Effects of the melt thermal treatment with composition compensation on morphology of primary Si in hypereutectic Al-20Si alloy were investigated. The results show that the technology can refine grain size of primary Si to approximately 36 μm within 100 min

exhibiting an obvious modification effect on the primary Si and a long duration time. So the melt thermal treatment with composition compensation is a simply and practical technology for modifying the primary Si in the Al-20Si alloy without modifier addition.