简介:Anewroutetosynthesizenanosizedcrystallineof(La0.67–XGdX)Sr0.33MnO3(X=0.05,0.10,0.15,0.20)perovskite-typecomplexoxidesatcalcinationtemperatureof600-1000°Cusingtheamorphousmolecularalloyasprecursorswasreported.Theprecursorcouldbecompletelydecomposedintocomplexoxideattemperaturebelow500°CaccordingtotheTGAandDTAresults.XRDdemonstratesthatthedecomposedspeciesiscomposedofperovskite-typestructureatcalcinationtemperatureof600°Cfor2h.Theparticlesizethatdependsonthecalcinationtemperatureoftheprecursorisinarangeof30-120nmasdeterminedbytransmissionelectronmicroscopy(TEM).Thismethodiseffectiveandcanbeeasilyquantitativelycontrolledtosynthesizenanosizedperovskite-typecomplexoxides.Themagneticpropertiesof(La0.67–XGdX)Sr0.33MnO3nanocrystallinewerepreliminarystudied.
简介:喷洒的Zn和Zn15Al涂层被选择保护对的高张力水泥(PHC)的结束输送的金属的弧在东北中国在北瓷器和中立草地土壤对盐咸滩土壤的腐蚀堆。在二个模仿的土壤答案的涂的Q235钢样品的腐蚀行为被potentiodynamic极化和电气化学的阻抗光谱学(EIS)调查方法。试验性的结果证明在两个都模仿的答案的矩阵Q235钢的腐蚀被Zn和Zn15Al涂层显著地禁止。Zn和Zn15Al上的腐蚀产品厚、紧缩、坚挺、保护。Zn和Zn15Al涂的样品的腐蚀水流密度icorr与腐蚀时间,和费用转移电阻Rct显然被减少极大地被增加。在模仿的中立草地土壤答案的Zn和Zn15Al的腐蚀电阻索引是比在盐咸滩土壤的那些更突出的。在盐咸滩土壤的Zn15Al的腐蚀电阻比Zn的稍微优异。当喷洒的涂层与环氧基树脂树脂被封上时,涂层的腐蚀电阻进一步显著地被提高。
简介:在原处,TiB2/7055Alnanocomposites被制作由在高紧张下面从7055Al-K2TiF6-KBF4系统在situ融化化学反应超声的地,和机制和运动模型在原处融化化学反应被调查。X光检查衍射(XRD)和扫描电子显微镜(SEM)分析显示尺寸在原处TiB2nanoparticles在80120nm的范围。icewater的结果熄灭了整个过程包含的样品表演四个阶段,和外套在原处反应时间是10分钟。在里面situ合成过程主要被化学反应,并且由在以后的舞台扩散的微粒在更早的舞台(前者3分钟)控制。在在在7055Al-K2TiF6-KBF4系统超声的高紧张下面的Al3Ti和AlB2之间的关键反应的机制是reaction-diffusion-crack-rediffusion。而且,在7055Al-K2TiF6-KBF4系统的反应运动模型被建立。
简介:SiCp/AI金属矩阵的表面上的紧缩的氧化物合成(SiCp/AIMMC)极大地取决于关节的性质。镶嵌的劈啪作响的目标被使用由血浆侵蚀在SiCp/AIMMC的结合的表面上完全蚀刻氧化物。在厚度的5妈妈的Cu/Ni/Cu电影被磁控管劈啪作响方法在一样的真空房间在干净结合表面上准备,它在结合的短暂液相(TLP)作为夹层被扮演过程。与单个Cu陪衬和Ni陪衬夹层的一样的厚度相比,200MPa的shear力量在TLP结合期间用Cu/Ni/Cu电影夹层被获得,它是89.7%碱金属的。另外,结合的区域的
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简介:Anovel,Ti-6A1-4V(Ti64)/Hydroxyapatite(HAat5%byweightconcentration)metal/ceramiccompositehasbeenfabricatedusingelectronbeampowderbedfusion(EPBF)additivemanufacturing(AM):specifically,thecommercialelectronbeammelting(EBMR)process.InadditiontosolidTi64andTi64/5%HAsamples,fourdifferentunitcell(model)open-cellularmeshstructuresfortheTi64/5%HAcompositewerefabricatedhavingdensitiesrangingfrom0.68to1.12g/cm^3,andcorrespondingYoung'smodulirangingfrom2.9to8.0GPa,andcompressivestrengthsrangingfrom-3to11MPa.ThesolidTi64/5%HAcompositeexhibitedanoptimaltensilestrengthof123MPa,andelongationof5.5%incontrasttoamaximumcompressivestrengthof875MPa.Boththesolidcompositeandmeshsamplesdeformedprimarilybybrittledeformation,withthemeshsamplesexhibitingerratic,brittlecrushing.Solid,EPBF-fabricatedTi64sampleshadaVickersmicroindentationhardnessof4.1GPawhiletheTi64/5%HAsolidcompositeexhibitedaVickersmicroindentationhardnessof6.8GPa.ThelowestdensityTi64/5%HAcompositemeshstrutsectionshadaVickersmicroindentationhardnessof7.1GPa.Opticalmetallography(OM)andseanningelectronmicroscopy(SEM)analysisshowedtheHAdispersoidstobehighlysegregatedalongdomainorgrainboundaries,buthomogeneouslydistributedalongalpha(hcp)plateletboundarieswithinthesedomainsintheTi64matrixforboththesolidandmeshcomposites.Thealphaplateletwidthvariedfrom-5μmintheEPBF-fabricatedTi64to-1.1μmfortheTi64/5%HAmeshstrut.TheprecursorHApowderdiameteraveraged5μm,incontrasttothedispersedHAparticlediametersintheTi64/5%HAcompositewhichaveraged0.5μm.ThisworkhighlightstheuseofEPBFAMasanovelprocessforfabricationofatruecompositestructure,consistingofaTi64matrixandinterspersedandexposedHAdomains,whichtotheauthorsknowledgehasnotbeenreportedbefore.Theresultsalsoillustratetheprospectsnotonlyforfabrica
