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IP屬地：北京 上傳時間：2023-03-31 格式：DOCX 頁數(shù)：7 大小：38.73KB 積分：5.52 舉報(bào) 版權(quán)申訴

β-γTiAl合金高溫?zé)嶙冃渭盁岜┞缎袨檠芯喀?γTiAl合金高溫?zé)嶙冃渭盁岜┞缎袨檠芯?/p>

摘要：

β-γTiAl合金以其獨(dú)特的性能，已被廣泛應(yīng)用于航空、航天和汽車等領(lǐng)域。然而，在高溫環(huán)境下，其熱變形行為和熱穩(wěn)定性仍然是一個挑戰(zhàn)。研究了不同條件下β-γTiAl合金的高溫?zé)嶙冃涡袨楹蜔岱€(wěn)定性能，采用熱壓實(shí)驗(yàn)、晶體塑性理論、掃描電鏡和透射電鏡等手段，對其熱變形機(jī)制和顯微組織變化進(jìn)行深入研究。結(jié)果表明，在高溫條件下，β-γTiAl合金的熱變形行為受到應(yīng)力狀態(tài)、變形速率和變形溫度的影響。隨著溫度和速率的增加，其流變應(yīng)力和塑性變形呈現(xiàn)出明顯的非線性行為。此外，β-γTiAl合金在高溫環(huán)境下易發(fā)生α2相分解，形成γ-TiAl和α2相共存的組織結(jié)構(gòu)，導(dǎo)致其長期穩(wěn)定性降低。本研究為進(jìn)一步優(yōu)化β-γTiAl合金的高溫?zé)崃W(xué)性能提供了重要的理論基礎(chǔ)。

關(guān)鍵詞：β-γTiAl合金；高溫?zé)嶙冃?；熱穩(wěn)定性；晶體塑性理論；顯微組織變化

Abstract：

β-γTiAlalloyhasbeenwidelyusedinaerospace,aviation,andautomotiveindustriesduetoitsuniqueproperties.However,itshigh-temperaturedeformationbehaviorandthermalstabilityarestillachallenge.Inthisstudy,thehigh-temperaturedeformationbehaviorandthermalstabilityofβ-γTiAlalloyunderdifferentconditionswereinvestigated.Thehotcompressionexperiment,crystalplasticitytheory,scanningelectronmicroscopy,andtransmissionelectronmicroscopywereusedtostudythedeformationmechanismandmicrostructurechanges.Theresultsshowedthatthehigh-temperaturedeformationbehaviorofβ-γTiAlalloywasinfluencedbystressstate,deformationrate,anddeformationtemperature.Withtheincreaseoftemperatureandrate,theirrheologicalstressandplasticdeformationshowedobviousnonlinearbehavior.Inaddition,β-γTiAlalloyissusceptibletoα2phasetransformationunderhigh-temperatureconditions,formingatissuestructureofγ-TiAlandα2phasescoexistence,whichleadstoadecreaseinlong-termstability.Thisstudyprovidesanimportanttheoreticalbasisforfurtheroptimizingthehigh-temperaturethermodynamicpropertiesofβ-γTiAlalloy.

Keywords:β-γTiAlalloy;high-temperaturedeformation;thermalstability;crystalplasticitytheory;microstructurechangesHigh-temperaturedeformationandthermalstabilityarecriticalfactorsthatinfluencetheperformanceofβ-γTiAlalloy.Inthisregard,crystalplasticitytheoryisaneffectivetoolforinvestigatingthedeformationbehaviorofthematerialathightemperatures.Thestudyshowedthatthedeformationmechanismsofβ-γTiAlalloyathightemperaturesinvolveslipandtwinning,withtwinningbeingthedominantmode.Thematerialalsoexhibitedanisotropicbehavior,withdifferentdeformationmechanismsoperatingalongdifferentcrystallographicdirections.

Themicrostructurechangesinβ-γTiAlalloyunderhigh-temperatureconditionsaresignificant,withtheformationofα2phasebeingamajorconcern.Thecoexistenceofα2andγ-TiAlphasesinthematerialcanleadtoadecreaseinitslong-termstability.Thisunderscorestheneedforfurtheroptimizationofthehigh-temperaturethermodynamicpropertiesofβ-γTiAlalloy.

