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Failure Prediction of the Thermal Fatigue of Silicon Nitride
Author(s) -
HASSELMAN D. P. H.,
CHEN E. P.,
AMMANN C. L.,
DOHERTY J. E.,
NESSLER C. G.
Publication year - 1975
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.1151-2916.1975.tb18771.x
Subject(s) - materials science , silicon nitride , brittleness , catastrophic failure , thermal , thermal fatigue , silicon , grain boundary , nitride , composite material , fracture mechanics , turbine , fracture (geology) , structural engineering , forensic engineering , metallurgy , mechanical engineering , microstructure , engineering , thermodynamics , layer (electronics) , physics
Slow crack growth data were used to predict the thermal fatigue life of silicon nitride parts subjected to the cyclic thermal environment of a turbine engine. For this purpose, a computer program was devised which numerically calculates the extent of slow crack growth for each successive thermal cycle until catastrophic failure occurs. Reasonable agreement was found between predicted and experimental fatigue life. Discrepancies were attributed to uncertainties in the values for the property data required for the fatigue calculations, as well as to statistical aspects of brittle fracture. Results of failure predictions for materials having flaw depths smaller than those encountered in the present specimens suggest that silicon nitride can be made more resistant to thermal fatigue by minimizing the amount of viscous grain‐boundary phase, which is responsible for slow crack growth.