The semi-solid hypereutectic Al-20Si alloys have been prepared by electromagnetic stirring

modification and combination action

respectively.The effects of combination action of electromagnetic stirring and modification on growth and morphology of primary Si in hypereutectic Al-20Si alloy were observed.The results show that compared with that of by modification and electromagnetic stirring

the microstructure of primary Si in hypereutectic Al-20Si alloy prepared by combination means is finer and more roundness

decreased by 25.19 % in average grain size and increased by 8.40 % in average roundness

meanwhile

microstructure of eutectic Si can be spheroidized.The mechanism of combination refinement is revealed that applied rotating magnetic field after modification has promoted the diffusion of modifier to make the mutual destruct between more primary Si and eutectic Si structure

enhancing the effects of modification and electromagnetic stirring and refining microstructure.