AZ41M镁合金热变形行为及本构方程

Hot deformation behavior and constitutive equation of AZ41M magnesium alloy

在变形温度300~450℃,应变速率0.005~1 s-1条件下,采用Gleeble-1500D热/力模拟试验机对AZ41M镁合金进行热压缩实验;结合微观组织,分析了变形温度、应变速率等对流变应力的影响;基于双曲正弦关系建立了流变应力本构方程,并对本构方程进行验证。结果表明,该镁合金为温度及应变速率敏感型材料,且其流变曲线具有明显的动态再结晶特征;压缩过程中AZ41M镁合金峰值应力随变形温度升高而减小,随应变速率升高而增大;实验条件下,由所建立的本构方程计算出的峰值应力与实验值基本吻合,绝对值最大平均相对误差仅为2.666%。

Hot compression tests of AZ41 M magnesium alloy were conducted on a Gleeble-1500 D thermo-mechanical simulator under the temperature range of 300-450 ℃ and strain rate range of 0. 005-1 s- 1. The effects of deformation temperature and strain rate on flow stress were analyzed and microstructure of the deformed alloy was examined. The constitutive equation was established by using hyperbolic sin function and the accuracy of the constitutive equation was also verified. The results show that AZ41 M magnesium alloy is sensitive to the changes of temperature and strain rate,and the flow stress curves of this alloy exhibit a typical flow behavior with dynamic recrystallization softening. The peak stress decreases with the increasing of deformation temperature and increases with the increasing of strain rate. The peak stress values calculated by the constitutive equation agree well with the experimental results under experimental conditions,the absolute value of the maximum average relative error is 2. 666%.