Microstructure and Mechanical Properties of Ultrasound-Assisted Soldered Al-50 wt.%Si/Al-27 wt.%Si Joints for Automotive Applications

Hypereutectic Al-27 wt.%Si alloy and hypereutectic Al-50 wt.%Si alloy have been soldered using a Zn-5 wt.%Al interlayer without flux at 420°C in air with ultrasound assistance. The influence of the ultrasound on the migration of Si particles and the microstructure of the solidified Zn-Al-based alloys was investigated. The effect of the distribution of Si particles and the microstructure of the solidified Zn-Al-based alloys on the shear strength is also discussed. As the duration of the ultrasound was increased, the distribution of Si particles became more uniform. The highest average shear strength of the joints reached 70.41 MPa, with fracture mainly occurring at the Si particulate-reinforced Zn-Al-based composite joint.