Determination of the Cavitation Range of Power Ultrasound in an Aluminum Alloy Melt

摘要

Power ultrasound has been widely used for improving the performance of aluminum alloy. However, it is difficult to observe the effect of ultrasonic directly on an aluminum melt at high temperatures. Therefore, an indirect method has been used to detect the cavitation range of ultrasonic waves in an aluminum melt. A titanium plate was inserted into the molten aluminum subjected to ultrasonic treatment for 20 hours. Then, the change in the surface morphology of the titanium plate was investigated. It was concluded that the ultrasonic cavitation range was approximately 82 mm in diameter. After the ultrasonic treatment of the melt, it was cooled in the resistance furnace. Subsequently, a microstructure analysis was conducted by cutting one half from the center of the aluminum ingot. An ellipse region of homogeneous macrostructure was obtained with the major axis of approximately 106 mm and the minor axis of approximately 86 mm. A 10 by 10 by 15 mm (length by width by height) block was then removed from the designated position of the half-section of the aluminum ingot and employed for the microstructure analysis. The analysis showed that the grain refinement effect at the center was better than at the edge, and the refinement in the vertical direction attenuated faster than in the horizontal direction.