SEDL / STP / STP745-EB / STP28302S

The Character of Cracks In Fracture Toughness Measurements of Ceramics

Wu, CC
Research ceramic engineer and head, Ceramics Branch, Naval Research Laboratory, Washington, D.C.,

Rice, RW
Research ceramic engineer and head, Ceramics Branch, Naval Research Laboratory, Washington, D.C.,

Becher, PF
research staff member, Oak Ridge National Laboratory, Oak Ridge, Tenn.

Pages: 14    Published: Jan 1981

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Abstract

X-ray microradiographic and in situ SEM techniques that are complimentary and uniquely suitable for characterizing cracks and crack propagation in brittle materials are described. Results obtained from these observations in ceramics show that the cracks are not generally of the ideal character assumed in the typical fracture mechanics analysis. Local microstructure as well as the crystallographic structure of the specimens are shown to be important in determining crack variations. These results are discussed in terms of evaluating and improving the fracture toughness measurements.