Mechanism of effect of stable cavitation on dendrite growth in ultrasonic field

Ultrasonic waves used in liquid alloys can produce refined grain structures, which mainly contributes to ultrasonic cavitation and acoustic streaming. According the bubble lifetime whether they are fragmented into “daughter” bubbles, be divided transient stable cavitation. Compared with cavitation, interaction between bubbles solidifying have been rarely investigated previously . In this work, effect of on dendritic growth succinonitrile (SCN)-8.3% (mole fraction) water organic transparent alloy is systematically by high-speed digital image technique numerical simulation. It found that when migration direction consistent growth, periodic high pressure generated oscillation process increases local undercooling, speeding up dendrites effectively. Meanwhile, concentrated stress inside induced linearly break fragments. Specifically, if there exist suspended around liquid-solid interface, periodically alternating flow field shear force their surrounding phase produced. As a result, nearby fragments will attracted those then transformed spherical grains.