Degradation of SiC/SiC composite due to exposure at high temperatures in vacuum in comparison with that in air

S. Ochiai, S. Kimura, H. Tanaka, M. Tanaka, M. Hojo, K. Morishita, H. Okuda, H. Nakayama, M. Tamura, K. Shibata, M. Sato

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14 Citations (Scopus)


Room temperature residual strength of the SiC/SiC composite exposed in vacuum at high temperatures (823-1673 K) was studied and compared with that exposed in air. The vacuum-exposed composite showed only the fiber-pullout type fracture, and the pullout length increased with increasing exposure temperature and time, while the fractured mode of the air-exposed one changed with progressing oxidation; from the fiber-pullout type to the nonfiber-pullout one characterized by the overall fracture perpendicular to the tensile axis without fiber-pullout. The reduction in residual strength in the case of vacuum exposure was attributed mainly to the extension of the decomposition-induced defects on the fiber surface into fiber, while that in the case of air exposure mainly to the extension of the crack made by premature fracture of the SiO 2 layer into the fiber. A simple model based on the kinetics of the growth of the defects and fracture mechanics was presented to describe the variation of composite strength as a function of exposure temperature and time for the vacuum exposure, which could describe the experimental results.

Original languageEnglish
Pages (from-to)33-40
Number of pages8
JournalComposites Part A: Applied Science and Manufacturing
Issue number1
Publication statusPublished - Jan 2004
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Mechanics of Materials


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