Abstract:The hot working behaviors of Mg-9Y-1MM-0.6Zr (WE91) magnesium alloy were researched in a temperature range of 653−773 K and strain rate range of 0.001−1 s⁻¹ on Gleeble−1500D hot simulator under the maximum deformation degree of 60%. A mathematical model was established to predict the stress—strain curves of this alloy during deformation. The experimental results show that the relationship between stress and strain is obviously affected by the strain rates and deformation temperatures. The flow stress of WE91 magnesium alloy during high temperature deformation can be represented by Zener-Hollomon parameter in the hyperbolic Arrhenius-type equation, and the stress—strain curves obtained by the established model are in good agreement with the experimental results，which prove that the model reflects the real deformation characteristics of the WE91 alloy. The average deformation activation energy is 220 kJ/mol at strain of 0.1. The microstructures of WE91 during deformation processing are influenced by temperature and strain rates.

Key words: rare-earth magnesium alloy; Zener-Hollomon parameter; flow stress model; microstructure