STP1125

    Interfacial Segregation in Fast Reactor Irradiated 12% Chromium Martensitic Steel

    Published: Jan 1992


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    Abstract

    Interfacial solute segregation has been studied in FV448-grade 12% chromium martensitic stainless steel following fast reactor irradiation to damage levels of 25 and 46 dpa at temperatures of 400 and 465°C, respectively. The technique of field emission gun scanning transmission electron microscopy has been used to measure solute redistribution profiles, with high spatial resolution, across martensite lath boundaries. Significant nickel and silicon enrichments are detected at the lath boundaries. Chromium levels exhibit more complex behavior, with localized enrichment at the boundary itself but depletion in adjacent matrix regions. These radiation-induced segregation eifects imply that martensite lath boundaries act as major point-defect sinks during neutron irradiation. The magnitude of the silicon segregation is greatest at 400°C, whereas nickel and chromiun concentrations are relatively temperature insensitive. The data are broadly consistent with the current understanding of nonequilibrium segregation processes based on solute atom size effects.

    Keywords:

    ferritic-martensitic stainless steel, fast reactor irradiation, radiation-induced segregation, field emission gun scanning transmission electron microscope (FEGSTEM), lath boundaries


    Author Information:

    Morgan, TS
    Research student and reader, Institute of Polymer Technology and Materials Engineering. University of Technology, Loughborough, Leicestershire

    Little, EA
    Senior scientist, Materials and Chemistry Division, Harwell Laboratory, Didcot, Oxfordshire

    Faulkner, RG
    Research student and reader, Institute of Polymer Technology and Materials Engineering. University of Technology, Loughborough, Leicestershire

    Titchmarsh, JM
    Senior scientist, Materials and Chemistry Division, Harwell Laboratory, Didcot, Oxfordshire


    Paper ID: STP17900S

    Committee/Subcommittee: E10.08

    DOI: 10.1520/STP17900S


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