Effect of brazing temperature on microstructure and mechanical properties of 2D Cf/SiC and Nb joints brazed with Co-Ti-Nb filler alloy

A novel high-temperature filler alloy, Co42.5Ti42.5Nb15 (at%) developed with which Cf/SiC-Nb joints were successfully obtained at 1553-1613 K for 10 min. The effects of brazing temperature on the microstructure and mechanical properties of the joints were investigated. The results show that the typical Cf/SiC and Nb joint consist of Cf/SiC composite/(Ti,Nb)C reaction layer/(Ti,Nb)2Co layer/Nb[Ti,Co]+(Ti,Nb)Co eutectics with some CoNb4Si compounds/Nb substrates. With increasing the brazing temperature, both the thickness of the reaction layers and the content of CoNb4Si in the brazing layer increased, whereas the thickness of the brazing layer reduced. The shear strength presented a peak value of 187 MPa from a brazed at 1593 K.