Construction of High Strain Rate Loading Constitutive Model and Failure Model and Prediction of Forming Limit for LA103Z Magnesium Alloy

In order to use numerical simulation to reveal the formability of magnesium–lithium alloys and other light alloys under high strain rate, it is crucial to construct a constitutive model and a forming limit diagram (FLD) of LA103Z alloy that was formed by laser shock at high strain rate. In this study, three different uniaxial tensile experiments on the ultralight alloy material LA103Z magnesium alloy were conducted, the mechanical behavior of the material with sensitivity to high strain rate was studied, and a Johnson–Cook (JC) constitutive model sensitive to high strain rates and suitable for laser shock forming was proposed. At the same time, the constitutive parameters and failure parameters of the modified JC model of LA103Z magnesium alloy were obtained through three different uniaxial tensile experiments. On the basis of the relationship between tensile loading and stress–strain of LA103Z magnesium alloy, the experiments demonstrated the precision of the modified JC constitutive model. A modified constitutive model was then developed by using the user material subroutine VUMAT, and then it was applied to ABAQUS. Finally, the formability of the material was simulated, and the FLD of LA103Z magnesium alloy material in laser shock forming was predicted. This study provides guidance on the actual production and application of LA103Z magnesium alloys.