High-speed visualization measurement for breakup process of liquid metal with solidification

Abstract

In recent years, Additive Manufacturing (AM) technology such as 3D printing has attracted much attention. In order to produce high-quality metal powders as printing materials, it is necessary to elucidate the phenomena of liquid metal splitting accompanied by solidification, which is manifested in the powder manufacturing process. So far, various experiments have been conducted on the atomization method, but the mechanism for determining powder properties has not been clarified. In particular, there is insufficient knowledge about the phenomenon of molten metal splitting along with solidification. Therefore, in this study, we investigate the breakup process of a single ligament of 42Sn-58Bi, which is a kind of fusible alloy with a melting point of 139 ℃. A high-speed camera is used to visualize the pinch-off process of the ligament. The variation of the neck diameter of the ligament is traced during the fragmentation process. When the initial temperature is high, we found that the neck diameter thins down following a power law of 2/3, corresponding to the trend derived from capillary time scale. On the other hand, as the initial temperature gets lower, the neck diameter becomes thinner than that predicted by the capillary time scale just before breaking up, which is attributed to the influence of solidification.