【摘要】 在温度为220³80℃和应变速率为0.001¹s^-1的条件下进行等温热压缩,研究铸态AZ91D镁合金的变形行为和动态再结晶行为。讨论变形温度和应变速率对动态再结晶行为的影响。结果表明,动态再结晶晶粒的形核和长大极易在高温和低应变速率的条件下发生。为预测动态再结晶的演变过程,在真实应力—应变曲线数据的基础上,提出AZ91D镁合金的动态再结晶动力学模型。该模型揭示动态再结晶的体积分数随着真实应变的增加而增加,其增长趋势呈典型的"S"曲线。通过对比发现由动力学模型所预测的结果和微观组织观测的数据具有很好的一致性,验证了所建立的AZ91D镁合金动态再结晶动力学模型的准确性。更多还原

【Abstract】 The flow behavior and dynamic recrystallization（DRX） behavior of an as-cast AZ91 D alloy were investigated systematically by applying the isothermal compression tests in temperature range of 220-380 ℃ and strain rate range of 0.001-1 s^-1.The effect of temperature and strain rate on the DRX behavior was discussed.The results indicate that the nucleation and growth of dynamic recrystallized grains easily occur at higher temperatures and lower strain rates.To evaluate the evolution of dynamic recrystallization,the DRX kinetics model was proposed based on the experimental data of true stress-true strain curves.It was revealed that the volume fraction of dynamic recrystallized grains increased with increasing strain in terms of S-curves.A good agreement between the proposed DRX kinetics model and microstructure observation results validates the accuracy of DRX kinetics model for AZ91 D alloy.更多还原