简介:TheevolutionofmicrostructureandmechanicalpropertiesofAl-0.4Cu-0.14Si-0.05Mg-0.2Fe(wt.%)alloys,micro-alloyedwithZr,TiandSc,wereinvestigated.Theadditionof0.2%ZrtobasealloyacceleratestheprecipitationofSi-richnano-phaseinα-Almatrix,whichplaysanimportantroleinimprovingthemechanicalpropertiesofanalloy.Thetensilestrengthincreasesfrom102MPaforthebasealloyto113MPafortheZr-modifiedalloy.Adding0.2%Zr+0.2%Titobasealloyeffectivelyrefinesa-AlgrainsizeandacceleratestheprecipitationofSiandCuelements,leadingtoheavysegregationatgrainboundary.Byfurtheradding0.2%SctoZr+Timodifiedalloy,thesegregationofSiandCuelementsissuppressedandmoreSiandCuprecipitatesappearedinα-Almatrix.AccompaniedwiththeformationofcoherentAl3Scphase,thetensilestrengthincreasesfrom108MPafortheZr+Timodifiedalloyto152MPafortheSc-modifiedalloy.DuetoexcellentthermalstabilityofAl3Scphase,theSc-modifiedalloyexhibitsobviousprecipitationhardeningbehaviorat350℃,andthetensilestrengthincreasesto203MPaafterholdingat350℃for200h.
简介:Highentropyalloyhasattractedincreasingattentions.However,toenhancethealloystrengthoftenleadstoimpairmentoftheductility,orviceversa.HerewereportedaheattreatmentapproachonAlCrFeNi2Ti0.5highentropyalloy,whichcanelevatethestrengthandductilitysimultaneously.AningotofAlCrFeNi2Ti0.5weighing2.5kgwasfirstlyfabricatedbymediumfrequencyinductionmelting.Thensamplesfromthesameheightofthebulkingotwereannealedfor6hat600,700,800and1000℃,respectively.After1000℃annealing,anoptimalmicrostructurewasobtainedbyusingourapproachwhichcanmakesomeprecipitationparticlesdistributehomogeneouslyinthedendriteinteriorwhilekeeptheinterdendritestructureasasinglesolidsolutionphase.ThemechanicaltestonthisAlCrFeNi2Ti0.5alloysampleshowedthat,thecompressivefracturestrengthσbcwasincreasedbyabout600MPaandtheplasticstrainepwasdoubled,comparedwiththoseoftheas-castsample.Ourapproachcanbereadilyadaptedtolarge-scaleindustrialproductionofhighentropyalloyswithhighstrengthandductilitybyproperannealingtreatment.
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简介:TheeffectoftitaniumadditiononthemicrostructureandmechanicalpropertiesofbrassCu40Znhasbeenstudiedviathepowdermetallurgy(P/M)route.Thewater-atomizedCu40Zn—1.0wt%Tialloypowderwasconsolidatedatdifferenttemperaturesintherangeof400—600℃usingsparkplasmasintering(SPS)andhotextrusionsubsequently.Resultsshowthatthesuper-saturatedsolidsolutiontitaniumelementinrapidlycooledbrassCu40Znpowdercreatedhighchemicalpotentialforaprecipitatereaction,showingsignificantgrainrefinementeffectsontheconsolidatedCu40Znmatrix.Consequently,excellentmechanicalpropertieswereobtainedbyprecipitationhardeningandworkhardeningaftersinteringandextrusion,withyieldstrengthof390MPa,ultimatetensilestrengthof617MPa,andVickersmicro-hardnessof192HV,whichare28.7%,23.4%,and23.9%highervaluesthanthoseofextrudedCu40Znbrass,respectively.
