Chapter 69. Study of Crack Development in APS and EB-PVD TBCS with Bending Tests Using Acoustic Emission and In-Situ Visual Observation

  1. Waltraud M. Kriven and
  2. Hua-Tay Lin
  1. R. Herzog,
  2. P. Majerus,
  3. J. Mönch,
  4. R. W. Steinbrech,
  5. F. Schubert and
  6. L. Singheiser

Published Online: 27 MAR 2008

DOI: 10.1002/9780470294802.ch69

27th Annual Cocoa Beach Conference on Advanced Ceramics and Composites: A: Ceramic Engineering and Science Proceedings, Volume 24, Issue 3

27th Annual Cocoa Beach Conference on Advanced Ceramics and Composites: A: Ceramic Engineering and Science Proceedings, Volume 24, Issue 3

How to Cite

Herzog, R., Majerus, P., Mönch, J., Steinbrech, R. W., Schubert, F. and Singheiser, L. (2008) Study of Crack Development in APS and EB-PVD TBCS with Bending Tests Using Acoustic Emission and In-Situ Visual Observation, in 27th Annual Cocoa Beach Conference on Advanced Ceramics and Composites: A: Ceramic Engineering and Science Proceedings, Volume 24, Issue 3 (eds W. M. Kriven and H.-T. Lin), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294802.ch69

Author Information

  1. Research Centre Jüulich, IWV 2, 52425 Jülich, Germany

Publication History

  1. Published Online: 27 MAR 2008
  2. Published Print: 1 JAN 2003

ISBN Information

Print ISBN: 9780470375839

Online ISBN: 9780470294802

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Keywords:

  • oxide compounds;
  • thermal barrier coating;
  • electron-beam physical vapor deposition;
  • thermal expansion;
  • partially yttria stabilized zirconia

Summary

3-point and 4-point bending tests have been performed on bar-type CMSX-4 specimens coated with a NiCoCrAlY bond coat and a thermal barrier coating applied by APS and EB-PVD respectively. The TBC has been deformed under tensile and compressive loading with constant deflection rate at room temperature and at 950°C. The development of segmentation and delamination cracks has been observed in-situ using a CCD camera with telescope optic and by monitoring acoustic emissions. The increase of acoustic events was used to determine the initiation of segmentation and delamination cracks. Tests have been performed with as-coated specimens and after annealing for 300 h at 1050°C. The initiation of segmentation and delamination cracks was found to be affected by the deflection rate for both coating types. Thus, increasing the deflection rate reduced the respective strain value. The annealing treatment led further to a decrease of strain values for cracking within the ceramic top coat.