Application of a new ultrasonic-assisted semi-solid brazing on dissimilar Al/Mg alloys

In this work, an ultrasonic-assisted semi-solid brazing method was proposed to join Al/Mg. Oxide films on substrate surfaces can be successfully removed even when filler metal was at semi-solid state. A large quantity of intermetallic compounds (IMCs) formed at 460 °C because of large amount of Al and Mg dissolved into joint caused by strong cavitation. Decreasing the temperature to 430 °C could significantly reduce IMC. However, weak cavitation happened inside low liquid phase fraction at 420 °C, making it difficult to break IMCs and solid phases.