Determining the fracture resistance of advanced SiC fiber reinforced SiC matrix composites

Nozawa, Takashi; Kato, Yutai*; Kishimoto, Hirotatsu*

One of the perceived advantages for highly-crystalline and stoichiometric SiC and SiC/SiC composites is the retention of fast fracture properties after neutron irradiation. Specifically, it has been clarified that the maximum allowable stress (or strain) limit seems unaffected in certain irradiation conditions. Meanwhile, understanding the mechanism of crack propagation from flaws is somehow lacking. This study aims to evaluate crack propagation behaviors of advanced SiC/SiC and to provide fundamentals on fracture resistance of the composites to define the strength limit for the practical component design. For those purposes, the effects of irreversible energies related to interfacial debonding, fiber bridging, and microcrack forming on the fracture resistance were evaluated.