The Influence of Ultrasonic Cavitation on the Formation of Fe-Rich Intermetallics in A383 Alloy

The effect of ultrasonic treatment (UST) on the formation of Fe-rich intermetallics (including sludge) in the A383 alloy is investigated for different processing temperatures in the present study. Differential scanning calorimetry is used to analyze the precipitation temperature of the sludge phase. The results revealed that the sludge will precipitate at a temperature above that of the Al matrix and the precipitation temperature decreases with an increasing cooling rate. UST cavitation applied at different temperatures (600 A degrees C to 750 A degrees C) during the solidification process breaks the sludge into small island-like pieces. However, the aggregation trend of the sludge is not changed. Sludge with small size and uniform distribution is obtained when UST is applied at 600 A degrees C, which is lower than the precipitation temperature of the sludge. At the highest temperature (850 A degrees C), the application of UST has no effect on the formation of either sludge or alpha-Fe intermetallics. At 750 A degrees C, UST promotes the formation of the sludge when applied at 750 degrees C.