Comparisons of cyclic fatigue hysteresis between C/SiC and SiC/SiC ceramic–matrix composites with different fiber preforms at room and elevated temperatures

In this paper, the cyclic fatigue hysteresis of carbon fiber reinforced silicon carbide (C/SiC) and SiC/SiC ceramic–matrix composites with different fiber preforms at room and elevated temperatures is investigated. The evolution of fatigue hysteresis dissipated energy versus applied cycle number for unidirectional C/SiC (σ_max = 240 MPa at room temperature and σ_max = 250 MPa at 800℃ in air atmosphere), cross-ply C/SiC (σ_max = 105 MPa at room temperature and 800℃ in air atmosphere), 2D C/SiC (σ_max = 387 and 425 MPa at room temperature), 2.5D C/SiC (σ_max = 180 MPa at room temperature, σ_max = 140 MPa at 800℃ in air atmosphere, and σ_max = 230 MPa at 600℃ in inert atmosphere), 2D SiC/SiC (σ_max = 130 MPa at 600℃, 800℃, and 1000℃ in inert atmosphere, σ_max = 80 MPa at 1000℃ in air atmosphere, σ_max = 100 MPa at 1000℃ in steam atmosphere, σ_max = 140 MPa at 1200℃ in air and in steam atmospheres, σ_max = 90, 120 MPa at 1300℃ in air atmosphere), and 3D SiC/SiC (σ_max = 100 MPa at 1300℃ in air atmosphere) is analyzed. The change rate of the fatigue hysteresis dissipated energy between C/SiC and SiC/SiC composites is compared. The fatigue hysteresis dissipated energy decreases with applied cycle number for unidirectional, and cross-ply C/SiC composite at 800℃ in air, and 2.5D C/SiC composite at 600℃ in inert; and the fatigue hysteresis dissipated energy increases with applied cycle number for 2.5D C/SiC composite at 800℃ in air, 2D SiC/SiC composite at 600℃, and 800℃ in inert.