Effect of Al and Mn additions on rolling and deformation behavior of AZ series magnesium alloys

Hot rolling and tensile deformation characteristics of six AZ series magnesium alloys containing 3, 4, and 6 wt% aluminum were studied at two different levels of manganese. It was found that increasing the Al content to 6 wt% resulted in edge cracking during hot rolling. On the other hand, addition of Mn to some extent compensated for the detrimental effect of Al. Tensile deformation at various strain rates and temperatures revealed that the AZ series alloys undergo different combinations of deformation mechanisms, from dislocation creep dominating at high strain rates to grain boundary sliding dominating at low strain rates. The Al content of the alloy did not appear to affect these mechanisms significantly, but Mn showed a noticeable effect. The effect of Al content on flow stress was evident at high strain rates, but was not at low strain rates. Analysis of elongation to fracture at two levels of Mn revealed that Mn improves ductility by increasing the extent of uniform elongation.