STP725

    A Microstructural Explanation for the Low Swelling of Ferritic Steels

    Published: Jan 1981


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    Abstract

    It is proposed that the low swelling in ferritic steels occurs primarily because two kinds of interstitial loops can form in such body-centered cubic (bcc) steels: the so-called cube edge loops with <100> Burgers vectors lying on {100} planes and the usual glissile edge loops with the smaller <111> Burgers vectors lying on {111} planes. The crystallographic mode of formation of these loops from a common faulted loop nucleus on a {110} plane has been investigated previously by both computer simulation and by analytic methods, and there is direct transmission electron microscopy evidence for the simultaneous existence of the two loop types. In the present paper we summarize the salient features of this microstructural evidence with particular reference to neutron-irradiated material. An analysis to estimate the probability of forming the cube edge loop is presented and indicates the rather special aspects of iron compared with other bcc metals. The effect of the presence of such cube loops on the evolvement of the microstructure during irradiation is discussed. It is concluded that the simultaneous creation of these two sink types can be sufficient to inhibit greatly the formation and growth of voids and can also explain many of the observed microstructural features in ferritic steels after high-dose fast neutron irradiation.

    Keywords:

    swelling (materials), ferritic steels, microstructure


    Author Information:

    Bullough, R
    Group leader and staff scientist, Theoretical Physics Division and staff scientist, Metallurgy Division, A.E.R.E. Harwell, Oxfordshire,

    Wood, MH
    Group leader and staff scientist, Theoretical Physics Division and staff scientist, Metallurgy Division, A.E.R.E. Harwell, Oxfordshire,

    Little, EA
    Group leader and staff scientist, Theoretical Physics Division and staff scientist, Metallurgy Division, A.E.R.E. Harwell, Oxfordshire,


    Paper ID: STP28238S

    Committee/Subcommittee: E10.02

    DOI: 10.1520/STP28238S


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