A study on transient liquid phase diffusion bonding of Ti-22Al-25Nb alloy

Transient liquid phase diffusion bonding of Ti-22Al-25Nb (at.%) alloy with Ti-15Cu-15Ni (wt.%) was performed. The factors influencing the microstructure and strength of the joints were studied. A suitably long holding time and high bonding temperature would benefit the formation of joints with homogeneous compositions and high strength. Nb element is the mainly controlling one to the formation of composition-homogenous bonding zone. The bonding zone of joint with a rapid cooling technology after dwelling at bonding temperature is composed of B2 phase. Slow cooling technology is beneficial to improving the joint strength. The tensile strength at room temperature of the joint under the joining conditions of bonding temperature 970 °C for 90 min with a slow cooling technology reaches up to 1018 MPa, which is equal to 93% of base material tensile strength, obviously higher than the joint strength of 931 MPa with a rapid cooling technology.