Transient liquid phase bonding of TiAl and Inconel 718

Ti foil combined with Cu or Ni foils was used as insert metals to join TiAl intermetallic and Inconel 718 employing transient liquid phase (TLP) bonding technique. The effect of dwell time at bonding temperature on the interfacial structures of the joints was investigated. Results showed that defect-free joints was fabricated, but the liquid formation processes and mechanism of Ti-Cu and Ti-Ni insert metals were quite different. Some sublayers were found in the joined zone because the alloyed elements which diffused from Inconel 718 alloy segregated at the interface between Inconel 718 alloy and joined zone. Morphologies and hardness profiles of the joined zones show that the joint produced using Ti-Ni insert metals could isothermally solidify much faster than that produced using Ti-Cu insert metals under the experimental conditions.