Effect of hot-deformation on microstructure and mechanical properties of AZ80 magnesium alloy

In this study, the microstructure evolution of AZ80 magnesium alloy, in particular the precipitation mechanism of beta Mg17Al12 phase, during hot deformation at different temperatures was characterized by SEM and the effect of the morphology of the beta p phase on tensile properties at room temperature was investigated. It was revealed that AZ80 cast ingot exhibited a net-work microstructure with the Mg17Al12 particles precipitating mainly in the vicinity of the grain boundaries. The net-work largely remained after the homogenization treatment. Hot-compression tests were carried out under a constant compressing speed of 8 mm/s in the temperature range 200-400 degrees C and an equivalent strain range 0.80-2.65. It was found that the net-work was destroyed during hot-compression and the following Mg17Al12 morphologies were observed depending on the hot-compression temperature and strain: strip, fine granular and lamellar. Hot-deformation has significantly improved the mechanical properties of the alloy due to refinement of grain size and change of Mg17Al12 morphology from net-work to favorable fine granular shape. (C) 2013 Published by Elsevier B.V.