Superplasticity of Spray Deposited 5083 Al-Mg Alloy

The superplasticity of spray deposited and thermomechanical processed 5083 Al-Mg alloy is investigated in this paper. The results show that spray deposited 5083 A1 exhibits an equiaxed grain morphology with an average size of 15μm and porosity in the range of 0.1 vol. % to 5 vol. %. Two distinct TMP procedures are employed to close porosity and refine grain size: extrusion plus rolling and direct rolling. The material processed using the former method exhibits a relatively high superplasticity with a maximum superplastic elongation of 465%, whereas that processed using the latter method exhibits a maximum superplastic elongation of 295%. Materials processed using extrusion plus rolling and direct rolling both exhibit similar stress-strain behavior and strain rate sensitivity factors. The strain rate factors are in the 0.3 to 0.5 range. The difference in their superplastic elongation is possibly the result of differences in grain size and available cavity nucleation sites provided by closed gas pores.