Effect of minor Sc and Zr on the microstructure and mechanical properties of Al–Mg based alloys

A series of Al–Mg based alloy plates with thickness of 4 mm containing minor Sc and Zr were prepared. Tensile properties and microstructures of the alloys were studied. The results show that adding 0.2% Sc and 0.1% Zr to Al–5Mg alloy, the strength of the alloy increased by 150 MPa. Strengthening effect is the most outstanding among all minor alloying elements in aluminum alloys. Strength increment caused by adding minor Sc and Zr is attributed mainly to fine grain strengthening, precipitation strengthening of Al3(Sc, Zr) and substructure strengthening.