对AZ31镁合金进行了不同轧角的冷轧及退火处理以细化其晶粒尺寸,然后在不同变形条件下对AZ31镁合金进行拉伸试验,研究了应变速率、变形温度、晶粒尺寸等因素对镁合金塑性的影响,并探讨了其超塑性的变形机理.结果表明:随着变形温度的升高,合金的流变应力单调递减,伸长率增大;在150~300 ℃,合金的变形激活能为90 kJ·mol-1,变形机制是晶界扩散控制的位错蠕变机制;在300~350 ℃,变形激活能为123 kJ·mol-1,变形机制是晶格扩散控制的晶界滑移;此合金的塑性成形条件适合工业生产.

AZ31 alloy was cold rolled under different rolling angles and subsequently annealed to refine the grain size.The effects of deformation conditions on the plasticity were investigated through tensile tests under different temperatures,strain rates and grain sizes.Meanwhile,superplastic deformation mechanism was investigated.The results show that the flow stresses were decreased and the elongations were increased with the temperature increase.In the temperature range of 150-300 ℃,the deformation activation energy was 90 kJ·mol-1,the deformation mechanism was dislocation creep controlled by grain boundary diffusion.In the temperature range of 300-350 ℃,the deformation activation energy was 123 kJ·mol-1,the deformation mechanism was grain boundary slip controlled by lattice diffusion.The plastic deformation conditions of the alloy were suitable for industrialized production.