Coupling acoustic cavitation and solidification in the modeling of light alloy melt ultrasonic treatment

The space industry requires strong lightweight alloys to decrease launching costs and to increase the reliability of components. One promising technique is the application of ultrasound to a solidifying melt, which has been demonstrated to enhance the thermo-physical qualities of the treated sample through grain refinement. The underlying mechanism is through acoustic cavitation; however, it is not well understood how cavitating bubbles disrupt the microstructure. Further understanding of the fundamentals of ultrasonic melt processing is required to optimize treatment parameters, thus enabling the efficient production of lighter, stronger alloys at an industrial scale. To achieve this goal and investigate the effect of cavitating bubbles on the solidification front, we present a high-order micro-scale acoustic cavitation model. This model is applied to the interaction between cavitating bubbles and a needle dendrite of succinonitrile 1 wt. % camphor organic transparent alloy for which high-speed digital imaging is available in the literature.