Failure Analysis of Nextel™ 720 Fibers Subjected to High-Temperature Testing: The Role of Intrinsic Fiber Impurities

  1. Dr. W. Krenkel2,
  2. Prof. Dr. R. Naslain3 and
  3. Prof. Dr. H. Schneider4
  1. W. Braue1,
  2. R. Borath1,
  3. F. Flucht1,
  4. J. Goering1 and
  5. Prof. Dr. H. Schneider4

Published Online: 13 JAN 2006

DOI: 10.1002/3527605622.ch16

High Temperature Ceramic Matrix Composites

High Temperature Ceramic Matrix Composites

How to Cite

Braue, W., Borath, R., Flucht, F., Goering, J. and Schneider, H. (2001) Failure Analysis of Nextel™ 720 Fibers Subjected to High-Temperature Testing: The Role of Intrinsic Fiber Impurities, in High Temperature Ceramic Matrix Composites (eds W. Krenkel, R. Naslain and H. Schneider), Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, FRG. doi: 10.1002/3527605622.ch16

Editor Information

  1. 2

    Deutsches Zentrum für Luft- und Raumfahrt e.V., Institut für Bauweisen- und Konstruktionsforschung, Pfaffenwaldring 38–40, 70569 Stuttgart, Germany

  2. 3

    Université de Bordeaux, Laboratoire des Composites Thermostructuraux, 3, Allée de la Boétie, 33600 Pessac, France

  3. 4

    Deutsches Zentrum für Luft- und Raumfahrt e. V., Institut für Werkstoff-Forschung, Linder Höhe, 51147 Köln, Germany

Author Information

  1. 1

    German Aerospace Center (DLR), Materials Research Institute, D-51147 Cologne, Germany

  2. 4

    Deutsches Zentrum für Luft- und Raumfahrt e. V., Institut für Werkstoff-Forschung, Linder Höhe, 51147 Köln, Germany

Publication History

  1. Published Online: 13 JAN 2006
  2. Published Print: 12 OCT 2001

ISBN Information

Print ISBN: 9783527303205

Online ISBN: 9783527605620

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Keywords:

  • high temperature ceramic matrix composites;
  • Nextel 720;
  • failure analysis;
  • high-temperature testing;
  • influence of intrinsic fiber impurities

Summary

Catastrophic failure of Nextel™ 720 fibers upon annealing at T ≥ 1300°C is investigated via optical and electron microscopy focussing on the role of intrinsic fiber impurities on different dimensional scales of the microstructure. Fiber degradation is related to intrinsic Ca-rich particles embedded into the surface of the as-received fiber. Contrary to these local defects, interaction of fiber impurity sources with dynamic fatigue testing is controlled by the average impurity level throughout the fiber bulk effective on a much lower concentration level. The possible existence of a non-crystalline phase acting as an impurity sink and a fast diffusion path during high-temperature deformation of Nextel™ 720 fibers is discussed.