Micromechanics Interface Damage of Ceramic-Matrix Composites Under Cyclic Fatigue at Elevated Temperature

In this chapter, the interface damage in fiber-reinforced ceramic-matrix composites (CMCs) under cyclic fatigue loading at elevated temperatures was estimated through hysteresis loops. Based on the damage mechanisms of fiber slip relative to matrix in the interface debonding region, the micromechanics fatigue hysteresis loops models considering different interface slip cases were developed. The fatigue hysteresis dissipated energy for the strain energy lost per volume during corresponding cycle was formulated in terms of the interface shear stress. The values of the interface shear stress of 2D woven and 3D braided SiC/SiC composites at 600, 800, 1000, 1200, and 1300 °C in inert, air, and steam conditions were estimated. Effects of temperature, oxidation, and fiber preforms on the degradation rate of the interface shear stress versus the cycle number were analyzed.