Diffusion bonding of Ti₃AlC₂ ceramic via a Si interlayer

Based on the structure characteristic of Ti3AlC2 and the easy formation of Ti3Al1 -x Si (x) C-2 solid solution, a Si interlayer was selected to join Ti3AlC2 layered ceramic by diffusion bonding method. Joining was performed at 1,300-1,400 degrees C for 120 min under 5 MPa load in an Ar atmosphere. The phase composition and interface microstructure of the joints were investigated by XRD, SEM and EPMA. The results revealed that Ti3Al(Si)C-2 solid solution formed at the interface. The mechanism of bonding is attributed to silicon diffusing inward the Ti3AlC2. The strength of joints was evaluated by a 3-point bending test. The jointed specimens exhibit a high flexural strength of 285 +/- 11 MPa, which is about 80% of that of the Ti3AlC2; and retain this strength up to 1,000 degrees C. The high mechanical performance of the joints indicates that diffusion bonding via a Si interlayer is effective to bond Ti3AlC2 ceramic.