Life-Limiting Aspects of an Melt-Infiltrated Silicon Carbide Fiber-Reinforced Silicon Carbide Matrix Ceramic Matrix Composite in Interlaminar Shear at Elevated Temperature

Abstract

Life-limiting behavior of a melt-infiltrated (MI) silicon carbide fiber-reinforced silicon carbide matrix (SiC/SiC) ceramic matrix composite (CMC) was determined under interlaminar shear at 1316 °C in air using double-notch-shear test specimens. The three different shear loading configurations of dynamic fatigue, static fatigue, and cyclic fatigue were employed to assess their individual respective lives. The MI SiC/SiC CMC exhibited low susceptibility to fatigue (“slow crack growth”) regardless of loading configuration. A life prediction model for interlaminar shear in cyclic fatigue was developed based on the fracture mechanics framework. The newly developed cyclic fatigue model as well as the previously developed dynamic and static fatigue models were all in good agreement with the experimental data, indicating that the governing failure mechanism under interlaminar shear was consistent, independent of fatigue loading configuration.