Ultrasonic spot welding of Al sheets by enhancing the temperature of weld interface

•USWed Al/Al joints with and without interlayer has been successfully fabricated.•Effect of interlayer on the temperature of weld interface was illustrated.•The weldability and mechanical properties for the joint with interlayer were improved. Ultrasonic spot welded Al/Al joints with Al2219 particle interlayer for enhancing the temperature of the weld interface were successfully conducted. The results indicate that Al2219 particle interlayer is beneficial to the increase of temperature at the weld interface, and the increased temperature further facilitates the weldability of Al/Al joints. Meanwhile, no unbonded regions are discovered, and the combination of Al/interlayer interface is high close. The peak tensile shear load of ∼5.47kN is achieved for the joint with Al2219 particle interlayer, which is 35.7% higher than that (∼4.03kN) for the joint without Al2219 particle interlayer.