Interface diffusion studies in composites of continuous SiC and B4C-B fibers in a titanium metal matrix

Interface diffusion interactions between a sulfur environment and both SiC-(Ti-6Al-4V) and B4C-B fiber-(Ti-6Al-4V) reinforcement-matrix interfaces are studied, in order to establish the character of interface modifications due to thermal cycling treatments in the 25-550 C range and isothermal treatments at 550 C. It is noted that the diffusion along the interface was enhanced under thermal cycling conditions. In addition to diffusion down the interface, diffusion into the matrix was studied with combined scanning Auger microscopy and inert ion sputtering. The rapid diffusion along the boundary was separated from the slow diffusion into the bulk. The sulfur diffusion rate along the interface was much higher than that into the bulk.