The deactivation mechanism of Sr is not clearly established forBi addition. It was found that the interaction is not dependent onthe sequence of addition, whether Bi is added first or after Sr to themolten metal. In addition, the melt was stirred before thermal anal-ysis sampling. So, it is believed that other mechanisms in addition tothe settlement, surface oxidation and vaporization [4] are respon-sible for the negative interaction between Sr and Bi. According tothe phase diagram, it can be suggested that formation of binary orternary compounds between Bi and Sr along with other availableelements like Al, Si and Mg before Al–Si eutectic transformation isone option to reduce the free Sr available in order to modify theSi. It seems that two solutions could be considered to mitigate themutual interaction of Bi with Sr modification of Al–Si casting alloys:(1) use of the established map to achieve modification by addingSr at Sr/Bi ratio, which is sufficient to compensate for the amounttied up stoichiometrically with the Bi, and (2) development of tech-niques such as adding elements as scavengers to remove Bi presentin the melt.