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1、西北工业大学硕士学位论文摘要Abstract3D-C/SiCisanewkindofpromisingthermal-structuralmaterialinaviationandaerospacefield.Sofar,manystudiesongeneralpropertiesof3D-C/SiChavebeencarriedout,butthestudyonitsinteractionfatigue-creepandthermalshockbehavior,especiallyathightemperature,hasnotbee
2、nreported.Therefore,asystemicandin-depthstudyisofsignificantimportanceforimproving,engineeringdesignandapplicationof3D-C/SiContheinteractionfatigue-creepandthermalshockproperties.Thermalshockbehaviorandinteractionfatigue-creepof3D-C/SiChadbeeninvestigatedinthethreeenviro
3、nments(Argon,dryoxygen,wetoxygen)inthepresetwork.3D-C/SiCfabricatedwithT300carbonfibersweavedinto3-dimensionaland4-directionalstructure,wasdepositedpyrocarbonandSiCmatrixat950-10000withCVImethod.Fibervolumefractionof3D-C/SiCwas40-450/a,compositedensitywas2.0jg/cm3andporo
4、sitywas17%.Inaddition,thethicknessofpyrocarboninterfacewas200amforinteractionfatigue-creep;theinterfacelayerofpyrocarbonforthermalshockhadthreethicknessobtainedbycontrollingdepositiontimewhichwere10h,20h,30h,respectively.Theresultsindicatedthatthermalshockcurveevaluatedb
5、yYoung'smoduluswassimilartothatbyelectricalresistance,andtheyapproximatelyconsistedofthreestages,thatis,therapiddamagestage,thestabledamagestage,andthenthedamagesharplyacceleratedstage.However,exceptionalthermalshockcurveexpressedbyelectricalresistanceonlyoccurredtodropi
6、ntheinitialstage.Moreover,thermalshockbehaviorof3D-C/SiCwasdistinctlysuperiortothatofrecrystallizationSiC,andwhenthedepositiontimeofpyrocarbonwas20h,3D-C/SiCpossessedthelongestthermalshocklife.Inthethermalshockunderairmedium,amaindamageformof3D-C/SiCwasthatoxidationofcar
7、bonfibershadbeencausedbypeel-backofcarborundumcoating.西北工业大学硕士学位论文摘要For3D-C/SiCcomposite,theoveralltendencyofmoduluswasdiminishingwithincreasedcyclenumber.Theinteractionfatigue-creepdamageevaluatedbyelectricalresistancepossessedthreestages,includingthedecelerateddamagest
8、ageinitiatively,thestabledamagestage,andthenthesharplyaccelerateddamagestagefinally.Andinthethreemedium
