Relation between surface tension and microstructural modification in Al–Si alloys

A relationship between the surface tension of Al–Si alloys and microstructural modifications has been proven by theoretical analysis and validated by microstuctural analysis. The surface tension is mainly controlled by the quantity of the modifier, and the modification time is less important. The modification temperature was found to have little effect on the microstructure of the alloys. A specific relation between the surface tension and the degree of modification has been established by experiments. When the surface tension is above 530 mN/m, partial modification occurs. When the surface tension is between 400 mN/m and 530 mN/m, moderate modification occurs. When the surface tension is below 400 mN/m, excellent modification occurs.