Effect of calcium content on the microstructural evolution and mechanical properties of wrought Mg–3Al–1Zn alloy

The effect of Ca element on the hot workability and microstructure evolution of AZ31 magnesium alloy was investigated. Conventional AZ31, AZ31 + 0.7 wt.%Ca, and AZ31 + 2.0 wt.%Ca alloys were tested. Electron back scattered diffraction microscopy revealed that the alloys containing Ca exhibited much finer and more homogeneous microstructure than the conventional AZ31 alloy. Hot compression and tensile tests showed that the Ca element generally increased flow strength and decreased ductility at low temperature. High temperature elongation was considerably improved by the operation of the thermally activated process. TEM work suggested that the large volume fraction of fine (Mg, Al)2Ca particles played an important role in preventing significant grain growth of the AZ31 + 2.0Ca alloy.