Effect of ultrasonic field on the microstructure and mechanical properties of sand-casting AlSi7Mg0.3 alloy

The injection of ultrasonic wave into a melt during casting can refine grain size, improve grain distribution, and thereby enhance casting performance. The available studies on ultrasonic-assisted casting are mostly about inserting a transducer directly into the melt. Such a method is not suitable for sand casting. Therefore, the study of ultrasonic sand casting by indirectly injecting ultrasonic waves into an aluminum alloy melt through a sand mold was proposed and carried out in this study. The effects of ultrasonic waves of different powers at different solidification stages on the microstructure and mechanical properties of the melt were studied. Compared to conventional sand casting, the samples prepared by ultrasonic sand casting have finer grains and better grain distribution, as well as higher mechanical properties. Moreover, the sample's performance improves to different levels when the same ultrasonic wave is injected at different periods, when compared to the injection of ultrasonic waves with different powers in the same period.