Chapter 2. A Multiaxial Viscoplastic Model for Advanced Si3N4 Ceramics

  1. John B. Wachtman Jr.
  1. J. L. Ding1,
  2. K. C. Liu2 and
  3. C. R. Brinkman2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470314821.ch2

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

Ding, J. L., Liu, K. C. and Brinkman, C. R. (1996) A Multiaxial Viscoplastic Model for Advanced Si3N4 Ceramics, 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.ch2

Author Information

  1. 1

    Washington State University, Pullman, WA 99164

  2. 2

    Oak Ridge National Laboratory, 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:

  • plasticity;
  • sensitivity;
  • multiaxial;
  • generalization;
  • microstructural

Summary

A uniaxial creep/creep rupture model developed previously based on results obtained from uniaxial tensile creep tests of an advanced Si3N4 ceramic has been refined and upgraded in multiaxial form to facilitate general applications. Severity of asymmetric creep behavior in tension compared to that in compression observed in recent experimental results mandates this revision. The tonsorial formulation follows the plasticity theories developed for soils. Material sensitivity to pressure, asymmetry between tension and compression, changes of material structure due to hardening of grain boundary phase, and deformation induced volumetric swelling attributable to cavity and void formations have all been considered. Provisions for such features in the proposed multiaxial model are shown to have improved modeling flexibility.