The Effects of Li on the Tensile Properties of 380 Aluminum Alloys

The effects of Li on the microstructure and mechanical properties of Type A380 aluminum casting alloys have been examined. It is shown that, as the Licontent is increased up to 0.1 wt.pct in the base alloy (Al–8.5 wt.%Si–3.5 wt.%Cu–1 wt.%Fe), Li successfully modifies the morphology of the β-Al5FeSi and eutectic Si phases from coarse intersected and branched platelets into finer and fibrous ones. The 0.06%wt Li-containing alloy exhibits higher strength and elongation, presumably due to both finer β-Al5FeSi and eutectic Si phases. In amounts greater than 0.06%wt lithium, Reduction of the strength and elongation can be due to increasing porosity and creation of other undesirable phases