Modification of the Si Eutectic Phase in A319 Alloy With Lithium Additions

Lightweight aluminum alloys play a significant role in improving the range and effectiveness of electric vehicles in the automotive industry. Lithium (Li) as an additive element in small quantities has the ability to reduce the weight and improve the mechanical properties of aluminum alloys. In this research, an addition of 0.2 wt.% Li reduced the Si eutectic reaction temperature significantly (‚âà15 °C). Further additions did not provide a significant improvement in this reaction temperature. At this Li concentration (0.2 wt.% Li), the Si eutectic phase was modified to fine grains of spherical morphology. Further additions did not change the morphology of the eutectic phase. XRD analysis determined that the observed blocky phase in the microstructure was AlLiSi, and the size of the particles increased with the Li additions. The porosity in the samples of Li containing alloys was non-uniform and this prevented the development of trends in the density and micro-hardness.