Joining Mg alloys with Zn interlayer by novel ultrasonic-assisted transient liquid phase bonding method in air

• A novel ultrasonic-assisted TLP (U-TLP) bonding method was developed in air.
• Mg alloys were joined by U-TLP method using a pure Zn foil at 370 °C.
• A typical TLP joint could been obtained for a short ultrasonic time of ~120 s.
• The maximum strength of the joint mainly consisting of α-Mg was ~106 MPa.

A novel ultrasonic-assisted transient liquid phase bonding method was developed to joining magnesium alloys with Zn interlayer at 370 °C in air. The influence of ultrasonic time on the microstructure and mechanical property of the joints was investigated. The introducing of ultrasonic into transient liquid phase bonding process showed benefit effects on inducing and promoting the eutectic reaction between Mg and Zn, and also accelerating the isothermal solidification process. The joint shear strength increased nonlinearly with the ultrasonic time lengthened and had a relationship with the thicknesses of the Mg51Zn20 and MgZn intermetallic compound layer, α-Mg(Zn) solid solution layer, and the total joint area. The highest average shear strength of the joints for 120 s ultrasonic time reached to 106.4 MPa, which was nearly equal to the strength of Mg base metal.