Chapter 46. Abradability Testing of Bn-Nextel™ 312/Blackglas™ 3-D Woven Composites and the Effect on Retained Strength

  1. John B. Wachtman Jr.
  1. Durell Wildman1 and
  2. Pramod Khandelwal2

Published Online: 28 MAR 2008

DOI: 10.1002/9780470314876.ch46

Proceedings of the 20th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - B: Ceramic Engineering and Science Proceedings, Volume 17, Issue 4

Proceedings of the 20th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - B: Ceramic Engineering and Science Proceedings, Volume 17, Issue 4

How to Cite

Wildman, D. and Khandelwal, P. (1996) Abradability Testing of Bn-Nextel™ 312/Blackglas™ 3-D Woven Composites and the Effect on Retained Strength, in Proceedings of the 20th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - B: Ceramic Engineering and Science Proceedings, Volume 17, Issue 4 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314876.ch46

Author Information

  1. 1

    Allison Advanced Development Company P.O. Box 7162, Speed Code X12A Indianapolis, IN 46206-7162

  2. 2

    Allison Engine Company P.O. Box 420, Speed Code W05 Indianapolis, IN 46206-0420

Publication History

  1. Published Online: 28 MAR 2008
  2. Published Print: 1 JAN 1996

ISBN Information

Print ISBN: 9780470375433

Online ISBN: 9780470314876

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Keywords:

  • low pressure (LP) turbine interstage seal;
  • thrust turbofan engine;
  • adequate directional structural strength;
  • weight savings;
  • current metal seal

Summary

The low pressure (LP) turbine interstage seal for the Allison Engine Company AE 3007 turbofan engine shown in Figure 1 is the component selected for the Low Cost Ceramic Composite (LC3) program. The AE 3007 engine is a 7200 lb thrust turbofan engine with both military and commercial applications. The goals of the LP turbine interstage seal design are to provide a directly interchangeable design that will meet the 12,000 hours service life requirement with an approximate 74% weight reduction as well as initial acquisition cost and life cycle cost savings.

The current LP turbine interstage seal design is comprised of a Hastelloy X honeycomb compliant seal member brazed to an INCO 718 structural member. Two approaches were used for the ceramic matrix composite (CMC) version of the interstage seal. The first approach entailed developing a process for brazing the Hastelloy X honeycomb material to the CMC with provisions for accommodating the differential thermal expansion ratio of 4:1.

The second approach was to evaluate the abradability/conformability of the CMC material by conducting high speed, high temperature, rub rig testing as well as mechanical testing of the rub specimens to evaluate the retained mechanical strength. In the event the direct rub testing proved to be successful, the need for the Hastelloy X honeycomb and braze joint would be eliminated, resulting in a significant component fabrication cost reduction.