以材料的临界损伤阀值为评判依据,采用数值仿真技术进行AZ80镁合金盖形件成形工艺优化。结果表明:采用坯料一道次挤压成形时,在反挤压成形盖形件外端直臂部位的损伤值超过材料的的塑性变形临界损伤阈值,产生塑性变形缺陷;采用两道次挤压成形时,盖形件挤压成形的最大损伤阈值降低到20,远低于材料塑性变形的临界损伤阈值,保证了盖形件的无缺陷成形。在此基础上,确定了该盖形件的优化成形工艺。 Based on the critical damage threshold of materials, numerical simulation was used to optimize the forming process of AZ80 magnesium alloy cap. The results show that the damage value of the straight arm at the outer end of the reverse extrusion profile exceeds the critical threshold of plastic deformation of the material when the blank is extruded by one pass. The plastic deformation defects are produced by two-pass extrusion , The maximum damage threshold of extrusion is reduced to 20, much lower than the critical damage threshold of material plastic deformation, which ensures the defect-free forming of the cap. On this basis, the optimal forming process of the cap is confirmed.