Transient Liquid Phase Bonding of NiAl Intermetallic Compound to Nickel-Base Superalloys - A Microstructural Investigation

摘要

An investigation of the joining of NiAl to nickel-base superalloys is presented in this paper. The paper concentrates on the transient liquid phase (TLP) bonding process. The joining of both single-phase, binary, poly-crystalline NiAl and a multiphase, single-crystal NiAl-Hf alloy is considered. Cast, polycrystalline Martin Marietta 247 is employed as a "typical" #gamma# / #gamma#' superalloy. The paper examines the use of both conventional 50 #mu#m copper interlayers and 175 #mu#m composite interlayers employing an NiAl - Cu preform. The paper contrasts microstructural development in these systems. In particular, the paper considers the formation of undesired second phases (such as #sigma# and/or carbides) in the diffusion affected portion of the superalloy.