Crack propagation modes of textured interphase in C/SiC composite

The fracture process analysis of textured interphase in fiber-reinforced ceramic-matrix composites (CMCs) is a challenging task. In this paper, the crack formation, propagation and evolution of textured PyC interphase in C/SiC composites were experimentally and theoretically investigated. The C/SiC minicomposites containing three different textured PyC interphase, i.e., high-textured (HT), low-textured (LT) and hybrid LT/HT, were designed and fabricated, and the characteristics of interphase cracks were observed under the SEM. A phase-field model (PFM) for finite thickness textured interphase was proposed to predict the crack deflection, propagation, and evolution. The experimental observations and simulations showed that the single LT-PyC interphase serves as the main crack propagation region, effectively inducing crack deflection by array crack nucleation, merger, and propagation. In addition, As the interphase fracture toughness and modulus increase, there are three cases of the crack propagation in interphase, that is, array crack nucleation inside the interphase, short debonding at the interphase/fiber interface, and cracks penetration directly, which enriched understanding of the relationship between interphase properties and crack propagations.