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 degrees 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.