Chapter 31. Indentation Fracture Assessment of Residual Stress in Si3N4
- John B. Wachtman Jr.
Published Online: 26 MAR 2008
Copyright © 1996 The American Ceramic Society
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
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1996
Print ISBN: 9780470375426
Online ISBN: 9780470314821
- electron microscopes;
- geometric constant;
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.