AZ31镁合金板材超塑性气胀成形研究

研究了AZ31镁合金板材不同工艺条件下的气胀成形性能。实验表明，胀形高度随温度的升高而增大，且应变速率敏感指数值均大于0.3。在673K,0．7MPa下胀形25min所得的胀形件胀形高度达23．34mm，高径比为0．67。由金相及SEM电镜观察可知，在胀形件的顶端晶界处聚集了大量空洞。通过动态再结晶，晶粒得到了很大细化。并且随变形程度的增大，晶粒细化更明显。AZ31镁合金板材的超塑性胀形主要由晶界滑移控制，动态再结晶则为重要的辅助机制。

Research on Superplastic Gas Bulging Forming of Magnesium Alloy AZ31

The superplastic gas bulging forming of a rolled magnesium alloy AZ31 at different temperature and gas pressure was researched. In the condition of 673 K, 0.7 MPa forming, the highest height is 23.34 mm,H/d=0.67. Optical microstructral observation and SEM observation shows that there are a lot of typical cavities in the grain boundary of the dome after superplastic deformation. The grain refinement after forming is obvious. The grain size in the big deformation area is much smaller. This is attributed to dynamically continuous recrystallization during forming. The most important forming theory is GBS, but dynamically continuous recrystallization is very helpful.