Effect of scandium on superplasticity of Al-Mg alloys

The superplastic behavior of adding 0.22% Sc into the Al-6Mg alloy was studied by simple superplastic pretreatment process-warm rolling and cold rolling. The optimum superplastic temperature and strain rate of the alloys were defined and satisfactory results were obtained during the superplastic deformation at 811 K and initial strain rate Ε0=1.67×10-3 s-1. The average elongation of Al-6Mg-0.22Sc alloys reaches to 1125%, and the maximum elongation is 1200%, maximum m value (strain rate sensitive index) is 0.879. But under the same condition the elongation and maximum m value for Al-6 Mg alloy were only 377% and 0.595, respectively. The superplastic deforming mechanism for Al-6Mg -0.22Sc alloys was also discussed.