Inconel 740H合金原位高温拉伸微裂纹萌生扩展研究.docx

Inconel740H合金原位高温拉伸微裂纹萌生扩展研究
Abstract
Inconel740Halloyisahigh-temperaturenickel-basedalloythatshowsgreatpotentialforuseinhigh-temperatureapplications,suchaspowergenerationequipment.However,itsmechanicalpropertiesunderhightemperaturesarenotwellunderstood,particularlythebehaviorofmicrocracksunderstrain.Therefore,thepresentstudyaimstoinvestigatethebehaviorofmicrocracksinInconel740Halloyunderhigh-temperaturetensiletesting.Theresultsshowedthatthemicrocracksinitiatedatthegrainboundariesandpropagatedinatransgranularmanner.Thegrainboundarystructureplayedanimportantroleintheinitiationandpropagationofmicrocracks.Thesefindingshaveimportantimplicationsforthedesignandselectionofmaterialsforhigh-temperatureapplications.
Introduction
Inconel740Halloyisanewnickel-basedalloythathasbeendevelopedforuseinhigh-temperatureapplications,suchasboilers,turbines,andnuclearreactors.Thealloyhasexcellenthigh-temperaturestrength,creepresistance,andcorrosionresistance,makingitanattractivematerialforpowergenerationequipment.However,thereisalackofinformationaboutthebehaviorofmicrocracksinInconel740Halloyunderhigh-temperatureconditions,particularlyduringtensiletesting.
Inthisstudy,thebehaviorofmicrocracksinInconel740Halloyunderhigh-temperaturetensiletestingwasinvestigated.Theaimofthisstudywastorevealthemicrocrackinitiationandpropagationbehavior,andtoprovideabetterunderstandingofthemechanicalpropertiesofthisalloyunderhigh-temperatureconditions.
ExperimentalMaterialsandMethods
TheInconel740Halloyusedinthisstudywasproducedbyacommercialmanufacturer,andthechemicalcompositionislistedinTable1.ThesamplesfortensiletestswerepreparedasperASTME8Mstandard,withagaugelengthof20mmandawidthof4mm.Tensiletestswereconductedusingauniversaltestingmachineatatemperatureof800°C,andastrainrateof10^-4s^-1.Thesurfacesofthesampleswereobservedusingopticalmicroscopyandscanningelectronmicroscopy(SEM).
ResultsandDiscussion
TheInconel740Halloydisplayedsignificantcreepdeformationduringthetensiletestsat800°C.Thegrainsizeofthealloywasob