Evolution of the interlayer microstructure and the fracture modes of the zirconia/Cu–Ag–Ti filler/Ti active brazing joints

Zirconia (3Y-PSZ) and titanium were joined by active brazing in vacuum with the 63 Ag–35.25 Cu–1.75 Ti (wt.%) filler at 840–870 °C under different contact loads. Brazing conditions did not affect noticeably the joint mechanical strength but a remarkable change of the interlayer microstructure was found. This microstructure evolution affected the fracture behavior: ductile fracture through the Ag-rich area changed to a brittle one through the intermetallic area in the titanium–filler interface after brazing with long soaking at maximum temperature.