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Quantitative Analysis of Crack Shielding Degradation During Cyclic Fatigue of Alumina
Author(s) -
Attaoui Hassan El,
Saâdaoui Malika,
Chevalier Jérôme,
Fantozzi Gilbert
Publication year - 2005
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.1551-2916.2004.00037.x
Subject(s) - materials science , cyclic stress , grain size , composite material , degradation (telecommunications) , electromagnetic shielding , bridging (networking) , ceramic , computer network , telecommunications , computer science
Grain bridging degradation behind a crack tip is the main cyclic fatigue mechanism in nontransforming ceramics. In this work, a compliance function is used to quantify the shielding capacity of grain bridges during cyclic loading of alumina ceramics with different grain sizes. This allows to identify the different stages occurring during cyclic loading. Significant degradation is observed in the coarse grain material and a marked sensitivity to the loading level is outlined. At moderate loads, bridging degradation occurs prior to fatigue crack growth during an incubation period which can reach several million cycles. At low cyclic loads, the shielding capacity can be entirely degraded, leading to a cyclic fatigue threshold equivalent to that of the fine grain material.