Optimizing the Melt Treatment of Piston Alloys Using Thermal Analysis Technique

The effects of Cu-P and Al-Sr master alloys as strong modifiers have been investigated on the microstructure of commercial Al-Si (12-13%Si) alloys. Thermal analysis has been employed to examine the morphological changes of Si particles and identify the optimum concentration of P and Sr to achieve fine and well-distributed eutectic and primary silicon structures.

Additions of 0.05% to 0.075% P or Sr have been found to yield the most optimum modification and refining of the structure. The results show that the variation in nucleation temperature of primary phase and the eutectic temperature are the most important parameters.