Mechanism of AC arc-ultrasonic on joint of SiC_p/6061Al MMCs

To improve the welding performance of SiCp/6061Al, arc-ultrasonic technology was applied in welding process, and the filling material was Al-15Ti-3Si. The mechanism of arc-ultrasonic on microstructures of joint of SiCp/6061Al MMCs in plasma arc "In-situ" welding with different arc-ultrasonic frequency was investigated. The result shows that the Al₃Ti phase is obviously refined by ultrasound. With the frequency 30, 50 and 60 kHz, the Al₃Ti is crushed to granular or block, and uniformly distributed in the weld. With the frequency 20, 40, 70 kHz, the Al₃Ti is partially crushed, and distributed at the original location along the vertical in the weld. Analysis shows that the arc-ultrasonic impacts the morphology and distribution of Al₃Ti mainly by cavitation and acoustic streaming.