Preliminary Investigation on Brazing Performance of Ti/Ti and Ti/Steel Joints Using Copper Film Deposited by PVD Technique

Microstructural aspects and bonding characteristics of vacuum brazed Ti/Ti and Ti/steel were investigated. A thin-copper film, with different thicknesses, was deposited on the brazed metals by physical vapor deposition technique to serve as a brazing filler metal. Test joints were processed at a temperature of 910 °C and 15 min holding time. The resultant joints were characterized to determine the brittle intermetallic compound in the interfacial layer and the shear strength of the joints were tested. Our preliminary experimental results showed that sound joints with a good wetting quality, lack of pores and cracks can be achieved. Intermetallic phases such as Ti₂Cu, TiCu, FeTi, and Fe₂Ti were predicted from the chemical analyses. The Ti/Ti joints achieved a higher shear strength than the Ti/steel joints and there is a tendency for the tension shear strength to increase when a thick Cu-deposited layer is used.