Structure and properties of an ultra-high strength 7xxx aluminum alloy contained Sc and Zr

An ultra-high strength aluminum alloy was produced by casting and then extruded to rods. The effect of heat treatment on the microstructure and mechanical properties of the alloy was investigated. After single ageing (120℃, 24 h), the tensile strength was 812.4 MPa and the elongation was 6.2%. After retrogression reaging (RRA), the tensile strength was 751.2 MPa and the elongation was 6.4%. The strengthening mechanism is considered as fine grain strengthening, substructure strengthening and dispersion strengthening by Al₃(Sc, Zr).