Chapter 65. Tensile Stress-Rupture of Sic\Sic Minicomposites in Vacuum

  1. Mrityunjay Singh and
  2. Todd Jessen
  1. J. Martínez Fernández1 and
  2. G. N. Morscher2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470294680.ch65

25th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 22, Issue 3

25th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 22, Issue 3

How to Cite

Martínez Fernández, J. and Morscher, G. N. (2001) Tensile Stress-Rupture of Sic\Sic Minicomposites in Vacuum, in 25th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 22, Issue 3 (eds M. Singh and T. Jessen), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294680.ch65

Author Information

  1. 1

    Dpto. de Física de la Materia Condensada University of Seville, Spain

  2. 2

    Ohio Aerospace Institute NASA Glenn Research Center, MS 106-5 Cleveland, OH

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2001

ISBN Information

Print ISBN: 9780470375730

Online ISBN: 9780470294680

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Keywords:

  • minicomposites;
  • rupture;
  • vacuum;
  • mechanisms;
  • oxidation

Summary

Single tow Hi-NicalonTM, fiber-reinforced CVI SiC matrix minicomposites with C and BN interphases were tested in tension (constant load) at temperatures from 700°C to 1200°C in vacuum. The minicomposites were precracked at room temperature based on acoustic emission to ensure significant matrix cracking had occurred. The stress-rupture properties were compared with those in air. The stress-rupture properties were superior in vacuum than in air for all temperatures and loads. Little rupture strength degradation occurred at 700°C or 950°C in vacuum in contrast to in air where oxidation induced strength degradation had been observed. At 1200°C the differences in rupture strengths in vacuum and in air were less significant because minicomposite failure was dominated by the creep properties of the fibers. For temperatures above 1050°C there was a significant amount of “etching” of the CVI SiC matrix due to the sublimation of Si in Si-rich regions of the SiC.