Chapter 68. Notched Fracture Behavior of Oxide/Oxide Nextel(tm)720/AS Composite

  1. Todd Jessen and
  2. Ersan Ustundag
  1. Dennis J. Buchanan1,2,
  2. Reji John1 and
  3. Larry P. Zawada1

Published Online: 26 MAR 2008

DOI: 10.1002/9780470294628.ch68

24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 21, Issue 3

24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 21, Issue 3

How to Cite

Buchanan, D. J., John, R. and Zawada, L. P. (2000) Notched Fracture Behavior of Oxide/Oxide Nextel(tm)720/AS Composite, in 24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 21, Issue 3 (eds T. Jessen and E. Ustundag), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294628.ch68

Author Information

  1. 1

    Materials and Manufacturing Directorate, Air Force Research Laboratory (AFRL/MLLN), Wright-Patterson Air Force Base, OH 45433-7817

  2. 2

    University of Dayton Research Institute, Dayton, OH 45419

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2000

ISBN Information

Print ISBN: 9780470375686

Online ISBN: 9780470294628

SEARCH

Keywords:

  • ceramic fibrous monoliths;
  • alumina composites;
  • oxidation;
  • hot-pressing process;
  • residual compressive stresses

Summary

Oxide/oxide ceramic matrix composites (CMC) are currently being demonstrated in high-temperature aerospace applications where their beneficial resistance to oxidation is critical to a successful design. Many of these component applications require holes and notches for cooling and attachment points. An investigation on the effects of notches on the fracture strength and damage at room and elevated temperature was initiated. The oxide/oxide CMC studied during this investigation was Nextel(tm)720/AS. The Alumina-Silica matrix was reinforced with an eight-harness satin weave (8HSW) mat of Nextel(tm)720 fibers. Two double-edged notch-geometries were studied, semi-circular and sharp (saw-cut) notches. Strain gages, extensometry and fractured samples were used to characterize the damage zone in the vicinity of the notches. Nextel(tm)720/AS composite exhibited notch insensitive behavior for a range of tip radii and temperatures. Only at temperatures ≥1100°C did the Nextel(tm)720/AS CMC show any observable notch sensitivity. Finite element predictions of stress-strain behavior at the notch tip showed good agreement with the measured strain gage data.