Fabrication and Mechanical Properties of 3-Dimensional Tyranno Fiber Reinforced SiC Composites by Repeated Infiltration of Polycarbosilane

Three-dimensional Tyranno fiber reinforced SiC composites were fabricated by repetitive infiltration of molten polycarbosilane into 3-dimensional textile preforms (volume fraction 35-39%) with different fiber orientation ratio, followed by a pyrolysis process up to 1200°C in flowing argon. The composites displayed both high fracture toughness and work of fracture. In addition, a semistable fracture behavior was maintained even at 1200°C in air. Bending strength, fracture toughness, and work of fracture of the composite were strongly affected by the fiber orientation ratio and fiber diameter of the preform. This study suggested that the volume fraction of fiber along the tensile direction was the critical parameter for increasing the mechanical properties of the composite, and that the use of thin fibers involved higher values of work-of-fracture.