Forming Limit Diagram Analysis Based On Crystal Plasticity for Magnesium Alloy Sheets

In the sheet metal forming industry, forming limit diagram (FLD) is a useful tool for quantifying metals formability. However, the experimental measurement of FLD is difficulty, time consuming and expensive process. It would be useful if FLD calculated with a theoretical model could replace experimental measurements. In this research, a rate independent crystal plasticity model is developed to analyze the plastic deformation of hexagonal close packed (HCP) materials by incorporating the crystallography of deformation twinning in plasticity model. The numerical simulations of FLD for AZ31 magnesium alloy are performed based on the crystal plasticity model incorporated within the Marciniak-Kuczynski (M-K) approach. The approach allows for the incorporation of initial texture, evolution of texture, and texture-induced anisotropy. The effects of mechanical twinning on plastic deformation and FLD behavior for AZ31 alloy are also incorporated. Finally, the calculation of the FLD for AZ31 alloy successfully predicts the experimental tendency that phenomenological plasticity model cannot reproduce.