Texture-based forming limit prediction for Mg sheet alloys ZE10 and AZ31

Abstract

A viscoplastic self-consistent crystal plasticity model was employed to study the formability of two magnesium sheet alloys, i.e., AZ31 and ZE10 at 200 °C. The flow stress-strain curves obtained by uniaxial tension tests at various strain rates and the crystallographic texture obtained from X-ray diffraction were used to calibrate the model. The crystal plasticity model was incorporated with the Marciniak–Kuczyński model in order to address the forming limits of the magnesium sheets. A good agreement of the model predictions with the experimental data obtained by Nakajima tests was achieved. The model was further studied to quantify the effects of the sample orientation with respect to laboratory axes, the amount of pre-strain applied to the sheet prior to forming, and the initial crystallographic texture. The resulting forming limit diagrams demonstrate the optimal choice of sample orientation and crystallographic texture that can lead to a significant improvement in forming limit strains.