Transient liquid phase (TLP) bonding of Ti2AlNb alloy using Ti/Ni interlayer: Microstructure characterization and mechanical properties

• TLP bonding of Ti2AlNb alloy using Ti/Ni interlayer was achieved.
• Effect of bonding parameter on joint microstructure and strength was studied.
• TLP bonded Ti2AlNb joints had excellent high-temperature strength.
• E and H of reaction phases in the joint were determined by nano indentations.

A reliable Ti2AlNb alloy joint was successfully obtained by transient liquid phase (TLP) bonding technique using Ti/Ni interlayer. The effects of bonding temperature and time on the interfacial microstructure and mechanical properties of the TLP bonded Ti2AlNb joints were investigated. The results showed that the joint was primarily comprised of two characteristic zones, and the reaction phases formed in the bonded joint were Nb3Al, B2, τ3 and Ti2Ni. The maximum shear strength at room temperature reached 428 MPa when the joint was bonded at 1180 °C for 20 min, while it was 423 MPa, 407 MPa and 338  MPa at 500 °C, 650 °C and 800 °C, respectively. Elastic modulus (E) and hardness (H) of the reaction phases were determined by nano indentations. The formation of τ3 phase was extremely hard and brittle, which provided a preferential path for crack initiation and propagation.