Enhanced plasticity mechanism of HPR-AZ31 magnesium alloy with dynamic recrystallization weakening basal texture intensity

In order to elucidate the influence of basal texture strength on the mechanical properties of sheet materials subjected to varying degrees of recrystallization, this study investigates the AZ31 magnesium alloy gradient structure sheets produced via Hard plate rolling (HPR). The research examines the dynamic recrystallization degree and basal texture intensity of the sheets at different deformation temperatures. The results reveal that AZ31 magnesium alloy sheets processed under three distinct deformation conditions exhibit gradient microstructural characteristics, with the most pronounced differences between coarse and fine grains observed in the HPR-350 process. Notably, the recrystallization degree of both the fine-grained (FG) and coarse-grained (CG) zones in the HPR-350 condition exceeds that of the HPR-300 and HPR-400 conditions, with the FG zone of HPR-350 achieving the highest recrystallization degree of 78.8 %. Due to the varying degrees of recrystallization, the texture intensity along the normal direction (ND) of the sheet shows significant differences. Specifically, at different temperatures, the texture intensity in the CG region is markedly greater than in the FG region, and the texture strength of non-recrystallized grains is significantly higher than that of recrystallized grains. Therefore, dynamic recrystallization weakens basal texture intensity. This reduction facilitates the activation of non-basal slip systems, thereby increasing the average Schmid factor. Among the conditions studied, the average value of each slip system in the HPR-350 process is the highest, indicating that dislocation slip occurs more readily in all directions, resulting in superior mechanical properties of the magnesium sheet at 350 °C. In conclusion, dynamic recrystallization contributes to the weakening of basal texture intensity, enhancing the plastic deformation capacity of the gradient structure magnesium alloy sheet and offering a novel approach for fabricating high-performance magnesium alloy gradient structure sheets.