简介:Nb-24Ti-18Si-2Al-2Hf-4CrandNb-24Ti-18Si-2Al-2Hf-8Cralloyswerepreparedbyarcmeltinginawater-cooledcrucibleunderargonatmosphere.Microstructuralcharacteristicsandoxidationresistanceofthealloysat1250℃wereinvestigated.Theresultsshowthat,whentheCrcontentis4at%,themicrostructuresconsistof(Nb,Ti)_(ss)andNb_5Si_3;asCrcontentincreasesto8at%,C14LavesphaseCr_2Nbisformed.Theisothermaloxidationtestsshowthattheoxidationkineticsofthetwoalloysfollowsimilarfeatures.Theweightgainsofthetwoalloysafteroxidationat1250℃for100hare235.61and198.50mg·cm~(-2),respectively.Duringoxidation,SiO_2,TiO_2,Nb_2O_5andCrNbO_4areformedatfirst.Then,Ti_2Nb_(10)O_(29)isformedafteroxidationfor20minandbeginstochangeintoTiNb_2O_7astheoxidationproceeds.SiO_2isformedassolidstateatfirstbutlaterevolvesintoglassystatetoimprovethecohesionofthescale.Afteroxidationfor100h,oxidationproductsconsistofSiO_2,TiNb_2O_7,Nb_2O_5andCrNbO_4.
简介:ATi/Sicomplexzeolitehasbeenprepared.X-raydiffractionandinfraredspectrometrystudyhasshownthattwostructures,namelytheZSM-5andMCM-41,existinthesample.BETtestshaverevealedthatthecomplexzeolitecontainsregularmesoporesof2.6nm.UltravioletspectrometryanalysishasshownthattheTispeciesexistinthezeoliteskeletonintheformoftetra-coordinatevalence.TheTi/Sicomplexzeolite(TS-1/Ti-MCM-41)hasapparentlyimprovedcatalyticactivitywithrespecttothemacromolecularorganiccompoundoxidationascomparedtoindividualcomponentsofeitherTiorSicontainingzeolites(TS-1andTi-MCM-41).
简介:Vanadiumalloys(V-Cr-Tiseries)areimportantcandidatematerialsforblanketcomponentsoffusionreactorsduetotheirlowactivationandhighstrengthatelevatedtemperatures.Low-temperatureirradiationembrittlementdeterminestheoperationtemperaturelimitofVanadiumalloysfortheapplicationtostructuralmaterialsoffusionreactorsirradiationresponseofvanadiumalloysneedstobeclarifiedfortheirapplication.Inthepresentstudy,specimensoftwoalloys(V-4Cr-4TiandV-5Cr-5Ti)wereirradiatedwithenergeticHeionsandheavyionstounderstandhardeningofthealloysduetoheliumaccumulationandcascadedamageproduction.
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: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:Inordertoutilizetheadvantageofoxidesinstainlesssteel,theformationoftitaniumnitride(TiN)andoxide(TixOy)inthe17CrsteelwasinvestigatedbythecalculationofthefreeenergyofreactionandthermodynamiccalculationwithThermo-calcsoftware.Theresultindicatesthatthecompetitivereactionbetweenthedissolved[O]andthedissolved[N]withthedissolved[Ti]inmoltensteelresultsindifferentprecipitationsequencesofTiNandTixOy.TheprimaryprecipitationofTiNrequiresalow[O]andtheprimaryprecipitationofTixOyrequiresalow[N].Theincreaseof[Ti]causesahigherprecipitationtemperatureofTiNandTixOyinbothTi-NandTi-Oalloysystems.Equilibriumrelationsof[Ti]vs[N]and[Ti]vs[O]showthatthesolubilityproductsfallwiththedecreaseofthetemperature,andthentheprecipitationoftheinclusionsbecomeseasier.IntheTi-Oalloysystem,ahigh[O]andalow[Ti]arefavorabletotheprecipitationofTi3O5,andahigh[Ti]contentandalow[O]favorabletotheTi2O3precipitation.
简介:三不同Ti-Si氧化物structuares,硅石支持了titania,硅石涂的titania和亲密地混合的silica-titania,包含10%-40%SiO2,被nanocrystalline(nc)的微观结构参数的sol-gelprocess.The变化在二进制氧化物的三kirds成为TiO2锐钛矿包括在里面飞机间距d,电池常数(a0,C0),房间体积V,房间轴比c0/a0和水晶谷物缩放,被高决定传播电子显微镜学(HRTEM)和X光检查衍射(XRD)比较地调查。微观结构参数与增加SiO2内容显著地变化,这被发现,annealingtemperature.Different组织了Ti-Si二进制氧化物导致微观结构参数的不同变化趋势。二进制氧化物包含越多SiO2,ncTiO2锐钛矿的缺点越格子出现;Si阳离子的散开或移植能是在微观结构的变化的一个重要有影响的因素。在三种二进制氧化物的ncTiO2的谷物尺寸不仅取决于SiO2内容和退火的温度而且在ncTiO2-anatase.Both谷物尺寸和nc的阶段转变的格子microstrainand失真的度上,TiO2锐钛矿是有效地与增加SiO2内容禁止了。
简介:Therearemoreandmorecountriestoakeanefforttothestudiesofvanadiumalloyforfusionapplication.NIFSinJapanhasrecentlydevelopedan80kgheatV4Cr4Tialloy(NIFS-heat2)aftertheproductionofa500kgscaleV4Cr4TiinU.S.severalyearsago.PropertyevaluationofthealloyhasbeenputintoaninternationalcollaborationprogramunderthecoordinationofIEA(InternationalEnergyAgency).SWIPhasjoinedthecollabrationonthehydrogenembrittlementresistanceevaluationofthealloyt.
简介:Abstract:TheeffectofTiandNbontherecrystallizationandtherecrystallizedgrainsizeofthehot-rolledplatesandcold-rolledsheetsofultralowcarbonandnitrogen(ULCN)Cr18ferriticstainlesssteel(FSS)isinvestigated.Theresultsshowthattherecrystallizationofhot-rolledplatesandcold-rolledsheetswith0.29%Nbisdelayed,andtherecrystallizedgrainsaresignificantlyrefined.
简介:热等静压(HotIsostaticPress,HIP)技术是在惰性气氛中,在各向均衡的气体高压力及高温共同作用下,去除材料内部的孔洞及缺陷,以改善机械性质、使粉末材料及表面蒸镀物具一致性、通过扩散键结(diffusionbonding)改善焊接完整性等。热等静压适用于多种材料及器件,特别是铝合金、工具钢、钛、超合金以及蒸汽涡轮零件、医学植入件、自动化铸件、靶材与粉末冶金制品等。考虑到近年来随着高密度、高传输速率光储存媒体及平面显示器的发展,靶材的研究与开发,巳成为光学薄膜制造的关键技术,该文作者以热等静压方法改善金属靶材,比较热等静压前后靶材性质差异和论证批量生产的可行性;并探讨热等静压处理对靶材性质的影响、比较其显微结构变化,以评估热等静压改善金属靶材材之可行性。研究结果显示,利用l100℃,175MPa,4h热等静压的制备流程条件,对3种不同成分配比之Cr-Si热压靶材进行热等静压处理,均可有效改善孔隙率,其中以50Cr-50Si的热等静压效果最为显著,孔隙率可有效降低60%。此外,靶材在经过热等静压后,由于炉内气体的纯化效应而使得靶材的氮、氧浓度皆有所上升,尤其是Si以单独元素形态存在时更甚,从而造成靶材纯度受到影响。