Effect of thermal processing on microstructure and mechanical properties of AZ80 magnesium alloy

The influences of deformation temperature and deformation degree on the mierostructure and mechanical properties of AZ80 magnesium alloy were investigated by the adoption of isothermal plain strain compression experiment. The results show that thermal compression processing can refine the grain size and the tensile strength of all the deformed AZ80 magnesium alloys is increased to the maximum of 320 MPa. With the increasing of deformation temperature, the tensile strength decreases; with the increasing of the deformation degree, the tensile strength increases significantly in the temperature range of 200-300 ℃ and becomes stable at temperature higher than 300 ℃. During the compression processing of AZ80 magnesium alloys, at lower temperature(<300 ℃), dynamic recrystallization is incomplete and a certain hardening effect is preserved, which makes great effect of deformation degree on the properties. At higher temperature (>300 ℃), dynamic reerystallization is complete and refined grainstrengthening is dominant, leading to little effect of deformation degree on mechanical properties.