Temperature effects on fatigue thresholds and structure sensitive crack growth in a nickel-base superalloy

M.A. Hicks, J.E. King

    Research output: Contribution to journalArticle

    Abstract

    Fatigue thresholds and slow crack growth rates have been measured in a powder formed nickel-base superalloy from room temperature to 600°C. Two grain sizes were investigated: 5-12 μm and 50 μm. It is shown that the threshold increases with grain size, and the difference is most pronounced at room temperature. Although crack growth rates increase with temperature in both microstructures, the threshold is only temperature dependent in the material with the larger grain size. It is also only in the latter that the room temperature threshold falls when the load ratio is increased from 0.1 to 0.5. At 600°C the higher load ratio causes a 20% reduction in the threshold irrespective of grain size. The results are discussed in terms of surface roughness and oxide-induced crack closure, the former being critically related to the type of crystallographic crack growth, which is in turn shown to be both temperature and stress intensity dependent. © 1983.

    Original languageEnglish
    Pages (from-to)67-74
    Number of pages8
    JournalInternational Journal of Fatigue
    Volume5
    Issue number2
    DOIs
    Publication statusPublished - Apr 1983

    Keywords

    • crack closure
    • fatigue
    • fatigue crack growth
    • fatigue thresholds
    • grain size
    • nickel-base superalloys
    • temperature effects

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