Residual thermal stress of SiC/Ti3SiC2/SiC joints calculation and relaxed by postannealing

Residual thermal stresses in SiC/Ti3SiC2/SiC joining couples were calculated by Raman spectra and simulated by finite element analysis, and then relaxed successfully by postannealing. The results showed that the thermal residual stress between Ti3SiC2 and SiC was about on the order of 1 GPa when cooling from 1300 degrees C to 25 degrees C. The thermal residual stresses can be relaxed by the recovery of structure disorders during postannealing. When the SiC/Ti3SiC2/SiC joints postannealed at 900 degrees C, the bending strength reached 156.9 +/- 13.5 MPa, which was almost twice of the as-obtained SiC/Ti3SiC2/SiC joints. Furthermore, the failure occurred at the SiC matrix suggested that both the flexural strength of joining layer and interface were higher than the SiC matrix.