Forming limit diagram (FLD) is the most intuitive method to evaluate and analyze the forming performance of sheet metal, which is widely used in production. To examine the formability of AZ31 magnesium alloy and 7050 aluminum alloy, the simplified bulging models based on the Nakazima experiment are established by ABAQUS finite element (FE) software, and the maximum punch force criterion is adopted as the instability criterion. The forming limit diagrams of 7050 high-strength aluminum alloy at room temperature and AZ31 magnesium alloy at warm working conditions are obtained by extracting the in-plane strain of the adjacent element of the maximum strain element at the moment of instability. Compared with experimental observation shows that the Nakazima virtual model established in this paper can accurately predict FLD. In addition, the influences of lubrication conditions and virtual punching speeds on the bulging process of AZ31 and AA7050 sheet metals are also investigated. The results show that the better the lubrication environment, or the lower the punching speed, the better the formability of the sheet, and reducing the punching speed has a more significant improvement effect on the formability of AZ31 sheets.

成形极限图（FLD）是评估和分析钣金成形性能的最直观的方法，已广泛应用于生产中。为了检验AZ31镁合金和7050铝合金的可成形性，使用ABAQUS有限元（FE）软件建立了基于Nakazima实验的简化凸出模型，并采用最大冲力准则作为不稳定性准则。通过提取不稳定性瞬间最大应变元素的相邻元素的面内应变，可获得7050室温高强度铝合金和AZ31镁合金在热加工条件下的成形极限图。与实验观察结果比较表明，本文建立的中岛虚拟模型可以准确预测FLD。此外，还研究了润滑条件和虚拟冲压速度对AZ31和AA7050钣金膨胀过程的影响。结果表明，润滑环境越好，冲孔速度越低，板材的成形性越好，降低冲孔速度对AZ31板材的成形性有更显着的改善作用。