The preparation techniques of semi-solid hypereutectic Al-Si alloys have been discussed

including semi-solid stirring

spray forming and thixoforming

duplex casting

modification and isothermal holding process. The morphology of primary Si can be effectively improved and size of the Si particles is reduced through these techniques. An amount of a solid form during semi-solid processing. The solid fraction in the semi-solid slurry can be adjusted in semi-solid state. The hypereutectic Al-Si alloys with desired microstructure are well recognized.