Improvement in the strength and ductility of Al-Mg-Mn alloys with Zr and Sc additions by equal channel angular pressing

Abstract

AbstractThe effect of equal channel angular pressing (ECAP) on the structure and mechanical properties of Al-4 % Mg-1.5 % Mn-0.4 % Zr and Al-4 % Mg-1.5 % Mn-0.4 % Zr-0.4 % Sc (wt.%) alloys in the initial as-cast and heat treated states was studied. The ECAP processing was shown to lead to the formation of a predominantly submicrocrystalline structure with an average grain size of 850 nm for initial as cast state and 860 nm for initial heat treated state in the Al–Mg–Mn–Zr–Sc alloy and 1060 nm for initial as cast state and 1240 nm for initial heat treated state in the Al–Mg–Mn–Zr alloy. It is remarkable that both strength and ductility of the two alloys in the initial conditions were enhanced by ECAP. The highest strength was observed in the Al–Mg–Mn–Zr–Sc alloy (UTS = 425 MPa), in combination with elongation to failure of EL = 17 %. The characteristics of strength and ductility after ECAP for the Al–Mg–Mn–Zr alloy as well as for the Al–Mg–Mn–Zr–Sc alloy were similar whether the initial state was as-cast or as-heat treated.