THE EFFECT OF COOLING RATE AND CERIUM MELT TREATMENT ON THERMAL ANALYSIS PARAMETERS AND MICROSTRUCTURE OF HYPOEUTECTIC Al-Si ALLOY

摘要

In the present investigation, pure cerium ingots were added to Al-8% Si alloy melt to study its effect on the microstructure and cooling curve parameters. The melt treated alloy was solidified against sand base, stainless steel, brass, and copper chills to study the effect of chilling. Ce treated alloys solidified against sand base resulted in refinement of the eutectic silicon along with the formation of Al-Si-Ce ternary intermetallic compound. Addition of Ce to alloys solidified against chills resulted in the complete modification of eutectic silicon. Thermal analysis results revealed that the nucleation temperatures of eutectic silicon decreased on addition of cerium to the chilled alloys due to the synergistic effect of chilling and cerium addition. The degree of modification achieved was higher due to the decrease in the formation of Ce intermetallics at higher cooling rates.