The effect of specimen cross-sectional area on the strength and toughness of two-dimensional C/SiC composites

The current work investigates the effect of specimen cross-sectional area on the strength and toughness of two-dimensional carbon fiber-reinforced SiC matrix composites (C/SiC). Three types of C/SiC specimens with varying cross sections were fabricated by chemical vapor infiltration followed by heat treatments at 1500 °C and 1900 °C. Dogbone composite specimens were tested in tension for the determination of tensile strength, fracture toughness and elastic modulus. Results showed that, as specimen cross-sectional area decreased, fracture toughness and elastic modulus increased while tensile strength increased only marginally. Heat treatment was found to limit the effect of cross-sectional area on the tensile strength and elastic modulus of the C/SiC composites.