Abstract:Al-Si-Sc-Ce alloys with various Ce contents were prepared by molten salt electrolysis for studying their microstructure and mechanical properties. It is found that Ce refines the alloys with turning the primary α-Al from dendrite into round structure, and AlSi2Sc2 phase from long flake-like into network-like (their length from 1 000 μm down to 200-500 μm). The morphology of eutectic Si changes from plate-like into fiber-like, with drops in average area, roundness and average length of Si particles. A ternary CeAl2Si2 phase is also formed via eutectic reaction in the alloys. The microhardness of Al-7Si-0.79Sc-0.62Ce alloys is higher than that of Al-7Si-0.82Sc alloys, where the hardness values of the eutectic Si, Sc-containing and Ce-containing phases rise by 8.5%, 49.7% and 99.3 %, respectively. The mechanism for such improvement is related to Ce induced refinement.