You are being redirected because this document is part of your ASTM Compass® subscription.
    This document is part of your ASTM Compass® subscription.

    If you are an ASTM Compass Subscriber and this document is part of your subscription, you can access it for free at ASTM Compass
    STP945

    The Effect of Loading History on Closure Behavior in Rene' 95

    Published: 01 January 1988


      Format Pages Price  
    PDF (248K) 14 $25   ADD TO CART
    Complete Source PDF (20M) 1091 $132   ADD TO CART

    Cite this document

    X Add email address send
    X
      .RIS For RefWorks, EndNote, ProCite, Reference Manager, Zoteo, and many others.   .DOCX For Microsoft Word


    Abstract

    Experimental observations of closure in fatigue crack growth as a function of loading history are presented for a high-strength nickel-base superalloy, Rene' 95, at 649°C. Fatigue crack propagation (FCP) tests were conducted under either constant load amplitude (increasing ΔK) or under threshold load shedding (decreasing ΔK) test conditions. Closure loads were determined from load-offset displacement traces that were recorded with the aid of a crack mouth opening displacement extensometer. Plots of Kcl versus Kmax revealed that Kcl remained constant for both the constant load and decreasing load FCG tests, indicating that Kcl was not a consequence of the loading history. Similar plots for side-grooved specimens and smooth specimens revealed identical behavior, thus ruling out plasticity-induced closure as the operating closure mechanism.

    Keywords:

    crack closure, crack growth mechanisms, elevated temperature, nickel-base superalloy, fatigue crack propagation, fracture mechanics, oxidation, threshold


    Author Information:

    Zawada, LP
    Materials engineer and senior scientist, AFWAL/MLLN, Wright-Patterson Air Force Base, OH

    Nicholas, T
    Materials engineer and senior scientist, AFWAL/MLLN, Wright-Patterson Air Force Base, OH


    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP23242S