A high-strength vacuum-brazed TiAl/Ni joint at room temperature and high temperature with an amorphous foil Zr-Al-Ni-Co filler metal

An amorphous Zr58.6Al15.4Ni20Co6 foil was fabricated and applied as the filler metal to vacuum braze TiAl- and Ni-based alloys. The obtained joint has high strength both at room temperature (RT) and high temperature (HT). To investigate the effect of the brazing temperature and holding time on the joint strength, experiments were performed at different temperatures and held for different time. Five different regions derived from the interfacial atomic diffusion and crystallization of the amorphous filler metal were formed after brazing. The energy dispersive spectrometer (EDS) results indicated that sufficient interdiffusion occurred between the filler metal and base alloys after brazing. As a result, fine phases that were different from the base alloys were formed and dispersively distributed in the joint. Shear tests were performed at 30℃ and 600℃ and the results show that the joint strength first increased and then decreased with increases in holding time and heating temperature. The maximum shear strength of the joint at 30℃ and 600℃ were 353 MPa and 214 MPa respectively.