简介:Fe3AlandCr18-Ni8steelwerebondedinvacuumandaninterfacewasformedbetweenFe3AlandCr18-Ni8steel.Stressdistributionatthediffusion-bondedinterfacewasresearchedbynumericalsimulationandfiniteelementmethod(FEM).TheresultsindicatedthatthepeakstressappearedattheinterfacenearCr18-Ni8steelside.Thisisthekeyfactortoinducecrackatthisposition.Withtheenhancementofheatingtemperature,thepeakstressatthebondedinterfaceincreases.Whenthetemperatureis1100℃,thepeakstressisupto65.9MPa,whichisbiggerthanthatat1000℃by9.4%.Inaddition,thepeakstressbecomesbiggerwiththeincreaseofthethicknessofbasemetalfrom1mmto8mm.Whilethethicknessismorethan8mm,thepeakstressvariesslightlywiththechangeofthethickness.
简介:A60%Fe/Al2O3catalystwaspreparedbytheco-precipitationmethod.ItwasreducedbyH2toproducemetallicFe,whichwasthensulfidedbyCS2toFe0.96SandFe3S4orphosphidedbytriphenylphosphine(PPh3)inliquidphasestoFe2PandFeP.Itwasfoundthattheironsulfides(Fe0.96SandFe3S4)exhibitedthelowactivityforthehydrodesulfurization(HDS)reactions.TheHDSactivitywasalsolowontheFe(metal)/Al2O3andFe2P/Al2O3catalystssincetheywereconvertedintoFe0.96SandFe3S4duringtheHDSreactions.Incontrast,theFeP/Al2O3wasfoundtobestableandactivefortheHDSreactions.Inparticular,FeP/Al2O3possessedsignificantlysmallerFePparticlesthanFeP/C,leadingtothesignificanthigherHDSactivityofFeP/Al2O3thanFeP/C.
简介:Layereddoublehydroxides(LDHs)withhydrotalcite-typestructurecontainingFe3+,Al3+andMg2+werepreparedbymeansofacoprecipitationmethod.Theproductswerecharacterizedbyelementanalysis,X-raypowderdiffractionandtransmissionelectronmicroscopy.Itwasfoundthatevenifthemolarratioofn(Fe+Al)/n(Fe+Al+Mg)>0.33,yetapurehydrotalcite-likecompound(HTlc)phasewasgainedwhenn(Fe)/n(Al+Mg+Fe)≤0.30andn(Al)/n(Al+Mg+Fe)≤0.30;theAl(OH)3phaseappearedintheproductswhenn(Al)/n(Al+Mg+Fe)>0.30;andanamorphousphaseemergedwhenn(Fe)/n(Al+Mg+Fe)>0.33.TheseresultsshowthatthereisnoconcentrationsuperpositioneffectbetweenFe3+andAl3+onthecrystallinestateoftheproducedsamples.Inourpreviouswork,theconcentrationsuperpositioneffectbetweenZn2+andMg2+inthesynthesisofZn-Mg-Al-LDHswasfound.ForthepreparedFe-Al-Mg-LDHssamples,thevalueoflatticeparameteraisbetween0.30-0.32nm;andthevalueoflatticeparametercisbetween2.30-2.47nm,thebasalspacingisintherangeof0.76-0.83nm.Whentheratioofn(Fe)/n(Al)isaconstant,thevaluesofaandcincreasewiththeincreaseoftheMg2+contentoftheproducedsamples.Themeanparticlesizeandthemeancrystalgrainweredeterminedbyvirtueofaparticle-sizeinstrument,XRD-ScherrerformulaandTEMmethod,respectively.
简介:Theimplantedionrange,thedepthprofileandthefilmsttuctureoftheimplantedlayerwerestudied;thecarrierconcentrationandthemobilityweremeasured;theconductivitymechanismofthefilmimplantedFeintoAl2O3ceramicwasdiscussed.TheconclusionisthattheimplantedFe2+ionsmoveintoAl2O3latticeandreplaceAl3+toformsubs-titutionimpuritiessothattheionimplantedlat-tice,ascomparedwiththeoriginalone,presentsaneffectivenegativechargewhichformsanegativechargecenter.Avacancyisboundarroundit,andanacceptorisintroducedintheforbiddenband.
简介:ItisfundamentallyimportanttounderstandtheinfluenceofstrainonthedensityofdeformationtwinsinTWIPsteelbecausetwinningisitsdominantdeformationmechanism.ThedeformationbehaviorofaFe-30Mn-4Si-3Al-0.097CsteelhasbeeninvestigatedbyX-raydiffraction(XRD),electronbackscatterdiffraction(EBSD)andtransmissionelectronmicroscopy(TEM)techniques.Samplewithanaveragegrainsizeof10μmwasdeformedincold-rollingwithareductionof10%,20%,30%,40%,50%,60%and70%,respectively.Themechanicalpropertiesofthecold-rolledsampleswerefurtherinvestigatedbytensiletests.Theyieldstrength(σy)andultimate-tensile-strength(σUTS)oftheas-preparedsampleis480MPaand850MPa,respectively.However,undercoldrollingdeformation,thetensilestrengthobviouslyincreaseswithanincreaseinrollingreduction.Thesamplewitharollingreductionof10%exhibitsσyof610MPaandσUTSof-1000MPa.Theyieldstrengthandtensilestrengtharefurtherenhancedupto1320MPaand1378MPaforthespecimenwitharollingreductionof70%,regardlessofthepoorductilityof6.7%.ThedeformationmicrostructureswerestudiedbyEBSDandTEMobservations.Itisfoundthat,withincreasingrollingreduction,theaveragedistancebetweendeformationtwinsdecreasesgraduallywhilethedensityofdeformationtwins(thelengthoftwinboundaryinunitarea)exhibitamaximumvalueat40%cold-rolling+tension.Carefullystatisticsanalysisrevealsgrainorientationiscloselyrelatedtothedeformationtwinsandtheunderlyingmechanismgoverningthetwinningisdiscussed.
