STP1389

    Dislocation Mechanics Basis and Stress State Dependency of the Master Curve

    Published: Jan 2000


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    Abstract

    The Master Curve approach to characterizing fracture toughness transition behavior of pressure vessel steels is based on statistical analysis of empirical data and not on a physics-based understanding of the fracture behavior of these steels. While there is an over-abundance of empirical data that supports the idea of a single curve shape for all pressure vessel steels, this cannot replace the need for solid physical modeling. The lack of fracture toughness data for a considerable proportion of the nuclear fleet suggests that a purely empirical argument cannot validate the Master Curve for all conditions of interest. In order to validate the Master Curve approach research has been undertaken to provide a physical understanding of the fracture behavior of pressure vessel steels. This will provide the basis for defining the limits of the Master Curve as well as for enabling extrapolation of the Master Curve model to other material conditions with only limited testing. A previous paper [1] detailed a dislocation mechanics-based constitutive model approach to describe the link between microstructure and temperature dependence of flow and fracture toughness behavior. In this paper, the strain to fracture under the appropriate stress state will be discussed in terms of the dislocation mechanics-based constitutive models and the effect on the shape of the Master Curve.

    Keywords:

    master curve, fracture toughness transition behavior, T0, steel


    Author Information:

    Natishan, ME
    Assistant professor and graduate student, University of Maryland, College Park, MD

    Wagenhofer, M
    Assistant professor and graduate student, University of Maryland, College Park, MD

    Kirk, MT
    Senior mechanical engineer, Westinghouse Electric Company, Pittsburgh, PA


    Paper ID: STP14807S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP14807S


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