Effect of Frequency on Fatigue Behavior in 3D-Woven Tyranno Fiber Reinforced SiC Composites
Shijie ZHU, Yohei KANEKO, Yasuo OCHI, Toshio OGASAWARA and Takashi ISHIKAWA
Abstract:The tensile and fatigue tests of 3D-woven Tyranno fiber reinforced SiC matrix composites were conducted at room temperature. The tensile strength was not dependent on loading rate, but the strain at failure increases with a decrease in loading rate from 10 to 0.02 MPa/s. The effect of frequency on fatigue behavior was studied between 20 and 0.02Hz with a sine wave form and a stress ratio of 0.1. It was shown that the fatigue failure was cyclic-dependent between 20 and 0.2Hz, but time-dependent between 0.2 and 0.02Hz. The reduction of Young's modulus and sliding stress of interface during fatigue was analyzed. The cyclic-dependent behavior was dominated by wear of interphase and damage on the surface of Si-Ti-C-O fiber during cyclic loading-unloading. The time-dependent behavior was controlled by stress corrosion cracking of fiber and matrix. Key Words:Ceramic matrix composite, Fatigue damage, Effect of frequency, Crack initiation