Tensile properties of a SiCf/SiC composite

This work examines the mechanical behavior of a 2D woven, 0-90 SiC fiber-reinforced SiC matrix composite. Tensile experiments show that the short-term behavior is largely independent of test temperature below 1000 degrees C. Microscopic examination reveals that the extent of fiber pull-out and the integrity of the remaining material are also independent of temperature in this range. Conversely, at 1200 degrees C, the material retains much of its low-temperature stiffness and proportional limit, while the strength increases substantially. Micrographs of these specimens reveal little individual fiber pull-out and a higher density of matrix microcracks. Room-temperature tensile data show that the mechanical behavior is rate-dependent; higher strain rates lead to a lower Young's Modulus, higher proportional limit and higher ultimate strength. In-plane shear experiments demonstrate that the unreinforced matrix strength is approximately 10% of the composite tensile strength.