Effect of Sb and Al-3P Complex Modification on Solidified Microstructure and Mechanical Property of Hypereutectic Al-18Si Alloys

The present investigation involved the modified of Al-18Si alloys with the Sb and Al-3P at a temperature of 850 degrees C. The findings indicated that the Sb can inhibit the formation of initial Si crystals in Al-18Si alloys, while simultaneously promoting the process of their growth. With a concentration of 0.3 wt %, the presence of Sb exhibited the most potent inhibitory impact on the precipitated phase of primary Si, resulting in the smallest average size and area percentage for it in Al-18Si alloys. Furthermore, there was an 11.4% enhancement in the tensile strength and a significant 190% increase in the elongation. The Al-3P and 0.3 wt % Sb complex modification can enhance the formation of primary Si crystals in Al-18Si alloys while preventing their growth. The 0.4 wt % Al-3P modified Al-18Si-0.3Sb alloys results in the smallest size of primary Si in the solidified microstructure of the alloys. The complex modification of Al-18Si alloys enhances their tensile strength by 13.8% when compared to Al-18Si-0.3Sb alloys.