Effect of ultrasonic treatment on microstructures of hypereutectic Al-Si alloy

摘要

The hypereutectic Al-23%Si alloy was treated with ultrasonic wave. A novel horn crucible was designed specially for this experiment. The horn crucible was a part of ultrasonic horn, and the molten alloy was treated direct in this crucible. The morphology, size, and distribution of the microstructures of the Al-Si alloy were observed by means of an optical microscope. The results show that after the hypereutectic Al-23%Si alloy was treated by ultrasonic wave, the hydrogen bubbles in the alloy melt were removed, the primary Si phase was refined, the morphology of the primary α-Al dendritic crystal was changed to equiaxial crystal, and the eutectic lamellar spacing increased. The mechanisms of ultrasonic treatment improving the microstructures of the hypereutectic Al-Si alloy were discussed.