Research Progress on Silicon Phase Refinement in Hypereutectic Al-Si Alloys

Hypereutectic Al-Si alloys have attracted attention due to their good wear resistance, but coarse primary silicon and needle-like eutectic silicon in the microstructure limits their further widespread use. Some current methods of silicon phase refinement in hypereutectic Al-Si alloys, such as alloying, modification treatment, and improvement of preparation process, were reviewed.The effect of alloying on the microstructure of hypereutectic Al-Si alloys was mainly introduced; then the refining effects of various modifiers were compared and analyzed; the effect of improving the preparation process on the size and morphology of the silicon phase was discussed. Finally, the future research direction was pointed out: the development of new composite modifier suitable for wide use should be concentrated and combining modification and improvement of the preparation process should be used to obtain hypereutectic Al-Si alloy with more excellent properties.