Structure and mechanical properties of two Mg–Al–Ca alloys consolidated from atomised powder

Two Mg–Al–Ca alloys (A = Mg–9Al–5Ca; B = Mg–19Al–10Ca, wt-%) have been argon atomised, canned, and then consolidated by extrusion at 280 to 290°C. Alloy B exhibited a compressive fracture strength as high as 720 MPa after 1 h at 300°C while alloy A showed an ultimate tensile strength of 565 MPa and a tensile proof strength of 496 MPa as extruded. The corresponding ultimate strength to density ratios of 400 and 310 MPa m³ Mg^-1 of these and other ultrahigh strength rapidly solidified powder metallurgy (RSPM) magnesium alloys exceed or are comparable with the highest available values for ultra high strength RSPM aluminium alloys such as RSPM Al–15Ni–3Mm–5Zr (where Mm is misch metal) and RSPM Al–9·5Zn–3Mg–1·5Cu–4Mn–0·5Zr.