Influence of Orientation Angle of Fiber on Mechanical Properties in Uni-Directional and Two-Directional Carbon Fiber Reinforced SiC Composites

Uni-directional and two-directional carbon fiber reinforced SiC composites (here in after referred as UD-Cf/SiC and 2D-Cf/SiC, respectively) were fabricated by hot pressing method to investigate the influence of fiber orientation angle (θ) to applied load direction on flexural strength and fracture toughness. (1) The UD-Cf/SiC composite with θ=0° showed highest strength and highest fracture toughness. They were 950MPa at room temperature, 1050MPa at 1450°C and 30MPa⋅m1/2, respectively. (2) The flexural strength of UD-Cf/SiC composites with θ=θ° were estimated by using flexural strengths of UD-Cf/SiC composites with θ=0° and θ=90° and “Tai-Hill Theory”. (3) Flexural strength and fracture toughness of 2D-Cf/SiC composites with the orientation angle of +θ/-θ/+θ/-θ… were higher than those of UD-Cf/SiC with the same orientation angle of +θ/+θ….