钛铝合金表面涂层工艺与高温抗氧化性能的试验研究

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1、南京航空航天大学硕士学位论文钛铝合金表面涂层工艺与高温抗氧化性能的试验研究姓名：陈志勇申请学位级别：硕士专业：机械制造及其自动化指导教师：黄因慧20080601钛铝合金表面涂层工艺与高温抗氧化性能的试验研究AbstractTiAlintermetallicsalloys(TiAlalloyforshort)arenewtypehightemperaturestructuralmaterialsappliedforaerospaceandaircraftindustriesbecauseoftheirlowdensity,highstrengthandg

2、oodcreepresistance.Theproblemofpoorductilityofthesematerialsatroomtemperaturehasbeenmostlysolvedbyalloyingandmicrostructurecontrolling.Thustheproblemoffartherimprovinghigh-temperatureoxidationresistancehasbecomeoneofthemostimportantresearchsubjects.Inthispaper,high-temperatureox

3、idationresistanceofseveralcoatingsfabricatedbydifferenttechniquesonTiAlalloywasresearched.Thesurfacemorphology,microstructureandphaseofthecoatingsbeforeandafteroxidationwereinvestigatedusingscanningelectronmicroscope(SEM),energydispersivespectroscopy(EDS)andX-raydiffractometry(X

4、RD).Theoxidationmechanismofthedifferentcoatingswasalsodisscusedbasedontheoxidationkinetics,oxidesmorphologyandmicrostructure,etc.(1).High-temperatureoxidationbehaviorofdoubleglowplasmasurfacechromizedlayerswasstudied.TheresultsshowedthatacompactCr2O3oxidefilmwasformedonthesurfac

5、eofthechromizedlayerafterhigh-temperatureoxidation.Althoughtheoxidelayerappearedlocalspallingphenomenonafteralong-termoxidation,anewCr2O3layercanbereformedsoon.Therefore,thechromizedlayerhadagoodhigh-temperatureoxidationresistance.(2).High-temperatureoxidationresistanceofNiCoCrA

6、l-Y2O3coatingspreparedbythetechnologiesoftheplasmasprayingandplasmaspraying-laserremeltingwasanalyzed.Theresultsshowedthatplasma-sprayedNiCoCrAl-Y2O3coatinghadsomedefects,suchasloose,porousandmicrocrack.Thecoatinghadahighercompactness,thelamellarstructureofplasma-sparyedcoatingw

7、aseliminatedandthebondstatebetweenthecoatingandsubstratebecamemetallurgicalcombinationfrommechanicalcombinationafterlaserremelting.Sothelaser-remeltedsamplehadbetterhigh-temperatureoxidationresistancethantheplasma-sprayedcoatingdid.(3)High-temperatureoxidationbehaviorofconventio

8、nalandnanostructuredthermalbarriercoatings(TBCs