Cyclic fatigue in ceramics: A balance between crack shielding accumulation and degradation

Journal Article · Wed Mar 01 04:00:00 EST 1995 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1995.tb08208.x· OSTI ID:79760

Jacobs, D S; Chen, I W ^[1]

---

1. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering

Cyclic fatigue growth rates in R-curve ceramics have been observed to depend very strongly on the maximum applied stress intensity, K{sub max}, and only weakly on the stress intensity range, {Delta}K. This behavior is rationalized through measurement of crack wake shielding characteristics as a function of these fatigue parameters in a gas-pressure-sintered silicon nitride. In particular, evidence for a mechanical equilibrium between shielding accumulation by crack growth and shielding degradation by frictional wear of sliding interfaces is found for steady-state cyclic fatigue. This equilibrium gives rise to a rate law for cyclic fatigue. The data suggest that the accumulation process is the origin of the strong K{sub max} dependence, and that the degradation process is the origin of the weak {Delta}K dependence. These features are shown to be related to the ``cyclic`` R-curve and to the cyclic crack opening displacement, respectively.

• Sponsoring Organization: USDOE
• OSTI ID: 79760
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 3 Vol. 78; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRACK PROPAGATION
CRACKS
DAMAGE
FATIGUE
FRACTURE MECHANICS
INTERFACES
MATHEMATICAL MODELS
SILICON NITRIDES
SLIDING FRICTION
STRESS INTENSITY FACTORS