SEDL / STP / STP1256-EB / STP16400S

Evaluation and Significance of Fracture Toughness in Ceramic Materials

Mutoh, Y
Professor, Nagaoka University of Technology, Nagaoka-shi,

Pages: 14    Published: Jan 1995

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Abstract

Fracture toughness tests of several ceramic materials were carried out according to the various test methods, that is the Bridge indentation(BI, SEPB), Fatigue precrack(FP), Controlled surface flaw(CSF), Chevron notch(CN) and Indentation fracture(IF) methods. Mutual comparison of the test results was made to discuss the validity and applicability of the each test method. Significance of the apparent fracture toughness with stable crack growth was discussed. The intrinsic fracture toughness can be obtained by the CSF method, in which a small surface crack is used. At high temperatures, since nonlinear deformation due to softening of glass phase and stable crack growth occur, nonlinear fracture mechanics approach should be applied. J^IC-value is successfully evaluated according to the R-curve method.