Diffusion bonding of high Nb-content Ti_3Al-based alloy

High vacuum diffusion bonding of Ti-23Al-17Nb alloy was performed using the thermal-mechanical simulator Gleeble 1500D to obtain high-strength joints in a Ti3Al-based alloy.Tests show that large bonding parameters favor interfacial bonding but increase the deformation ratio of the joints and coarsen the B2 matrix phase.The optimal bonding temperature is 980℃,the pressure is 7 MPa and the holding time is 30 min with average joint tensile strengths at room temperature of 921 MPa and at 650℃ of 639 MPa,95% and 91% of the base materials' strengths.Tensile fractures for these joints with small bonding parameters occur at the bonding interface,while joint fractures with large bonding parameters occur in the base materials away from the bonding interface in the quasi-cleavage fracture mode.