TEMPERATURE, STRAIN RATE AND FIBER ORIENTATION EFFECTS IN THE COMPRESSIVE FRACTURE OF SIC FIBER-REINFORCED GLASS-MATRIX COMPOSITES

Continuous SiC fiber-reinforced glass-matrix composites have been tested in compression over a wide range of temperatures and loading rates. Both uniaxial and cross-plied fiber orientations were studied. Strength is found to depend sensitively on orientation and loading rate, while temperatures up to 800 degree C have less effect. Orientation effects are explained in terms of matrix microfracture and fiber buckling. The latter are also shown to control strengthening at very high strain rates, where it is hypothesized that strength is enhanced by inertial effects which inhibit the development of the localized pockets of intense matrix microfracture and general buckling required for the nucleation of fiber kinks.