Solidification and microstructure characterizations of eutectic aluminum‐silicon casting alloy with the addition of tin

Abstract

The effects of tin (Sn) addition on aluminum‐silicon and α‐aluminum phase solidification parameters as well as eutectic aluminum‐silicon casting alloy microstructure are systematically investigated. In this research, these characteristic parameters are examined by using computer‐aided cooling curve thermal analyses. The results of microstructure analyses and cooling curves show that tin alters silicon structure. By increasing the amount of tin up to 1 wt.%, α‐aluminum phase nucleation temperature, aluminum‐silicon phase growth temperature, and last phase solidus temperature increase. The mean area of silicon particles decreases when 0.1 wt.% tin is added but by its further increasing up to 1 wt.%, silicon particle mean area increases. It means that increase of tin content does not lead to silicon structure modification in this type of aluminum‐silicon alloy. Besides, by increasing the amount of tin, the reaction temperature of the last phase is increased by the formation of intermetallic compounds such as ternary compounds (Al−Si−Sn).