Understanding the oxidation behavior of TiAl alloy joints brazed using Ti and Ni based filler

Vacuum brazing of TiAl alloy is achieved using TiZrNiCu fillers and BNi-2 fillers. The oxidation behavior of the two kinds of TiAl alloy joints is investigated in air at 800 °C. The influence of high-temperature oxidation on the microstructure and mechanical properties of the joints are characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and shear tests. It is found that long-term oxidation does not have a large effect on the microstructure of joints. However, the fillet of the brazed joint achieved via BNi-2 fillers forms longitudinal solidification cracks, which proved that the brazed joint using TiZrNiCu fillers shows more excellent oxidation resistance.