Microstructure and mechanical property of vacuum brazed TiAl and C/SiC joint

TiAl alloy and C/SiC composites were vacuum brazed with AgCu foils.The formation and evolution of interfacial structure and its effects on shear strength of the joints were studied in this paper.The results showed that the dissolution of TiAl substrate had a strongly effect on interfacial structure.When the brazing temperature was 900℃ for 10 min,AlCu₂Ti blocks accompanied with a small number of AlCuTi and AlCu₄ phases were observed at TiAl side.There were a lot of AgCu eutectic and silver-rich areas close to the composites and TiC reaction layer was formed between C/SiC composite and AgCu eutectic or silver-rich area.Due to the reinforcing effect of the massive AlCu2Ti phases which dispersed in the whole interlayer,the joint shear strength reached 74 MPa when brazing temperature was 900℃ for 25 min.