Influence and mechanism of spreading and solidification behavior on cross section geometry of tin single tracks formed by liquid metal flow rapid cooling additive manufacturing

Tin single tracks were formed by a self-developed liquid metal flow rapid cooling additive manufacturing equipment with different superheats. The forming process was simulated by Flow 3D software. The influence and mechanism of the spreading and solidification behavior of molten tin after contacting with the substrate on the cross section geometry of tin single tracks were analyzed. The simulation results were also compared with the experimental results. The results demonstrate that when the superheats of molten tin are 50 degrees C, 100 degrees C and 150 degrees C, the spreading levels before solidification of molten tin are 76%, 80% and 82%, respectively, and the spreading behavior has an important influence on the cross section geometry of tin single tracks. When the superheat of molten tin increases from 50 degrees C to 150 degrees C, the cross section width of tin single tracks increases from 8.5mm to 10.9mm, and the solidification behavior has a certain influence on the cross section geometry of tin single tracks. The molten tin spreads rapidly to both sides after contacting with the substrate, and the spreading time is much shorter than the solidification time. The solidification behavior begins at the middle stage of the spreading behavior, and develops preferentially on both bottom sides of molten tin, which has a certain hindering effect on spreading behavior. The cross section geometry of tin single tracks and the influence of different superheats on cross section width and height of tin single tracks obtained by simulation are consistent with the experimental result, which verifies the reliability of the simulation.