本团队毕业生刘发美博士等在Journal of Magnesium and Alloys发表研究论文。

摘要：The poor room-temperature formability limits the widespread engineering application of magnesium alloy, necessitating hot deformation processes where damage evolution is critically influenced by microstructure. While the present damage models overlook the specific roles of dynamic recrystallization (DRX) and twinning, which are pivotal in magnesium alloys. Given this limitation, this study developed a microstructure-related Gurson-Tvergaard-Needleman (GTN) damage model for AZ31 alloy under high-temperature conditions. The model was calibrated based on uniaxial tension tests conducted at 300 °C, which revealed that DRX suppresses void initiation and growth, whereas twinning promotes shear damage. The modified model was subsequently applied to simulate the wedging spinning process. Comparisons between simulations and experiments confirmed the model’s reliability in predicting deformation, microstructure distribution, and damage. The analysis revealed that during early stage of the process, the DRX fraction is higher near the inner and outer surfaces of the conical wall and lower in the middle layer, whereas the twin volume fraction follows the opposite trend. In the later stage, DRX occurs throughout the entire conical wall while twinning is nearly completely consumed. The study identifies shear damage, correlated with equivalent strain, as the primary damage mechanism, while void evolution is influenced by fluctuations in stress triaxiality. Furthermore, it was found that excessively small spinning thicknesses and large dip angles exacerbate the risk of inner surface cracking. This established model proves to be effective for predicting damage and optimizing process parameters in the hot spinning of AZ31 alloys.