Mechanical properties and microstructure of Al–Mg–Mn–Zr alloy processed by equal channel angular pressing at elevated temperature

An Al–Mg–Mn alloy containing Zr, and a standard 5083Al alloy were fabricated. The as-cast alloys were homogenized, hot extruded and hot ECAP (equal channel angular pressing). After hot extrusion, the ultimate strength of the Al–Mg–Mn–Zr alloy was 30.0 MPa higher than that of 5083Al, but the elongation was 10.1% lower. This was because the Al3Zr dispersoids in the Al–Mg–Mn–Zr alloy enhanced the strength and inhibited the recovery process during the hot extrusion, but simultaneously decreased the ductility. After hot ECAP, the strength of the Al–Mg–Mn–Zr alloy was still 32.6 MPa higher than that of 5083Al but without significant loss of the elongation. This implied that the fine-grained, high-angle boundaries microstructure produced by hot ECAP can effectively enhance the strength with little compromise of the ductility of the Zr-modified alloy.