Isothermal hot compression experiments were conducted on homogenized Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr alloy to investigate hot deformation behavior at the temperature range of 673–773 K and the strain rate range of 0.001–1 s⁻¹ by using a Gleeble-1500D thermo mechanical simulator. Metallographic characterization on samples deformed to true strain of 0.70 illustrates the occurrence of flow localization and/or microcrack at deformation conditions of 673 K/0.01 s⁻¹, 673 K/1 s⁻¹ and 698 K/1 s⁻¹, indicating that these three deformation conditions should be excluded during hot working of homogenized Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr alloy. Based on the measured true stress-strain data, the strain-compensated Arrhenius constitutive model was constructed and then incorporated into UHARD subroutine of ABAQUS software to study hot deformation process of homogenized Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr alloy. By comparison with measured force-displacement curves, the predicted results can describe well the rheological behavior of homogenized Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr alloy, verifying the validity of finite element simulation of hot compression process with this complicated constitutive model. Numerical results demonstrate that the distribution of values of material parameters (α, n, Q and ln A) within deformed sample is inhomogeneous. This issue is directly correlated to the uneven distribution of equivalent plastic strain due to the friction effect. Moreover, at a given temperature the increase of strain rate would result in the decrease of equivalent plastic strain within the central region of deformed sample, which hinders the occurrence of dynamic recrystallization (DRX).

^{对均匀化的 Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr 合金进行等温热压缩实验，以研究在 673–773 K 温度范围和 0.001–1 s − 1}应变速率范围内的热变形行为，通过使用Gleeble-1500D 热机械模拟器。^{变形至 0.70 真实应变的样品的金相表征表明在 673 K/0.01 s - 1、673} K/1 s ^{- 1}和 698 K/1 s ^{- 1}的变形条件下会发生流动局部化和/或微裂纹, 表明均质化 Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr 合金在热加工过程中应排除这三种变形条件。基于实测的真实应力应变数据，构建应变补偿Arrhenius本构模型，并将其纳入ABAQUS软件的UHARD子程序，研究均质化Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr合金的热变形过程。通过与实测力-位移曲线对比，预测结果能够很好地描述均质化Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr合金的流变行为，验证了该复杂本构热压缩过程有限元模拟的有效性模型。数值结果表明，材料参数值的分布（α、n、Q和 ln  A) 变形样本内是不均匀的。由于摩擦效应，这个问题与等效塑性应变的不均匀分布直接相关。此外，在给定温度下，应变速率的增加会导致变形样品中心区域的等效塑性应变降低，从而阻碍动态再结晶（DRX）的发生。