Dislocation-mediated strain hardening in tungsten: Thermo-mechanical plasticity theory and experimental validation

    Research outputpeer-review

    Abstract

    A self-consistentthermo-mechanicalmodeltostudythestrain-hardeningbehaviorof polycrystallinetungstenwasdevelopedandvalidatedbyadedicatedexperimentalroute. Dislocation–dislocationmultiplicationandstorage,aswelldislocation-grainboundary (GB)pinningwerethemajormechanismsunderlyingtheevolutionofplasticdeformation, thus providingalinkbetweenthestrainhardeningbehaviorandmaterial'smicro- structure.Themicrostructureofthepolycrystallinetungstensampleshasbeenthoroughly investigatedbyscanningandelectronmicroscopy.Themodelwasappliedtocompute stress–strain loadingcurvesofcommercialtungstengrades,intheas-receivedandas- annealedstates,inthetemperaturerangeof500–1000 °C. Fittingthemodeltothein- dependentexperimentalresultsobtainedusingasinglecrystalandas-receivedpoly-crystalline tungsten,themodeldemonstrateditscapabilitytopredictthedeformation behavior ofas-annealedsamplesinawidetemperaturerangeandappliedstrain.The relevanceofthedislocation-mediatedplasticitymechanismsusedinthemodelhavebeen validatedusingtransmissionelectronmicroscopyexaminationofthesamplesdeformed up todifferentamountsofstrain.Onthebasisoftheexperimentalvalidation,thelim- itationsofthemodelaredeterminedanddiscussed.
    Original languageEnglish
    Pages (from-to)1-15
    Number of pages15
    JournalJournal of the Mechanics and Physics of Solids
    Volume85
    DOIs
    StatePublished - 28 Aug 2015

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