Chapter 56. Exclusivity of Strength-Limiting Extrinsic Surface and Hybrid Flaws

  1. Rajan Tandon,
  2. Andrew Wereszczak and
  3. Edgar Lara-Curzio
  1. A. A. Wereszczak and
  2. T. P. Kirkland

Published Online: 27 MAR 2008

DOI: 10.1002/9780470291313.ch56

Mechanical Properties and Performance of Engineering Ceramics II: Ceramic Engineering and Science Proceedings, Volume 27, Issue 2

Mechanical Properties and Performance of Engineering Ceramics II: Ceramic Engineering and Science Proceedings, Volume 27, Issue 2

How to Cite

Wereszczak, A. A. and Kirkland, T. P. (2006) Exclusivity of Strength-Limiting Extrinsic Surface and Hybrid Flaws, in Mechanical Properties and Performance of Engineering Ceramics II: Ceramic Engineering and Science Proceedings, Volume 27, Issue 2 (eds R. Tandon, A. Wereszczak and E. Lara-Curzio), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291313.ch56

Author Information

  1. Ceramic Science and Technology Group Metals and Ceramics Division Oak Ridge National Laboratory Oak Ridge, TN 37831–6068

Publication History

  1. Published Online: 27 MAR 2008
  2. Published Print: 1 JAN 2006

ISBN Information

Print ISBN: 9780470080528

Online ISBN: 9780470291313

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Keywords:

  • extrinsic;
  • homogenously;
  • fractography;
  • hexoloy;
  • elliptical

Summary

Flexure strength–limiting flaw populations were examined in a sintered alpha–SiC having ∼6 vol% porosity comprised of homogenously distributed monosized (∼60–70 μm) pores. Bend bars were coarse–, medium–, and fine–finish ground with the intent to produce concurrent activity of intrinsic strength–limiting flaws (pores) and extrinsic strength–limiting flaws (machining damage) populations. However, this was not achieved as fractography showed that strength was always limited by a pore independent of the depth of machining damage in this material. The effects of strength–limiting flaw hybridization on 2–Parameter Weibull were then examined by positioning Knoop indents either directly on a pore present at the ground surface of the bend bars or away from them, and flexure loading those specimens to fracture. Fractography confirmed the suggestion in this case that a negative curvature in the Weibull distribution curve was associated with exclusive strength–limiting flaw populations (hybrid and surface flaw types). The interpretation of intrinsic and extrinsic exclusive flaw distributions is discussed in reference to the prospective selection of a ceramic for structural applications.

IV.SUMMARY