Transient liquid phase diffusion bonding of Ti–24Al–15Nb–1Mo alloy to TiAl intermetallics

Abstract Transient liquid phase (TLP) diffusion bonding of a Ti 3 Al-based alloy and TiAl intermetallics was firstly conducted with Ti–15Cu–15Ni (wt%) interlayer. Ti 2 Al layer, α 2 -Ti 3 Al band, Ti-rich phase, Ti 2 Ni and Ti 2 Cu compounds were formed within the joint and the joint showed a low shear strength of 74–79 MPa. For the newly designed Ti–Zr–Cu–Ni–Co system filler alloy, the bonded joint mainly consisted of Ti-rich phase, Ti 2 Al layer, (Ti, Zr) 2 Al phase and (Ti, Zr) 3 Al dissolved with Cu, Ni and Co. The joints bonded at 1253 K for 600 s with a pressure of 2 MPa presented the maximum shear strength of 435 MPa at room temperature, and the strength of 234 MPa was maintained at 873 K. CuZr and Zr 2 Ni phases rather than Ti 2 Ni and Ti 2 Cu compounds were formed within the latter joint. The formation of the CuZr and Zr 2 Ni phases as well as the plastic α-Ti phase increased the joint ductility to a great extent.