Low cycle fatigue behavior of a 3D braided KD-I fiber reinforced ceramic matrix composite for coated and uncoated specimens at 1100°C and 1300°C

Stress-controlled low cycle fatigue tests of a three-dimensional KD-I fiber reinforced ceramic matrix composites were conducted with a sine wave form at 1100. °C and 1300. °C in air. Fatigue stress level ranged from 40. MPa to 136. MPa. The influences of temperature, coating and loading frequency on fatigue performance were considered. The strain ratcheting and modulus drop were observed, and their relation with damage evolution and ultimate failure were studied. Damage and failure mechanisms were also investigated. Oxidation embrittlement controlled the damage and failure of the composites in fatigue tests.