A Comparison of the Electron and Ion Irradiation Effects on the在电子和离子束辐照效应的比较

ACOMPARISONOFTHEELECTRONANDIONIRRADIATIONEFFECTSONTHESTABILITYRANGEOFORDEREDSTRUCTURESINNi4Mo

M.SUNDARARAMAN*andS.BANERJEEPresentedby

G.K.DEYMaterialsScienceDivisionBhabhaAtomicResearchDivisionMumbai400085*OutlineOrdering–chemical,magnetic,&electricEvolutionofOrderingCompetingsuperlatticesinNi4MoalloyInfluenceofradiationonorderdisorderOrderevolution--underelectronirradiation--underheavyionirradiationComparisonofelectronandionirradiationresultsConclusionsOrdering

–Chemical,ferromagnetic,ferroelectric

ChemicalOrderingFerromagneticFerroelectricOrderingEmptylatticeAtomsA&BElectric/magneticmomentsOutlineOrdering–chemical,magnetic,&electric

EvolutionofOrderingCompetingsuperlatticesinNi4MoalloyInfluenceofradiationonorderdisorderOrderevolution--underelectronirradiation--underheavyionirradiationComparisonofelectronandionirradiationresultsConclusionsEvolutionoforderNucleationandGrowthContinuousOrderingOrderevolutioncouldbeeitherfirstorsecondorderEvolutionofOrdering:DiscreteMode(Nucleation&Growth)NucleationDisorderedMatrixEvolutionofOrdering–StaticConcentrationWavesSingleVariant<100>Kvector–B2Ordering3variants<100>Kvector–L12orderingContinuousOrderingAmplificationofconcentrationwavewithtimeFirst&secondordertransitions:Thermodynamicviewpointnthordertransformation:FECpTemperature

FirstOrderSecondorderEnergybarrierNucleation&growthFirst&secondordertransitions:LandauPlotsFirstOrder(Discrete)Secondorder(Continuous)OutlineOrdering–chemical,magnetic,&electricEvolutionofOrdering

CompetingsuperlatticesinNi4Moalloy

InfluenceofradiationonorderdisorderOrderevolution--underelectronirradiation--underheavyionirradiationComparisonofelectronandionirradiationresultsConclusionsOrderedStatesinNi4Mo*Above1140KalloyisinSROstate*Below1140KalloyisinLROstate*Byconventionalsolutionisingandquenchingtreatmentalloycannotbeproducedinthecompletelydisorderedstate(CDO)*LROandSROaretwodifferentstatesDescriptionofLROandSROstructures[001]ProjectionLROstateSROstatep=0,1,2,3for<1½0>modulationp=0,1,2,3,4for1/5<1½0>modulationConcentrationwavepacketsMicrodomainsStructuraldescriptionof<1½0>OrderingIsostructuralmicrodomainsSRO<1½0>

LRO1/5<420>DifferentfromSROintensifyingtobecomeLROMultiplemicrodomainsDisorderedmatrixOutlineOrdering–chemical,magnetic,&electricEvolutionofOrderingCompetingsuperlatticesinNi4Moalloy

Influenceofradiationonorderdisorder

Orderevolution--underelectronirradiation--underheavyionirradiationComparisonofelectronandionirradiationresultsConclusionsOutlineOrdering–chemical,magnetic,&electricEvolutionofOrderingCompetingsuperlatticesinNi4MoalloyInfluenceofradiationonorderdisorder

Orderevolution

--underelectronirradiation--underheavyionirradiationComparisonofelectronandionirradiationresultsConclusionsElectronIrradiationResults1MeVelectronsDoserate=10-3dpa/sEvolutionofOrderinNi4MounderelectronIrradiation170K473KDisorderingofLROstatePersistenceof1½0order(SRO)ininitialSROstateEvolutionofOrderinNi4MounderelectronIrradiationDamagerate:10—3dpa/s<1½0>&1/5<420>diffractionspotsremainlinkedduringevolutionarystagesSBanerjee,KUrban,M.WilkensActaMet.,32(1984)299OrderingMechanismsMapsforNi4Moundere-irradiationA:DestructionofLROB:NosignificantchangeoforderforS=0,S=1C:Continuousorderingbydecayof<1½0>waves&simultaneousamplificationofLROD:InitiallyasinregionC,after<1½0>disappear,D1adomainsnucleate&growE:Nucleation&growthofD1aF:Destructionof<1½0>G:<1½0>orderdecaysatT>550KH:<1½0>growsI:Destructionof<1½0>&transitiontoLROSBanerjee,KUrban,M.WilkensActaMet.,32(1984)299NoLROstatebelow450KNoSROStatebelow200KOrdering&DisorderingJumpsAsymmetricenergybarrierforvacancy-atomInterchangeinorderedalloyOrder-parametervs.temperatureplotsequilibriumcondition-steadystateconditionunderirradiationComparisonbetweentheory&experimentequilibriumUnderirradiationS.Banerjee,K.Urban,Phys.Stat.Sol.,81,(1984)145OutlineOrdering–chemical,magnetic,&electricEvolutionofOrderingCompetingsuperlatticesinNi4MoalloyInfluenceofradiationonorderdisorder

