Hot deformation behavior of as-extruded AZ81 magnesium alloy was investigated by compressive testing with the Gleeble-1500D thermal simulator at 320～440 ℃ and strain rate of 0.001～1s-1 with 60% deformation degree. The flow behavior can be described by the hyperbolic sine constitutive equation

and average activation energy reaches 182.17kJ/mol

higher than the activation energy for self-diffusion. The processing maps were calculated and analyzed according to the dynamic materials model. Combined with microstructure observation

process of hot deformation of as-extruded AZ81 magnesium alloy was analyzed. In conditions of 320～440℃ and strain rate of 0.001～1s-1 with 60% deformation degree

when instability criterion is more than zero

AZ81 magnesium alloy exhibits desirable hot deformation performance. Based on the processing maps

the optimized processing parameters range during hot deformation process were presented in the experimental parameters range

where hot deformation temperature was 380～400℃ and strain rate was 0.01～0.1s-1.