Microstructure and Mechanical Properties of Low Oxygen Content SiC Fibers in Simulated Aeroengine Circumstance

Abstract

The low oxygen content SiC fibers were exposed in simulated aeroengine circumstance of \begin{document}${P_{{{\rm{H}}_2}{\rm{O}}}}:{P_{{{\rm{O}}_2}}}:{P_{{\rm{Ar}}}} = $\end{document}14 kPa \begin{document}$:8$\end{document} kPa \begin{document}$:78$\end{document} kPa at 1200 ℃ for 1-50 h. Performances and structure of the fibers were characterized by element analysis, XRD, SEM and tensile test. The results show that the fibers have higher oxygen content, thicker oxide layer, lower strength compared with the fibers treated in dry air. Cracks and α-SiO2 crystal are more likely to occur in silica layer. The steam in the simulated circumstance can accelerate oxidation and crack formation in silica film.

Keywords

• low oxygen content
• SiC fibers
• aeroengine
• oxide layer
• crystallization