简介:BondingofAl2O3tocuisperformeddirectlyusingTifoilattemperatureof1273K.Themicrostructureofthejointinterfaceisinuestigatedthroughscanningelectronmicroscope(SEM),electron.probemicroanalysis(EPMA)andX-raydiffraction(XRD).theeffectoftheinitialtifoilthicknessonthereactionlayerthicknessandthejointStrengthareinvestigated.
简介:ArapidlysolidifiedAl-2.5Ti-2.5Fe-2.5Cr(massfractionin%)alloywaspreparedbymeltspinning.Asquenchedandas-annealedmicrostructureswerestudiedbyX-raydiffractometry(XRD),transmissionelectronmicroscopy(TEM),high-resolutiontransmissionelectronmicroscopy(HREM)andenergydispersivespectrum(EDS)analysis.Themicrohardnessofthealloyatdifferentannealingtemperatureswasmeasured.TheresultsobtainedindicatethatthemicrohardnessoftherapidlysolidifiedAl-2.5Ti-2.5Fe-2.5Cralloydoesnotvarywithdifferentannealingtemperatures.Theas-quenchedmicrostructureofthealloyincludestwokindsofdispersedprimaryphases:Al3TiandAl13(Cr,Fe)2.Afterannealingat400℃for10h,thestablephaseAl13Fe4appearsinthemicrostructure.
简介:ThemixturemodelofAl85Y4Nd4Ni7alloyinwhichapartiallycrystallizedamorphousalloyisregardedasananocompositeofanAlnanoparticleandaremainingamorphousmatrixispresented.Itsevolutionintheprocessofcrystallizationhasbeeninvestigatedbydifferentialscanningcalorimetry(DSC),X-raydiffraction(XRD),andtransmissionelectronmicroscopy(TEM).Mainlyamorphousstructurewithα-Alnanocrystalsembeddedintheamorphousmatrixhasbeenrevealedbymeltspiningthealloy.Crystallizationisshowedtooccurinthreestages:(1)crystallizationofamorphousalloyandformationofAlNiY,AlNdNiandunknowncrystallinephases,(2)formationofAl3YandAl3Nd,and(3)formationofAl3Ni.
简介:1IntroductionTherareearthcobaltalloyshavethepotentialformakingthemagneticandmagnetoopticalmaterials.Sofar,therareearthcobaltalloyfilmsaresubstantiallyproducedbysputteringorvacuumplating.Ifsuchfilmsarepreparedbyelectrodepositioninstead,productionefficiencywouldbeimprovedandthecompositionofthealloycouldbecontrolled.Becausetheoxidationreductionpotentialsofrareearthelementsareverynegative,organicsolventsmaybeusedaselectrolyticmedia.ElectrodepositionofGdCoandSmCoinorganicsolutionshasbeenreporte...
简介:ThesubmicronpowdermixturesofTiC-TiN-WC-Mo-C-Nisinteredat1400℃orbelowinvacuumwerestudiedbyX-raydiffraction(XRD),scanningelectronmicroscopy(SEM)andtransmissionelectronmicroscopy(TEM)analyses.TheresultsshowedthatMo2Cformedat800℃orbelow.BothWCandMo2Cdisappearedat1200℃,andTiNdisappearedat1250℃.Inaddition,thevariationsoflatticeconstantsofthetitaniumcarbonitrideandnickelbinderphasewithsinteringtemperaturewereexperimentallyobtained,andthereasonwasanalyzed.
简介:StudyonGdAlDySystemMagneticRefrigerationMaterialsChangXiumin,YanJunlian(常秀敏)(闫俊联)BeijingGeneralResearchInstituteforNonferr...
简介:ThehydrogenstoragepropertiesofTi1.2Fe+xCa(x=1%,3%and5%inmassfraction)alloyswasinvestigated.ResultsshowthatthemodifiedalloyscanbeactivatedwithoutanythermaltreatmentatroomtemperatureduetotheadditionofCaandexcessTiinthealloys.HydrogenstoragepropertiesofthesemodifiedalloysvarywithCaamountandreactiontemperature.Inaddition,theinfluencemechanismoftheadditionofCaandexcessiveTiontheactivationbehaviorandhydrogenstoragecapacityofthealloyswasdiscussed.