Orderevolution--underelectronirradiation

--underheavyionirradiationComparisonofelectronandionirradiationresultsConclusionsIonIrradiationResults300keVNi+ionsDoserate=10-3dpa/sDisplacementcascadesproducedby60keVAu++ionsinorderedNi4Mo(D1a)Black-whitecontrastFromDislocationloops(g=200)DisorderedzonesimageswithSuperlatticereflection(g=1/5<420>M.Sundararaman,S.Banerjee,H.Wollenberger,ActaMet.,43,(1995)107EvolutionofOrderinNi4MounderionIrradiationGradualdecayofSROandLROstatestoCDOstateEvolutionofOrderinNi4MounderionIrradiationDecayofLROandgradualdevelopmentofSROintensity300keVNi+;Irradiationtemperature-600KDoserate-10-3dpa/sEvolutionofOrderinNi4MounderionIrradiationDevelopmentofSROintheinitiallySROandLROspecimensi-SROi-LROEvolutionoforderinNi4MounderionIrradiationFinalsteadystatesatdifferentirradiationtemperaturesi-SROi-LROLoopsizegreaterthan10nmDislocationloopsinirradiatedNi4Mo;T=900CFrankloopsSteadystatestructuresinNi4MounderionirradiationInitialstateDomainsTransitions

<1½0>A<1½0>disappearsB<1½0>decaysC<1½0>growsDexperimentallyinaccessible

1/5<420>E1/5<420>decays&<1½0>growsF1/5<420>persistsCascadedynamicsDisplacementcascade–10-13sThermalspike–10-11sFinalorderdecidedbydisorderingandreorderingwithinthermalspikeQuenchingofthermalspike

-Amorphous -Completedisorder -PartialOrderNetvacancyconcentrationinsidethecascadeBydiffusiontoperipheryformloopsaroundcascadeSubstrate/sampletemperature/thermalconductivityComparisonofelectronandionirradiationresultsComparisonbetweenelectron&ionirradiationSteadystatestructuresdevelopedduringe-andionirradiationStochasticpotentialformaximumorderversusTExperimentTheoryLowerboundforLROstabilitymatcheswithexperimentfore-irradiationConclusionsDistinctstabilityregimesfortheCDO,theSROandtheLROstatescouldbeobtainedforelectronandionirradiationCascadeeffectdecreasesthetemperaturerangeofstabilityofLROstatewhileincreasesthetemperaturerangeofstabilityofSROstateForelectronirradiation,mixedstate(SROandLRO)canco-existbetween450Kand800K.NomixedstateexistforionirradiationLowtemperatureforstabilityofLROcalculatedbyKineticandstochasticmodelsmatchwithexperimentalobservationforelectronirradiationAcknowledgmentsDr.U.D.Kulkarni,BARCProf.K.Urban,KFA,JülichProf.H.Wollenberger,HMI,BerlinThankyouReactionkineticsmodelKinetics:RateofChangeofpoint-defectconcentrations

(Vacancy,V,&Interstitial,I)

ProductiontransfertransferAnnihilationatsinksRecombination,:sublatticesitesS.Banerjee,K.Urban,Phys.Stat.Sol.,81,(1984)145RadiationEffectsinSolidsRadiationEnhanced/InducedSegregationRadiationEnhanced/InducedDiffusionRadiationEnhanced/InducedPhaseTransformation

-Generationofnewphases-vacancyorderedRadiationEnhanced/InducedRedistributionIrradiationinducedprocessesDisordering–temperatureindependentReordering-temperaturedependentNeteffectdecidesthefinalstructureRa