Influence of equal-channel angular pressing on the superplastic properties of commercial aluminum alloys

Equal-channel angular (ECA) pressing was used to refine the microstructure in two commercial aluminum alloys, Al-2024 and the Supral-100 Al-2004 alloy. The ECA pressing was conducted at room temperature and at elevated temperatures for both alloys using several different processing routes. Tensile testing was carried out at elevated temperatures on both pressed and unpressed samples of each alloy in order to evaluate the effect of the pressing. This paper describes the influence of the ECA pressing on the subsequent mechanical properties of these two alloys. For both alloys, it is shown that the optimum superplastic conditions are influenced by the ECA pressing, and in practice there tends to be a decrease in the optimum temperature for superplasticity and a corresponding increase in the optimum strain rate. In addition, there was evidence for high strain rate superplasticity (HSR SP) in both alloys after the ECA pressing procedure.