Microstructure–properties relationship of TLP-bonded GTD-111 nickel-base superalloy

Relationship between microstructure and mechanical properties of transient liquid phase-bonded joints of GTD-111 nickel-base superalloy using a Ni–Si–B interlayer was investigated. Shear strength and hardness profile of the joints were discussed with respect to the bond microstructure. In the bonding condition, in which isothermal solidification has not been accomplished completely, eutectic constituent which has the highest hardness in the bond region is the preferential failure source. Additionally, it was found that when isothermal solidification is completed, the extent of γ′ formation in the bond region is the controlling factor for joint strength. Shear strength of bonds after post-bond heat treatment was close to that of the base metal.