Microstructure Evolution and Mechanical Properties of Cu-Ni-Ti Transient Liquid Phase Bonding for SiC-GH3536 Joints

In this study, transient liquid-phase (TLP) bonding of SiC and GH3536 was employed using Cu80Ti15Ni5 (at%) mixed powder. The melting characteristics of the filler materials were analyzed, and the influence of holding time on the microstructure and mechanical properties of the joints was investigated. The formation mechanism of the joints was also explored. The results indicate that the filler materials completely melted at 970°C. In the liquid filler materials, high-melting-point intermetallic compounds (IMCs) can be formed in situ, thereby consuming the melting-point depressant element Ti. Isothermal solidification of the joints was achieved in a short period, and the joint consists of a Cu(ss) matrix and partial (CuₓNi1-x)2Ti ternary compounds and silicides. Cu(ss) exhibits good plasticity, and the in-situ generated (CuxNi1-x)2Ti helps reduce the coefficient of thermal expansion (CTE) of the joints. Therefore, the joining layer has a beneficial effect in alleviating residual stresses. After holding at 970°C for 15minutes, the maximum shear strength reached 56.25MPa. This work provides a new method for joining SiC ceramics and their composites with nickel-based alloys, offering innovative insights into the bonding of ceramics with metals.