Development of Low-Melting Ti-Zr-Base Alloys for Brazing of Titanium

Ternary or quaternary Ti-Zr-rich alloys whose liquidus is below the alpha/beta transus temperature of titanium have the potential of forming strong braze joints between CP titanium as well as between titanium alloy components.  Coarsening of the microstructure is minimized. Bond strengths rival those of the base materials. We report on alloys with eutectic and near eutectic compositions that can wet and bond diverse base materials.  After additional forming and/or diffusion heat treatment the microstructure in the bond layer that is close to that of the (fine-grained) base material.  Applications are envisaged for the fabrication of complex structures, such as heat exchangers from thin-walled sheet or tubular components, the joining or repair of Ti-castings and the fabrication of structures of complex geometry.