Compound modification of hypereutectic Al-Si alloy was conducted by adding P+RE.The results indicate that P+RE compound modification has excellent effects on both primary Si and eutectic Si phases.Rosette primary Si size is greatly refined with the passivation of edges

and eutectic Si phase is converted from acicular structure into short-rod ones.The modification mechanism of P+RE on hypereutectic Al-Si alloy was described.