Solid-state joining of SiC using a thin Ti3AlC2, TiC, or Ti filler

Abstract

SiC monoliths containing 5 wt.% Al2O3-Y2O3 additive were joined using a thin Ti3AlC2, TiC, or Ti filler. After joining at 1900 °C for 5 h under 3.5 MPa, the joint properties were compared in terms of the microstructure, phase evolution, joining strength, and possible elimination of the joining layer. Although all samples showed a sound joint, the microstructure differed according to the filler. SiC joined with Ti3AlC2 filler showed an indistinguishable joining interface due to the filler decomposition followed by solid-state diffusion into the SiC base, whereas TiC filler remained at the interface without showing decomposition or diffusion. In contrast, the Ti filler showed a possible elimination of the joining layer because of the diffusion of Ti and the formation of TiC. The mean joining strengths for the Ti3AlC2, TiC, and Ti fillers were 300, 234, and 248 MPa, respectively, which were comparable to that of the base SiC material (250 MPa).