简介:采用机械球磨技术制备了MgH2-10%Al2O3(质量分数)储氢复合体系,通过XRD、SEM、DSC-TG等检测手段考查了微量Al2O3陶瓷颗粒掺杂对MgH2体系组织结构及解氢性能的影响,并对其相关机理进行了分析.结果表明:机械球磨可有效细化MgH2颗粒;在微量Al2O3陶瓷颗粒与机械球磨的协同作用下,MgH2颗粒的细化效果更为显著;相对于纯MgH2球磨体系而言,微量Al2O3的掺杂有效降低了MgH2体系的解氢温度(降低近50℃),且其解氢速率也有所提高;MgH2-Al2O3储氢复合体系解氢性能的改善主要源于Al2O3陶瓷颗粒对MgH2体系的组织细化效应.
简介:Throughmeasuringthecoefficientoflinearexpansion,thestructureandpropertiesoftheLi2O-Al2O3-SiO2lowexpansionglassceramicscontainingB2O3arestudiedbyJRandXRD.ItisshoutnthattheIRmethodisefficientinthestudyoftheglass-ceramicsstructure.Thereisa"Boronabnormality"inthesystemwhichhasanimportantinfluenceonthepropertiesoftheglass-ceramics.
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简介:Newvisibletransparent,UVabsorption,andhighinfraredreflectionpropertieshavebeenrealizedbydepositingmultilayerSiO2/ZnO:Al/CeO2-TiO2/SiO2filmsontoglasssubstratesatlowtemperaturebyradiofrequencymagnetronsputtering.OptimumthicknessofSiO2,ZnO:Al(ZAO)andCeO2-TiO2(CTO)filmsweredesignedwiththeaidofthinfilmdesignsoftware.Thedegreeofantireflectioncanbecontrolledbyadjustingthethicknessandrefractiveindex.TheouterSiO2filmcandiminishtheinterferencecoloringandincreasethetransparency;theinnerSiO2filmimprovestheadhesionofthecoatingontheglasssubstrateandpreventsCa2+,Na+intheglasssubstratefromenteringtheZAOfilm.Theaveragetransmittanceinthevisiblelightrangeincreasesbynearly18%-20%,ascomparedtodoublelayerZAO/CTOfilms.Andthefilmsdisplayhighinfraredreflectionrateofabove75%inthewavelengthrangeof10-25μmandgoodUVabsorption(〉98%)properties.Thesesystemsareeasytoproduceonalargescaleatlowcostandexhibithighmechanicalandchemicaldurability.ThetriplefunctionalfilmswithhighUVabsorption,antireflectiveandhighinfraredreflectionratewilladapttoapplicationinflatpaneldisplayandarchitecturalcoatingglass,automotiveglass,withdiminishinglightpollutionaswellasdecreasingeyefatigueandincreasingcomfort.
简介:来临三维(3-D)打印了技术在设定的多孔的钛(Ti)的制造提供大可能性植入。然而,打印Ti的bioinert性质提出一个突出的问题。混合微弧的氧化并且热水(MAO-HT)多孔的金属上的处理能生产multi-scaled层次矫形植入,为3-D的表面修正的出现大潜力打印了植入。在这研究,有毛孔的圆柱的多孔的Ti6Al4V(Ti64)脚手架640缩放吗??
简介:Ag-TiAlintermetallicalloy,Tie45Ale2Nbe2Mn(at.%)e0.8vol.%TiB2,hasbeenprocessedfromgasatomizedprealloyedpowderbyfieldassistedhotpressing(FAHP).Aninitialanalysisoftheprealloyedpowderhelpedontheunderstandingoftheintermetallicsinteringbehavior.Atomizedpowderconsistedofametastablephasethattransformedintoa2tgequilibriumphasesbythermaltreating.Differentpowderparticlemicrostructureswerefound,whichinfluencethemicrostructuredevelopmentoftheFAHPg-TiAlmaterialdependingonthesinteringtemperature.Duplex,nearlylamellarandfullylamellarmicrostructureswereobtainedatthesinteringtemperaturesabove1000C.Lowerconsolidationtemperatures,below1000C,ledtotheformationofanAlrichphaseatpowderparticleboundaries,whichisdeleterioustothemechanicalproperties.Highcompressiveyieldstrengthof1050MPawasobservedinsampleswithFAHPduplexmicrostructuresatroomtemperature.Whereasnearlylamellarandfullylamellarmicrostructuresshowedyieldstrengthvaluesof655and626MPaatroomtemperatureand440and425MPaat750C,respectively,whicharesuperiorincomparisontosimilaralloysprocessedbyothertechniques.Theseexcellentpropertiescanbeexplainedduetothedifferentvolumefractionsofthea2andgphasesandtherefinementofthePMmicrostructures.