Temperature-dependence of mechanical properties of Si-Ti-C-O fiber-bonded ceramic

Temperature-dependence of various mechanical properties of Si-Ti-C-O fiber- bonded ceramic is investigated. The material was produced by hot-pressing t he laminae of oxidized satin-woven Si-Ti-C-O fibers, and then showed very h igh fiber-volume fraction (around 0.85) and very little porosity, compared with ordinary ceramic matrix composites. The in-plain tensile, compressive and inter-laminar shear strengths of the material at room temperature were maintained up to 1400 degreesC, whereas the Young's modulus and the compres sive strength of out-plain direction (transverse direction) decreased at 14 00 degreesC. The behavior toward the tensile and inter-laminar shear streng ths were in good agreement with the changes in fiber pull-out length and de laminating position, respectively. A buckling of the fibers parallel to the stress axis and a large deformation of the specimen were observed in the f racture surface after compression tests of in- and out-plain directions at 1500 degreesC, respectively. From the differences in the mechanical propert ies and fracture morphologies, it was concluded that the change in the frac ture strength at the high temperature was caused by softening of the amorph ous SiO2 phase.