(1. 哈尔滨工业大学 材料科学与工程学院，
哈尔滨 150001;
2. 哈尔滨理工大学 机械动力工程学院，
哈尔滨 150008)
摘 要: 对轧制态MB15镁合金进行了超塑性拉伸实验， 结果表明：晶粒尺寸为5.9μm的MB15镁合金板材, 在温度为573K、 初始应变速率为5.56×10-4s-1的变形条件下，获得的最大延伸率为309%， 应变速率敏感指数为0.34； 当真应变为0.3时， 试样的晶粒尺寸为4.5μm，说明在拉伸初始阶段轧制镁合金可以获得细晶组织， 同时发生了部分动态再结晶。 利用扫描电镜观察断口发现典型的超塑性空洞形貌特征。 通过胀形实验可以看出，该镁合金板材的超塑成形性能好，具有良好的超塑性成形应用潜力。
关键字: 超塑性； 动态再结晶； 气胀成形； 镁合金
（1.School of Materials Science and Engineering, Harbin Institute of Technology,
Harbin 150001, China;
2.School of Mechanical and Power Engineering, Harbin Science and Technology University, Harbin 150008, China）
Abstract:Superplasticity of a rolled magnesium alloy Mg-Zn-Zr was investigated at 573K and a strain rate of 5.56×10-4s-1. The maximum elongation is 309% and the strain rate sensitivity exponent m is 0.34. The grain size of the rolled magnesium alloy is 5.9μm. However, the grain size of the specimen deformed to a true strain of 0.3 is 4.5μm. The grain refinement is attributed to dynamically continuous recrystallization during the initial stage of tensile test. SEM observation shows that the typical cavities are obvious in fracture surfaces of tensile samples after superplastic deformation. Finally, the successful superplastic gas pressure bulging forming experiment proves the satisfying superplastic forming capability of the alloy.
Key words: superplasticity; dynamic recrystallization; gas pressure bulging; magnesium alloy
