Abstract:The silicon modification was prepared by adding Te and Sb elements in the smelting process. The chemical composition of the material was determined by inductively coupled method, the mechanical properties, morphology and microstructural evolution of silicon under different T6 states were analyzed by DSC, OM, SEM, EDS, TEM and Universal testing machine. The results show that the number and density of Te, Sb and Si, Mg elements dissolve in the primary α-Al matrix and the endothermic peak among from 520℃ to 530℃ rises with the increase of the solid solution and aging temperature, together with an increased solution supersaturation of silicon in the quenching moment. Whereas, the quantity of Al4(Te,Sb) eutectic phase reduces continuously, the morphology of silicon particles change from pin-like, polygonal and long-rod to short-rod like, oval and spherical, the average size is merely 9 μm. The average tensile strength, yield strength, elongation, reduction of area and Vickers hardness after solidifing at 545℃ for 20h and aging at 170℃ for 10h with the polyethylene glycol quenching medium are 360MPa, 307MPa, 10.4%, 13.8% and 122, dimple morphology is the dominated fracture surface, accompanied by some intergranular fracture zone, and the average length of Mg2Si phase is about 224nm.