State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, PR China.
State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, PR China.
Ultrason Sonochem. 2018 Dec;49:249-259. doi: 10.1016/j.ultsonch.2018.08.009. Epub 2018 Aug 11.
The cavitation characteristics at filler metal/substrate interface during ultrasonic-assisted soldering were first recorded by high-speed photography in this work. Two kinds of bubbles, steady cavitation bubbles and transient cavitation bubbles were observed. Steady cavitation bubbles did not collapse within one acoustic period and could last longer than 50 acoustic periods. Transient cavitation bubbles formed and collapsed within one acoustic period. The cavitation process was divided into two stages based on the cavitation characteristics. The first violent cavitation stage was in fact the degassing process, which lasted approximately 2700 acoustic periods and was affected by the gas content trapped inside the filler metal and the stronger vibration at the initiation stage of ultrasonic-assisted soldering. The second steady cavitation stage had obvious low bubble density and accounted for the most of the soldering process. Higher cavitation densities were observed when small channel width and large ultrasonic power were used because of larger sound pressures inside the filler metal.
在这项工作中，首次通过高速摄影记录了超声辅助钎焊过程中填充金属/基板界面处的空化特性。观察到了两种气泡，即稳定空化气泡和瞬态空化气泡。稳定空化气泡在一个声波周期内不破裂，并且可以持续超过 50 个声波周期。瞬态空化气泡在一个声波周期内形成和破裂。根据空化特性，将空化过程分为两个阶段。第一个剧烈空化阶段实际上是脱气过程，持续了大约 2700 个声波周期，并且受到填充金属内部被困气体含量和超声辅助钎焊起始阶段更强振动的影响。第二个稳定空化阶段具有明显的低气泡密度，并且占钎焊过程的大部分。当使用小通道宽度和大超声功率时，观察到更高的空化密度，因为填充金属内部的声压更大。
