Grain boundary oxidation and oxidation accelerated fatigue crack nucleation and propagation

Author / Creator

Liu, H. W. (Hao Wen), 1926-

Conferences

Conference on Life Prediction for High-Temperature Gas Turbine Materials (1985 : Syracuse, N.Y.)

Available as

Online

Physical

Summary

"Fatigue life at elevated temperatures is often shortened by oxidation. Grain boundary oxidation penetrates deeper than the surface oxidation. Therefore, grain boundary oxide penetration could be t...

"Fatigue life at elevated temperatures is often shortened by oxidation. Grain boundary oxidation penetrates deeper than the surface oxidation. Therefore, grain boundary oxide penetration could be the primary cause of accelerated fatigue crack nucleation and propagation, and the shortened fatigue life at elevated temperatures. Grain boundary oxidation kinetics was studied and its statistical scatter was analyzed by the Weibull's distribution function. The effects of grain boundary oxidation on shortened fatigue life was analyzed and discussed. A model of intermittent microruptures of the grain boundary oxide was proposed for the fatigue crack growth in the low frequency region. The proposed model is consistent with the observations that fatigue crack growth rate in the low frequency region with hold time at K sub max is inversely proportional to cyclic frequency and that crack growth is intergranular."--NTIS abstract.

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