中文摘要：

采用Gleeble-1500热模拟试验机研究了铸态AZ91镁合金在变形温度为473～673K，应变速率为0．005～5s^-1条件下的压缩变形行为。结果表明，实验舍金的流变应力随变形温度的升高而降低，随应变速率的增大而增大，并且符合Zener-Hollomon参数的幂指数关系。通过对实验数据进行多元回归分析，所得流变应力方程中的参数口、A和变形激活能Q分别为0．1015，2．3863×10^9和175．667kJ／mol。合金在不同温度阶段呈现不同的组织特征，当变形温度为473K时，合金显微组织以孪晶、滑移带为主；当变形温度为573～673K时，则以动态再结晶晶粒为主。为进一步系统研究该合金的塑性加工提供一定的实验依据。

英文摘要：

Compression tests of as-cast AZ91 magnesium alloy were performed on Gleeble- 1500 at deformation temperature ranging from 473 to 673K and strain rate from 0. 005 to 5 s^-1. The results show that the flow stress of the tested alloy decreases with the increase of deformation temperature and increases with the increase of strain rate, which can be represented by a Zener-Hollomon parameter in the power-type equation. Parameters β, A and the deformation activation energy Q in the flow stress equation are 0. 1015, 2. 386 3 × 10^9 and 175. 667 kJ/mol respectively, derived from experiment data through multiple regression analysis. AZ91 magnesium alloy shows different characteristics of the microstructure at different deformation temperature. The microstructure of AZ91 magnesium alloy mainly consists of twinning and slip band at 473K and dynamic recrystallization grain between 573 and 673 K, respectively. Research results may lay the foundation for systematic study on plastic processing of AZ91 magnesium alloy.