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简介:Inthisarticle,nano-scaleAl/Fe2O3compositeswithdifferentmorphologiesweresuccessfullyobtainedbyasimpleelectrospinningtechnique,whichisbasedonasurfactant(polyvinylpyridine,PVP)inamixtureofN,N-dimethylformamide(DMF)and2-propanol.TheelectrospunAl/Fe2O3compositesexhibitedacrystalstructureandphasecompositionbyX-raydiffractionanalysis.ThedifferentmorphologiesoftheAl/Fe2O3compositeswerealsoobservedthroughscanningelectronmicroscopyandtransmissionelectronmicroscopy.Itwasfoundthattherathersimpleelectrospinningmethodusedtopreparethemorphology-controlledAl/Fe2O3compositesmayhavethepotentialforpreparationofpropellants,explosives,andpyrotechnicsinthefuture.
简介:ThemicrostructureandcompositionofTiC-Al2O3/Fefunctionallygradedmaterials(FGM)preparedbyself-propagatinghightemperaturesynthesisandpseudo-hotisostaticpressing(SHS/PHIP)werestudied,andtheresistingthermalshockbehaviorswereanalyzed.TheresultsshowthatTiC-Al2O3/FeFGMhasgradedcompositiondistribution.Nocross-sectioncrackthroughthelayerswasfoundinthetestsofthermalshockandfatigue.
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简介:1.IntroductionLightrareearthadditioncanremarkablyenhancetheservicelifeofFe-Cr-Alalloyforelectricalheatingelement,butitscontentinthealloymustbecontrolledbelowthelevelof0.1wt-%.Whenthecontentexceedsthat,theperformance
简介:摘要:Ti-10V-2Fe-3Al合金是一种近β型钛合金,由于具有高强、高韧、高比强度、深淬透性和优良的热加工性在航空航天领域具有广泛的应用前景。与目前航空航天领域用量最大的Ti-6Al-4V合金相比,Ti-10V-2Fe-3Al合金的β转变温度一般为790℃~815℃,比Ti-6Al-4V合金的β转变温度大约低100℃。在β转变温度附近变形的流动应力与Ti-6Al-4V合金935℃变形的流动应力相当,可用于生产各类棒材、板材、锻件等产品,尤其适用于制造316℃以下工作的发动机零件。与锻造等加工工艺相比,热处理能够在不改变工件的尺寸结构和化学成分的前提下,有效改善工件内部的微观组织,最终获得优良的使用性能和工艺性能,达到提升产品质量、延长使用寿命的目的。
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简介:[摘要 ]本文采用颗粒状的 Al2O3负载 Fe2O3作为催化剂,对某制药厂制药废水经二级生化处理后的出水采取臭氧催化氧化法进行处理。通过实验对 Fe2O3/Al2O3催化剂的制备条件进行优化,确定焙烧温度为 600℃、焙烧时间为 4h、浸渍液浓度为 64g/L、浸渍时间为 8h时制成的催化剂的催化性能最佳。本研究中通过优化制备条件最终制成 Fe2O3/Al2O3催化剂,能为类似的实际工程提供技术指导和借鉴。
简介:通过铝热反应法分别制备未加Si和加Si的块体纳米晶Fe-Al-Cr和Fe-Al-Mn材料。利用OM,XRD,EPMA和TEM对制得的材料进行微观组织观察。结果表明:加入质量分数为5%的Si之后,2种材料的平均晶粒尺寸变化不大;含10%Cr的材料晶体结构没有发生变化,均由无序bcc结构组成,而含15%Mn材料的晶体结构由之前的有序D03结构向B2结构转变;Si元素的加入可降低Cr、Mn元素在Fe,Al中的溶解度,使基体中有Cr、Mn相析出。对材料进行硬度和应力应变曲线的测试,发现加入5%Si后,各材料的硬度均有较大程度的提高,塑性显著降低:含10%Cr的材料屈服强度由790MPa减小至642MPa,而含15%Mn的材料屈服强度由708MPa增大至808MPa。
简介:铝和铬的性质有不少相似之处.它们都是两性金属,既能溶于酸又能溶于强碱;都被冷的浓硝酸钝化,其氧化物Al2O3、Cr2O3都是熔点高、硬度大的物质,其氢氧化物Al(OH)3、Cr(OH)3都是难溶于水的两性氢氧化物,既能溶于酸又能溶于强碱.本文利用Al—H2O系统的(?)—pH图及Cr—H2O系统的(?)—pH图,对铝和铬及其氢氧化物的两性进行分析.一、Al—H2O系统(?)—pH图图1为Al—H2O系统的(?)—pH图,其作法是:(?)线代表H+/H2线.根据(?)(H+/H2)=-0.0592pH-(0.0592/2)1g(P(H2))