Effect of zirconium and magnesium additions on properties of Al–Li based alloy

The effect of additions of 0·08 and 0·14 wt-%Zr on the microstructure and mechanical properties of an Al–2·5Li–2Mg alloy has been studied. It has been found that the alloy having higher Zr content has a finer as cast microstructure as well as finer as extruded and solution treated microstructures with smaller subgrains. The alloy containing 0·14 wt-%Zr ages more rapidly and exhibits higher strength and fracture toughness, but a lower percentage elongation in the aged conditions. The effect of 2,3, and 4 wt-%Mg on the microstructure and properties of an Al–2·5Li–0·1Cu–0·14Zr alloy has also been studied. It has been found that the addition of Mg above 2 wt-% results in a deterioration in mechanical properties. The deterioration is attributed to the presence of Al2LiMg precipitates.MST/1861