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Toughening of a Particulate‐Reinforced Ceramic‐Matrix Composite by Thermal Residual Stress
Author(s) -
Taya Minoru,
Hayashi S.,
Kobayashi Albert S.,
Yoon H. S.
Publication year - 1990
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1990.tb05209.x
Subject(s) - materials science , composite material , composite number , particulates , micromechanics , residual stress , thermal expansion , ceramic , ultimate tensile strength , volume fraction , fractography , ecology , biology
The micromechanics involved in increased crack growth resistance, K R , due to the addition of TiB 2 particulate in a SiC matrix was analyzed both experimentally and theoretically. The fractography evidence, in which, the advancing crack was attracted to adjacent particulates, was attributed to the tensile region surrounding a particulate. Countering this effect is the compressive thermal residual stress, which results in the toughening of the composite, in the matrix. This thermal residual stress field in a particulate‐reinforced ceramic‐matrix composite is induced by the mismatch in the coefficients of thermal expansion of the matrix and the particulate when the composite is cooled from the processing to room temperature. The increase in K R of the composite over the monolithic matrix, which was measured by using a hybrid experimental‐numerical analysis, was 77%, and compared well with the analytically predicted increase of 52%. The increase in K R predicted by the crack deflection model was 14%. Dependence of K R on the volume fraction of particulates, f p , and of voids, f v , is also discussed.