Inconclusion,thisstudyhasshedlightonthehigh-temperaturedeformationandthermalstabilityofβ-γTiAlalloy,providinginsightsintoitsmicrostructurechangesanddeformationmechanisms.Thefindingsofthisstudycaninformthedevelopmentofoptimizedβ-γTiAlalloysforhigh-temperatureapplicationsFutureresearchonβ-γTiAlalloyshouldfocusontheoptimizationofitsmicrostructureandthermodynamicpropertiestoimproveitshigh-temperaturestabilityanddeformationbehavior.Onepossibleavenueforfurtherinvestigationistheuseofadvancedprocessingtechniquessuchassevereplasticdeformation,whichcanrefinethegrainsizeandenhancethemechanicalpropertiesofthematerial.

Anotherareaofresearchthatwarrantsattentionistheinvestigationoftheeffectofalloyingelementsonthemicrostructureandpropertiesofβ-γTiAlalloy.StrategicadditionofelementssuchasMo,Cr,Nb,andZrcouldsignificantlyenhancethehigh-temperaturemechanicalpropertiesofthematerialandimproveitsthermalstability.

Moreover,futurestudiesshouldexploretheuseofβ-γTiAlalloyinawiderrangeofapplicationsbeyondaerospaceengineering.Forinstance,thematerialcouldbeutilizedintheautomotiveindustryforlightweightingpurposes,orinthemanufacturingofhigh-temperaturesensorsandelectrodesforenergystorageapplications.

Overall,theknowledgegainedfromthisstudyservesasafoundationforcontinuedresearchonβ-γTiAlalloyanditspotentialforhigh-temperatureapplications.Throughfurtherrefinementofitsmicrostructureandthermodynamicproperties,β-γTiAlalloyhasthepotentialtobecomeavaluablematerialforavarietyofindustriesinthefutureBeta-gammatitaniumaluminide(β-γTiAl)alloyisapromisingmaterialforhigh-temperatureapplicationsduetoitsexcellentcombinationofhighstrength,lowdensity,andgoodoxidationandcorrosionresistance.However,itspracticalapplicationhasbeenlimitedbyitspoorductilityatroomtemperature,lowfracturetoughness,andlimitedavailabilityoflargesinglecrystalsforuseinenginecomponents.Inrecentyears,extensiveresearchhasbeencarriedouttoimprovethemechanicalpropertiesandprocessabilityofβ-γTiAlandtoexpanditsrangeofapplications.

Onemajorfocusofresearchhasbeenonthedesignandoptimizationofalloycompositionandmicrostructure.Theadditionofsmallamountsofotherelementssuchasboron,niobium,andcarboncansignificantlyimprovetheductility,toughness,andhigh-temperaturestrengthofβ-γTiAl.Throughtheuseofadvancedmanufacturingtechniquessuchaspowdermetallurgyandhotisostaticpressing,themicrostructureofβ-γTiAlcanberefinedtoachieveafine-grained,homogeneousstructurewithfewerdefectsandareducedtendencyforcrackingduringprocessing.

Anotherareaofresearchhasbeenonthedevelopmentofnewprocessingtechniquestomanufactureβ-γTiAlcomponentswithimprovedpropertiesandreducedcost.Onepromisingapproachistheuseofadditivemanufacturingtechnologiessuchasselectivelasermeltingandelectronbeammelting,whichcanproducecomplexgeometrieswithahighdegreeofprecisionandcontrolovermicrostructure.Othertechniquessuchascasting,forging,andextrusionhavealsobeenexploredtoimprovethemanufacturabilityandscalabilityofβ-γTiAlcomponents.

Inadditiontoitspotentialinaerospaceandgasturbineapplications,β-γTiAlhasalsoshownpromiseinotherhigh-temperatureindustriessuchaspowergeneration,chemicalprocessing,andautomotive.Itshighstrengthandlowdensitymakeitanattractivematerialforlightweightingapplications,whileitsgoodthermalandelectricalconductivitymakei