简介:MicrostructureandtextureofTi-Nb-Sibasedalloys,preparedbywaterquenchingfromβ-phasefield,coldrollingandrecrystallizationheattreatmentfollowedbywaterquenching,wereinvestigatedintermsofopticalmicrostructureandanalysisofX-raypolefigureresult.Inas-quenchedsample,relativelyrandomdistributionofpolefigurewasdetectedwithoutshowingaspecifictexturecomponent.Inas-coldrolledsample,however,itisfoundwell-developedseveraltexturecomponentsconsistingofrotatedcube,α-fiberandγ-fibertexturecomponentswhicharefrequentlyobservedinbcc-structuredmetalsandalloyswerefound.Therefore,texturecomponentsdevelopedinthepresentalloysarecloselyrelatedtothedeformationofβ-phaseeventhoughsmallamountofα″phaseco-existinthemicrostructure.Inrecrystallizedsample,α-fibertexturecomponentisweaklydetectedwhiletheothertexturecomponents,rotatedcubeandγ-fibercomponents,appearstoberelativelyunchanged.Noadditionaltexturecomponentsweredetectedbesidesthosetexturecomponentsobservedinthecoldrolledsamples.
简介:Thecorrosionbehaviorandanti-corrosionmechanismoftheZn-Ni-Al2O3compositecoatingwereinvestigatedbySEM,EDSandXPS.TheresultsindicatethatthecorrosiontypeoftheZn-Ni-Al2O3coatingsinneutral5wt.%NaClsolutionisuniformcorrosion.ThepresenceofcompactanduniformlydispersednanoaluminaparticlessubstantiallyinhibitsthecorrosionofZn-Ni-Al2O3compositecoatings.Intheinitialcorrosionstage,thecorrosiveproductsofZn-NimatrixformacompactZnCl2·4Zn(OH)2layer.Withthedevelopmentofcorrosion,somenanoaluminaparticlesareembeddedandformaNienrichmentlayer.InNienrichmentlayer,NipresentsasNiandNiO.
简介:ThefrictionandwearbehaviorofFe-Alintermetallicsbasedcoatingproducedbyhighvelocityarcsprayingtechniqueunderdryslidingatroomtemperaturewereinvestigatedusingaball-on-disctribotester.Theeffectofslidingspeedonfrictioncoefficientandwearofthecoatingwasstudied.Thewornsurfaceofthecoatingwasanalyzedbyscanningelectronmicroscope(SEM)toexploreslidingfrictionandwearmechanism.Theresultsshowthatthevariationsoffrictioncoefficientcanbedividedintothreedistinctstepsduringthetrail.Boththefrictioncoefficientandthewearofthecoatingincreasewithincreasedslidingspeedduetoacceleratedcrackpropagationrateandlamellarstructurewithpoorductilityofthecoating.Thecoatingsurfaceissubjectedtoalternatelytensilestressandcompressionstressduringslidingwearprocess,andthepredominantwearmechanismofthecoatingsappearstobebrittlefractureanddelamination.
简介:ThestoredenergyandtheenergyreleaseduringSPD(superplasticdeformation)ofaZn-5Alalloywerestudied.Thealloyafterrollingprocessgainsmorestoredenergy,andtheas-rolledspecimencanobtainmaximumelongationandminimumflowstresswithouthotholdingtreatmentbeforeSPD.ExperimentalresultsshowthatstoredenergyreleaseprocessisalongwithSPDprocessandisalsoanimpetustoSPD.Theas-rolledZn-5Alalloyhas48J/molstoredenergywhichwasmeasuredwithDSC(differentialscanningcalorimeter)andconformswelltothecalculatedvalue.Theas-rolledZn-5AlalloyafterSPDwithanelongationof2500%releases112J/molstoredenergy.Analysisshowsthatthestrainrateisindirectratiototherateofstoredenergyrelease.
简介:Therulessuchasprocessparametersaffectingjointpropertiesandtheevolutionprincipleofweld'smicrostructurehavebeenresearchedbyadoptingdiffusionweldingprocesstoconnectSiCw/6061Alcomposite.ExperimentalresultsshowthatthereexistsacriticaltemperatureregionbetweensolidandliquidphaselineofSiCw/6061Alcomposite,andtheregionwillshrinkwiththeincreasingofweldingpressure.Whendiffusionweldingoccurredunderthecriticaltemperatureregion,weldingjointexhibitsbadpropertyofbonding,andthematrixandthereinforcementcan'tbondeffectively.Whendiffusionweldingoccurredinthecriticaltemperatureregion,thestrengthofweldingjointchangeswidelywiththevariationofweldingtemperature.Whenweldingtemperaturevariesin10℃,thestrengthofweldingjointwillchangeobviously.Onlywhenweldingtemperatureishigherthanthecriticaltemperatureregion,stablejointpropertiescanbeobtained.Simultaneouslythematrixandthereinforcementhasbetterinterfacialbondedindiffusionweldinginterface,andnoobviousinterfacereactionoccurred,andthusdiffusionweldingofSiCw/6061Alcompositecanbesuccessfullyrealized.