerical simulations. Additionally to the commonly used uniaxial test two complementary mechanical tests have been performed: a biaxial test using cruciform specimens and a hydraulic bulge test. Both tests lead to consistent results and evidence the differential strain hardening character of the considered material. A polycrystalline aggregate has been generated from measured texture data. Simulations using the visco-plastic self consistent (VPSC) scheme indicate the primary role of pyramidal slip in equibiaxial tension. Contours of equal plastic work have been generated using a methodology based on probing the aggregate in space of principal strains. The contours were compared with respective tests. Hardening parameters have been fitted in order to capture initial yield and evolution of iso-work contours. Limitations of the numerical framework’s predictive capability as well as directions for parameter identification of phenomenological yield surfaces are formulated.