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Characterizing Brittle Fracture by Modeling Crack Deflection Angles from the Microstructure
Author(s) -
Porz Lukas,
Wei Sai,
Zhao Jiamin,
Patterson Eric A.,
Liu Bin
Publication year - 2015
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/jace.13822
Subject(s) - materials science , fracture toughness , crack growth resistance curve , fracture mechanics , microstructure , deflection (physics) , composite material , residual stress , brittleness , grain boundary , toughness , crack closure , optics , physics
This study introduces a simple analytical model for fracture toughness to bridge the length scales from grain size to bulk thickness by assembling a virtual crack path from the angles recorded on an unfractured microstructure, which is a great challenge in fracture mechanics due to the high geometrical complexity. Good agreement is found between a crack deflection angle distribution measured from 5764 crack segments and the prediction by the model and the possible influence of residual stress is quasi quantitatively discussed. A total of 7.4% of the crack segments observed acted as crack bridges, while 7.3% was predicted by the model. A quantification of how high an angle needs to be to turn crack deflection into crack bridging is given. The ratio of fracture toughness from grain boundary to grain, G 1c(gb) / G 1c(g) , was measured indirectly from all samples to be between 0.3 and 0.35.