Mechanical and thermal properties of 2D and 3D SiC/SiC composites

SiC fiber-reinforced SiC composites (SiC/SiC), whose preforms had 3D satin weave or 2D non-woven fabric, were fabricated by chemical vapor infiltration (CVI) or polymer impregnation and pyrolysis (PIP). The 3D satin texture made from Hi-Nicalon Type S fiber was successfully woven although the fiber has high elastic modulus. Both CVI and PIP SiC/SiC composites of Type S fiber had higher thermal conductivity than those of Hi-Nicalon fiber. These results can be ascribed to higher thermal conductivity of Type S fiber. The thermal conductivity of the 3D PIP SiC/SiC composites was increased after annealing at 1400°C in vacuum. The bend strength of the 2D CVI SiC/SiC composites of non-coated Hi-Nicalon fiber was higher than that of non-coated Type S fiber, indicating that interfacial modification for Type S fiber is needed to obtain good mechanical properties.