Analysis on high temperature properties of TiAl alloy joints brazd with a Ti-based filler

Vacuum brazing of TiAl alloy with Ti-Zr-Cu-Ni-Co-Mo amorphous filler as interlayer was investigated. The shear strength and tensile strength at high temperature of the joints brazed at 1 000 ℃ for 5 min were studied and was compared with the strength of base metal. Results show that the brazed joints can be used for a long time at 700 ℃, but the shear strength of the joints decreases sharply when the shear testing temperature is higher than 700 ℃ due to the formation of oxide and the change of microstructures in the central zone of brazed joints. The tensile strength of brazed joints and base metal obtained at different tensile testing temperatures decreases with the increasing of testing temperature. The research shows that the gap between brazed joints and base metal decreases first and then increases, and the room temperature performance of brazed joints and base metal can still be maintained above 80% at temperature of not higher than 600 and 800 ℃, respectively.