Joining of Titaniumu Using Ag-Cu Alloy Thin Film Deposited on Bonding Surface with Ion Beam Sputtering
Akio Hirose, Makoto Nojiri, Hitotaka Ito and Kojiro F.Kobayashi
Abstract:A novel bonding process, which is a kind of diffusion bonding with cleaning the bonding surface followed by deposition of Ag-28mass%Cu alloy thin layer using ion beam sputtering, was applied to joining of commercial pure titanium (CPTi)under atmospheric pressure. The deposition of the Ag-Cu layer after removing the oxide film of the bonding surface successfully improve bondability of CPTi. The joint strengths depend on the thickness of the Ag-Cu deposited layer. A maximum joint strength close to the base metal strength is obtained using the optimum thickness of Ag-Cu deposited layer, 0.3mm, under the conditions of a bonding temperature of 1153K and bonding time of 300s or more. The thicker Ag-Cu deposited layer of 1.0um in thickness results in a hardened microstructure including Ti2(Cu, Ag)intermetallic precipitates and thereby lower strength and lower ductility after bonding at 1153K for 1800s. The joint with the thinner Ag-Cu deposited layer of 0.1mm in thickness is not bonded at all.