Strength and fracture behavior of diffusion bonded joints

Current high temperature alloy systems for turbines and powerplant heat exchangers are typically titanium-, nickel- or iron-based. The extreme performance environments in these applications demand exacting control of both alloy composition and microstructure. This can be problematic when fabrication or repair requires the joining of multiple parts. Traditional welding processes destroy the desirable microstructure in the region of the weld and may lead to the formation of undesirable phases. Diffusion bonding has been gaining increasing interest in this area as a means of both preserving the joint microstructure and controlling second phase formation. The current paper presents the results of initial experimental studies on diffusion bonding of commercially pure titanium, iron and nickel samples.