Chapter 31. Indentation Fracture Assessment of Residual Stress in Si3N4

  1. John B. Wachtman Jr.
  1. K. H. Wu1,
  2. Ken C. Liu2 and
  3. M. Sentella2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470314821.ch31

Proceedings of the 20th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 17, Issue 3

Proceedings of the 20th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 17, Issue 3

How to Cite

Wu, K. H., Liu, K. C. and Sentella, M. (2008) Indentation Fracture Assessment of Residual Stress in Si3N4, in Proceedings of the 20th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 17, Issue 3 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314821.ch31

Author Information

  1. 1

    Florida International University, Miami, FL 33199

  2. 2

    Oak Ridge National Laboratory, Metals and Ceramics Divisions, Oak Ridge, TN 37831

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1996

ISBN Information

Print ISBN: 9780470375426

Online ISBN: 9780470314821

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Keywords:

  • electron microscopes;
  • geometric constant;
  • optimize;
  • indentation;
  • superimposition

Summary

The measurement of residual stress in Si3N4 ceramics was examined using the indentation technique while a bar specimen with a square cross-section was loaded in tension, and an indentation was created by means of a Vicker's indenter. The stress applied to the specimen ranged from 0 to 98.8 MPa. The crack length and the shape of the crack were measured by both optical and scanning electron microscopes. Results of the tests indicate that the indentation fracture method can be used to accurately determine the residual stress existing in the material as well as to predict the Kc value of the material. The indentation load must be higher than a critical value in order to develop a well-defined penny-shaped crack. For the Si3N4 this critical load is approximately 3 kg. A geometric constant is an important factor for the calculation of the residual stress.