Abstract: Gleeble-3500 thermal simulation testing machine was used to conduct hot compression experiments on the annealed Mg-8.3Gd-4.4Y-1.5Zn-0.8Mn alloy. The hot deformation behavior of the alloy was investigated at temperatures of 380-500 ℃, true strain rates of 0.001-1 s^-1, and a deformation degree of 60%. The constitutive relationship of the alloy was calculated. The hot processing map was established according to the dynamic material model. The machinable and rheological instability regions during the hot deformation process were determined. The evolution of the microstructure under different deformation conditions was analyzed. The results show that the flow stress of the alloy increases with the increase of the strain rate, and decreases with the increase of deformation temperature, the deformation activation energy, Q=252 517 J/mol, the stress index, n=4.45; Reducing the deformation rate and increasing the deformation temperature both contribute to the occurrence of dynamic recrystallization. Long period stacking ordered phase affects alloy recrystallization process according to morphology. It is inferred from the hot processing map that the possibility of instability of this material increases with the increase of the degree of deformation. Combining the microstructure in the peak area to judge the appropriate processing conditions are around the deformation temperature of 460 ℃ and the strain rate of 0.01 s^-1.

Key words: Mg-Gd-Y-Zn-Mn alloy, hot deformation, constitutive relationship, hot processing map, microstructure