简介:ThehotrollingexperimentinvestigatesintotherelationshipbetweenthemicrostructuresandthemechanicalpropertiesofNb-TimicroalloyedsteelswithvariousTicontents.TheresultsindicatethattheeffectofthebainitefractionofNb-TimicroalloyedsteelsontheyieldstrengthofthesteelsisnotrelatedtoTicontent,whiletheslopeoftheHall-PetchrelationshipdecreaseswiththeincreaseofTicontent.Accordingly,theMisramodelfortheyieldstrengthofNb-Timicroalloyedsteelsismodified,andthefactorswhichcausethechangeintheslopeofHall-Petchrelationshiparediscussed.
简介:ThemorphologiesevolutionofvarioustypesofinclusionsinTi-IFsteelwereobservedbyaspecialdeptherosionmethod,andtheformationandevolutionprocesswerediscussed.TheresultsshowedthatthemaininclusionswereFeO·xMnObeforeAldeoxidizationandtheratioofintegratedoxygenandfreeoxygenwasinrangedof0.3to0.4.Inpresentstudy,themaineffectfactorsonthemorphologiesofAl2O3inclusionswere[Al]/[O]Free(solublealuminumdividefreeoxygen)andinitialfreeoxygen;clusterAl2O3wasformedeasilywithhighfreeoxygen([O]Free)andlow[Al]/[O](blew3inpresentstudy).Otherwise,thedendriticAl2O3wasformed;coral-likeAl2O3wasthemixtureofthedendriteAl2O3andsphericalAl2O3.SomeAl2O3·TiOxinclusionsappearedbecauseahigh[Ti]concentrationregionexistedaround70TiFe(containing70percenttitanium)particlesafter70TiFeaddition.ThemaximumsizesofAl2O3reached800μmwhen3minaluminumwasadded;asthetimepast,thelargesizeAl2O3decreasedsignificantly;themaximumsizeofAl2O3wasblew100μmand50μmincalmingsampleandtundishsamplerespectively.
简介:MicrostructuralevolutionofinfraredvacuumbrazedCP-TiusingtwoTi-basedbrazealloys,Ti-15Cu-15NiandTi-15Cu-25Ni,hasbeeninvestigated.TheinfraredbrazedjointconsistedofeutecticTi2Cu/Ti2NiintermetalliccompoundsandTi-richmatrix.TheeutecticTi2Cu/Ti2Niintermetalliccompoundsdisappearedfromthejointafterbeingannealedat900Cfor1h.Incontrast,thedepletionrateofbothCuandNifromthebrazealloyintoCP-Tisubstrateat750Cannealingwasgreatlydecreasedascomparedwiththatannealedat900C.BlockyTi2Cu/Ti2Niphaseswereobservedevenifthespecimenwasannealedat750Cfor15h.BecausetheNicontentoftheTi-15Cu-25NibrazealloyismuchhigherthanthatoftheTi-15Cu-15Nialloy,theamountofeutecticTi2Cu/Ti2NiphasesinTi-15Cu-25NibrazedjointismorethanthatinTi-15Ci-15Nibrazedjoint.However,similarmicrostructuralevolutioncanbeobtainedfromtheinfraredbrazedjointannealedatvarioustemperaturesand/ortimeforbothfillermetals.
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简介:Inthepresentwork,anovelhybridcompositecomposedofTi-aluminidemulti-layeredpartandcontin-uous-SiCf-reinforcedTi-matrixpartusingavacuumhotpressing/hotisostaticpressure(VHP/HIP)sinteringprocesswassynthesized.Then,thedamagetolerancebehaviorofthishybridcompositewasstudiedbytensiletestsandinsituscanningelectronmicroscopy(SEM)three-pointbendingtests.Theresultsindicatethatthemechanicalpropertiesandcrackpropagationofthehybridcompositearestronglyinfluencedbytheextrinsictoughnessmecha-nism.Indetail,thecrackdeflectionofmulti-layeredcompositeandstrengtheningeffectofSiCf-reinforcedmatrixcompositeareobservedinthehybridcomposite.Owingtothestrengtheningeffectofcontinuous-SiCrre-inforcedTi-matrixpart,thetensilestrengthofhybridcompositeismuchhigherthanthatofneatTi-aluminidemulti-layeredcomposite.Furthermore,itisfoundthattheoptimaldamagetoleranceabilityisoptimizedwhenthenotchpositionislocatedattheTi-aluminidemulti-layeredpartduetothecrackdeflectionofmulti-layeredstructure.
简介:以便获得两高电镀物品迁居(他们)在高周波的表面的可靠性和罚款维的控制声学的波浪(锯)设备,4-layeredTi/Al-Mo/Ti/Al-Mo电极电影在128°Y-XLiNbO3上被调查由劈啪作响的底层免职。结果显示4-layered电影与常规Al-0.5wt.%Cu电影相比有改进他们可靠性。他们的一生比在5×的当前的密度测试的Al-0.5wt.%Cu电影的长约三倍107A/厘米2和200°C的温度。而且,4-layered电影容易在反应离子蚀刻被蚀刻,罚款维的控制为高周波的锯设备在模式复制期间被认识到。为4-layered电影,最佳瞬间数量和劈啪作响的参数为高他们可靠性是很重要的。
简介:摘要:采用Ti-36.5Zr-10Ni-15Cu-0.5Co-0.5Nb钎料对Ti2AlNb合金和Ti60合金进行真空钎焊,获得了良好的接头。研究了钎焊温度和保温时间对Ti2AlNb/Ti-36.5Zr-10Ni-15Cu-0.5Co-0.5Nb/Ti60钎焊接头的组织演变和力学性能的影响。接头区域内存在连续的金属间化合物,这类相在某种程度上促进了界面的冶金结合,但对接头整体的机械性能带来了不利的影响。随着钎焊温度和保温时间的提高,加速了液态钎料向基体的扩散,导致(Ti, Zr)2(Cu, Ni)脆性金属间化合物减少。在900℃下钎焊15min后,接头的抗拉强度达到最大值300.75Mpa,接头的断裂位置为(Ti, Zr)2(Cu, Ni)脆性相。通过调控钎焊温度和保温时间可以在一定程度上改善接头的微观组织结构,改善接头的机械性能。