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

Abstract

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