TC4合金表面雙輝等離子滲鉻層與鉻氧共滲層的制備及性能研究.pdf

1、南京航空航天大學碩士學位論文TC4合金表面雙輝等離子滲鉻層與鉻氧共滲層的制備及性能研究姓名：崔宏申請學位級別：碩士專業(yè)：材料加工工程指導教師：駱心怡201103南京航空航天大學碩士學位論文vAbstractTitaniumalloysarewidelyusedinmanyfieldssuchasaerospacenavigationmedicaltreatmentduetohighstrengthtodensityratiogoodcr

2、osionresistanceexcellentbiocompatibility.Howeverthefurtherapplicationsarelimitedowingtotheirlowhightemperatureoxidationresistancepohotcrosionresistancepocrosionresistancefreducingsolution.Therefeitwasproposedinthisdisser

3、tationtopreparechromiziedlayerCrOmodifiedlayeronTC4alloybyusingthedoubleglowplasmaalloyingtechniqueindertoimprovehightemperatureresistanceoxidationhotcrosionresistanceelectrochemicalcrosionresistance.ThechromizedlayerCrO

4、modifiedlayeronTC4alloywasfabricatedbyusingthedoubleglowplasmaalloyingtechniqueinthispaper.thogonalexperimentsofL9(34)werecarriedoutfpreparationofchromizedlayertheoptimumtechnologicalparameterswereobtainedasfollows:sourc

5、evoltage950Vwkpiecevoltage300Vairpressure35Padistancebetweentwocathodes12mmholdingtime2hWhilethechosentechnologicalparametersfCrOmodifiedlayerwere:sourcevoltage600Vwkpiecevoltage450Vairpressure35Padistancebetweentwocatho

6、des12mmratioofoxygenargongaspressure1:6chromizingtime3hholdingtime2h.Themicrostructureofthepreparedmodifiedlayerswasacterizedrespectivelybymeansofscanningelectronmicroscope(SEM)energydiffractionspectroscopy(EDS)Xraydiffr

7、action(XRD).Theresultsshowedthatthemodifiedlayerswereunifmcompactcontinuous.BesidesthechromizedlayerwasmadeupofCrTiAl1xTi1xwhileCrOmodifiedlayerwascomposedofCrCr2O3Cr2Ti.Thethermalshocktestscratchtestshowedthatasprepared

8、modifiedlayerswerebothcloselybondedtothesubstrate.IthasbeensystematicallystudiedfhightemperatureoxidationresistancehotcrosionresistanceelectrochemicalcrosionresistanceoftheasfabricatedchromizedlayerCrOmodifiedlayeronTC4a

9、lloy.Hightemperatureoxidationtestsat800℃showedthatoxidationmassgainrateofthemodifiedlayermadeattheoptimumtechnologicalparameterswasmuchlowerthanthatofTC4substrate.BecausecompactCr2O3generatedathightemperatureoxidationcou

10、ldpreventfromfurtherincursionofoxygeneffectivelygreatlyimprovinghightemperatureoxidationresistanceofthesubstrate.ThehotcrosiontestsshowedthetwomodifiedlayerswerebothmadeupofCr2O3TiO2(Cr0.88Ti0.12)2O3themassgainofthemodif