Transient liquild phase diffusion bonding processing of Ni₃Al single crystal superalloy

By using KNi₃ alloy as filler,Ni₃Al single crystal superalloy were bonded through transient liquid phase bonding method.The changes of the microstructures of the bonded joints and the base metal in different holding time were analyzed.The mechanical properties of the bonded joints were tested.The results show that,for the TLP diffusion bonding joint at 1 240℃ for 12 h,a majority area of TLP bonding joint is the same as the matrix which consists of γ and γ'phases.Other area consists of the γ+γ'eutectic phase and small block borides.γ'phase of base metal changes from largely cuboidal to irregular shape.Stress rupture strength of the TLP bonding joints at 1 000℃ reaches 90% of those of the standard base metal.During stress rupture,γ'phase rafted in bonding area were coarsening and irregular,which had some angles with the direction of stress rupture.