SiC ceramics joined with an in-situ reaction gradient layer of TiC/Ti3SiC2 and interface stress distribution simulations

A new multi-layered design of joining filler, consisting of a Ti3SiC2 layer and an in-situ reaction TiC transition layer, was proposed to join monolithic SiC. The robust TiC transition layer was formed in-situ by controlling the interface reaction and diffusion process between the deposited Ti layer and the SiC matrix. The joining process was evaluated by the analysis of the interface reaction, phase evolution, mechanical properties, and finite element analysis. The bending strength of the sample joined at 1500 degrees C was 155.8 +/- 23.1 MPa, which was similar to that of the reference unjoined SiC (155.1 +/- 35.6 MPa). The thermal residual stresses between SiC and Ti3SiC2 were released by the formation of gradient layer of TiC at the interface. When the optimized joining approach was used, a dense TiC transition layer was formed and all brittle Ti-Si intermetallic phases completely transformed to Ti3SiC2. Furthermore, the proposed multi-layer joining design shows its potential to be used for joining of SiC-based ceramic matrix composites.