On the influences of Li on the microstructure and properties of hypoeutectic Al-7Si alloy

In this study, hypoeutectic Al-7Si alloys without and with Li additions were prepared by melt casting technique using a water-cooled copper mold. The influences of Li with varying content on the microstructure and properties of the hypoeutectic Al-7Si alloys were investigated. Various techniques including metallography and scanning electron microscopy (SEM) with energy dispersion spectrum (EDS) were used to characterize the microstructural evolution and phase assemblages. Vickers hardness and tensile tests were performed to investigate the mechanical properties of the alloys with varying Li additions. Fractured surfaces were observed to determine the predominant fracture modes in the samples without and with Li additions. Lastly, the mechanism responsible for the influences of Li on the microstructure and mechanical behavior of the hypoeutectic Al-7Si alloy were discussed and proposed.