Chapter 41. In-Situ Observation of Crack Growth in Glassy Alumina at 1275°C
- John B. Wachtman Jr.
Published Online: 26 MAR 2008
Copyright © 1992 The American Ceramics Society
Proceedings of the 16th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 13, Issue 9/10
How to Cite
Heinzelmann, M., Ritter, J. E. and Jakus, K. (1994) In-Situ Observation of Crack Growth in Glassy Alumina at 1275°C, in Proceedings of the 16th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 13, Issue 9/10 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470313978.ch41
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1994
Print ISBN: 9780470375198
Online ISBN: 9780470313978
Crack propagation in a 85% alumina was studied in-situ at 1275°C as a function of displacement rates from 3 to 50 μm/min using short double cantilever beam (s-DCB) specimens with and without a rear-notch wedge. With the rear notch wedge the crack propagated by a creep rupture process that involved the nucleation of microcracks ahead of the main crack tip and the subsequent linkage of these microcracks to the main crack. This creep crack process produced a very tortuous crack path. The linkage of these creep-nucleated microcracks to the main crack gave rise to significant statistical variability in the load-displacement curves. This creep crack growth behavior was found to be dependent on the C*-integral where crack velocity was proportional to C* by a power law function. Without the rear notch wedge, creep nucleated microcracking was considerably reduced and crack propagation became more coplanar.