Wide gap transient liquid phase bonding of NiAl-Hf to a nickel base superalloy

Conventional transient liquid phase (TLP) bonds between the structural inte rmetallic compound NiAl and nickel base superalloys suffer from the formati on, during bonding, of undesired stable second phases. The present paper in vestigates the extent to,which this problem can be overcome by the use of a wide gap TLP bonding process, employing composite interlayers. The paper c onsiders TLP bonding of single crystal NiAl-Hf to ii polycrystalline supera lloy Martin-Marietta (MM) 247 by means of an NiAl-Cu composite preform. The paper contrasts the relative influence of the TLP process and post-bond he at treatment on joint microstructure.