Effect of strain, strain rate and temperature on workability of AZ80 wrought magnesium alloy

The hot deformation behavior of AZ80 wrought magnesium alloy was studied in the temperature range of 523-673 K and the strain rate range of 0.01-10 s−1 using hot compression tests. Through the flow stresses behavior, the processing maps were calculated and analyzed according to the dynamic materials model. The stable, metastable and unstable regimes were clarified. The optimum processing conditions were suggested as following: the DRX regions in Domain #1-0.25, Domain #2-0.25, Domain #1-0.45, Domain #2-0.45, Domain #3-0.45, Domain #1-0.65 and Domain #1-0.85, and the DRV regions in Domain #3-0.25 and Domain #4-0.45. In each “safe” DRX domain, it is preferable to conduct hot working in the small region around efficiency peak point. The strain has a great influence on the processing maps. The whole area of the “safe” domains increases with the increase of true strain from 0.25 to 0.65, while it decreases with the increase of true strain from 0.65 to 0.85. The results of kinetic analysis reveal that the values of apparent activation energy in all the domains are higher than that for self-diffusion in pure magnesium (135 kJ/mol), and the deformation mechanism in all the domains is likely to be cross-slip.