Processing of composites in the Ti-Si-C system

New composites utilizing Ti3SiC2 as the matrix phase have been synthesized. The thermal and kinetic aspects of the phase formation in the Ti-Si-C syst em were examined. Standard dry powder processing techniques, pressureless s intering and hot pressing (both under inert atmosphere) were employed to pr ocess the sample materials. The phase identification was performed by X-ray powder diffraction (XRPD) analysis. The ratio of the volume fractions of t he reinforcement phases SiC and/or TiCx to the matrix phase Ti3SiC2 have be en measured and tailored over a wide range by means of controlling the stoi chiometry of the starting elemental powders and varying the heat treatment. It was found that the Si tends to evaporate at elevated temperatures durin g sintering. The loss of Si is the likely reason why it is difficult to for m the single phase Ti3SiC2. Incorporating this observation into the composi te formation, a method to form in-situ composites is proposed. The volume f raction of the constituent phase in the composite can be controlled by vary ing the processing parameters. (C) 2001 Kluwer Academic Publishers.