Journal of Inorganic Materials

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Failure Mechanism of C/SiC Composites under Stress in Oxidizing Environments

LIU Xiao-Ying, ZHANG Jun, ZHANG Li-Tong, XU Yong-Dong, LUAN Xin-Gang   

  1. National Key Laboratory of Thermostructure Composite Materials, Northwestern Polytechnical University, Xi'an 710072, China
  • Received:2005-08-28 Revised:2006-01-03 Published:2006-09-20 Online:2006-09-20

Abstract: Stressed oxidation testing on C/SiC composites in dry and wet oxygen environments under cyclic and constant stress was conducted in the present study. Experimental results and microstructures of fracture surfaces analyzed
by SEM show that the C/SiC composites have a better oxidation resistance
and a longer life under fatigue testing than under creep testing. In dry oxygen environment, the failure of C/SiC composites under creep testing is mainly due to the oxidation of carbon fibers. While in wet oxygen ambient, the fracture of C/SiC composites under creep testing is caused by the failure of SiC matrix because the water vapor accelerates the oxidation of SiC.

Key words: C/SiC, fatigue, creep, oxidation

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