Research Summary Aluminum: Cast Shop and AlloysBoth the theoretical analysis and experiments on Al-Si alloys have shown that a relationship between the surface tension and the modifi cation of Al-Si alloys exists. A new method for the rapid prediction of the the modifi cation level of Al-Si alloys by surface tension has been introduced. The quantity of the modifi er is found to have the greatest effect, followed by the time of the modifi cation and then the temperature. In Al-Si alloys, when the surface tension is above 530 mN/m, the modifi cation level is partial. When the surface tension is between 400 mN/m and 530 mN/m, the modifi cation level is moderate. When the surface tension is below 400 mN/m, the modifi cation level is perfect.