Effect of inclusion on subsurface crack initiation and gigacycle fatigue strength

Q. Y. Wang, C. Bathias, N. Kawagoishi, Q. Chen

Research output: Contribution to journalArticlepeer-review

387 Citations (Scopus)


The effect of inclusions on crack initiation and propagation in gigacycle fatigue was investigated experimentally and analytically in six high strength low alloy steels. Fatigue testing was performed at very high numbers of cycles through ultrasonic fatigue tests at 20 kHz. Inclusions at subsurface are common sites for fatigue crack nucleation in these alloys when cycles to failure was > 107 cycles. A significant change in the slope of the S-N curve was observed accompanying the transition from surface to subsurface crack initiation. A deterministic model has been developed to predict the total fatigue life, i.e. crack initiation life and crack propagation life, from the measured inclusion sizes. The predicted fatigue strength agreed reasonably well with the experimental results. It is a tendency that smaller inclusions are associated with longer fatigue life. The results demonstrated that the portions of life attributed to subsurface crack initiation between 107 and 109 cycles are > 99%.

Original languageEnglish
Pages (from-to)1269-1274
Number of pages6
JournalInternational Journal of Fatigue
Issue number12
Publication statusPublished - Dec 2002
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Modelling and Simulation
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering


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