Investigation on the spreading and solidification of supercooled gallium droplets during impact

Abstract The spreading and solidification of supercooled gallium droplets during impact affects the application of gallium-based liquid metals during 3D printing and spray coating. In this study, the impact process of supercooled gallium droplets was observed, and the influence of the dimensionless parameters, substrate materials, and substrate temperatures on the spreading and solidification of supercooled gallium droplets was analyzed. It was observed that the supercooled gallium droplets retracted slightly during the impact process and were likely to undergo solidification due to impact. The maximum spreading factor of the supercooled gallium droplet during impact was proportional to We1/2 (square root of the Weber number). The substrate material and substrate temperature less affected the maximum spreading factor, whereas they have a significant effect in determining whether the droplets solidify. The guidelines controlling the maximum spreading factor and the solidification of supercooled gallium droplets have been outlined in this study.