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

    Scatter in Fatigue Crack Growth Rate in a Directionally Solidified Nickel-Base Superalloy

    Published: 01 January 2004

      Format Pages Price  
    PDF (300K) 12 $25   ADD TO CART
    Complete Source PDF (6.4M) 276 $87   ADD TO CART

    Cite this document

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


    Directional solidification of nickel-base superalloy components for gas turbine rotor blades offers a significant improvement in creep strength while at the same time yielding an anisotropic, heterogeneous microstructure. In such a material, some of the continuum assumptions of linear elastic fracture mechanics begin to break down, and local (microscopic) conditions can lead to significant deviation in fatigue crack growth rate from the global (macroscopic) trend. Fatigue crack life prediction for a large population of fielded components requires a probabilistic treatment of the material fatigue crack growth behavior. A common approach to probabilistic fatigue crack life prediction involves sampling the Paris law coefficients from a large number of crack growth experiments, which can lead to effectively “smoothing” the local intraspecimen variability out of the model. The length scale of variability is discussed as it relates to material microstructure and crack life prediction. Results from fatigue crack growth experiments on a directionally solidified superalloy are presented and spatial variation in the fatigue crack growth rate is examined. Periodicity of the crack growth rate variation is compared with the scale of microstructural heterogeneity.


    probabilistic fracture mechanics, crack growth, directionally solidified, nickel-base superalloy, microstructure

    Author Information:

    Highsmith, S
    Graduate Research Assistant, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA

    Johnson, WS
    Professor, School of Materials Science and George P. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP11282S