Strong bonding of titanium to copper through the elimination of the brittle interfacial intermetallics

The microstructures, interfacial reactions, and bonding strength properties of the Ti–Cu dissimilar joints using a commercially available Ag–28Cu–2Ti filler were studied, particularly as they relate to the role of an Ag barrier layer at the Ti interface. A joint microstructure and interfacial reactions closely related to the formation of brittle interfacial Ti–Cu intermetallics were fully dominated by the presence of the Ag layer at the Ti interface. Reliable Ti(base)/TiAg/Ag/Ag–Cu eutectic/Cu(base) joints without any detrimental Ti–Cu intermetallics were achieved at low brazing temperatures below 810 °C by applying an Ag interlayer of suitable thickness. It was notable that their bonding strengths were strong enough to exceed the strength of a Cu bulk base metal. This research demonstrates the potential application of an Ag interlayer for the reliable Ti–Cu dissimilar joints.