超低碳貝氏體鋼焊接接頭組織的微觀力學(xué)性能與EBSD分析.pdf

1、武漢科技大學(xué)碩士學(xué)位論文超低碳貝氏體鋼焊接接頭組織的微觀力學(xué)性能與EBSD分析姓名：魏然申請學(xué)位級別：碩士專業(yè)：等離子體物理學(xué)指導(dǎo)教師：吳開明20080530第1I頁武漢科技大學(xué)碩士學(xué)位論文AbstractThesteelwithhighstrengthandgoodtoughnesscanberealizedbytherefinementofitsmicrostructuresHoweverthepropertiesofweldjoi

2、ntofthesteelaretendedtobedeterioratedduetothecoarseningofmicrostructuresduringweldingofthesteelInthisthesis，thecharacterization，ElectronBackScatteredDiffraction(EBSD)analysisandmicromechanicalpropertiesofweldjointmicrost

3、ructuresofaultrafine—grainedhighstrengthsteelwerestudied，whichwasprocessedbyaTMCP(ThermomechanicalControlProcess)RPC(RelaxationPrecipitation—Controlledtransformation)techniqueMicrostructuralobservationsofweldjointofthest

4、eelwereconductedbymeansofopticalmicroscopyandscanningelectronmicroscopyTheweldjointconsistedofweldmetal，fusionregion，coarsegrainedregion，finegrainedregionandincompleterecrystallizationregionTheweldmetalwasmainlymadeupoff

5、ineacicularferriteThefusionregionwasmainlymadeupofbainiticferriteThecoarsegrainedregionwasmainlymadeupofbainiticferritepacketswhichconsistedofparallelbainiticferritelathsorplatesThefinegrainedregionconsistedoffinepolygon

6、alferritegrainsTheincompleterecrystallizationregionwasmadeupofthemixtureoffinerecrystallizedpolygonalferritegrainsandfinelathlikeorplate—likebainiticferritematrixSEMEDS(ScanningElectronMicroscopy—ElectronDispersedSpectru

7、m)observationsandanalysisofweldmetalwasConductedonafieldemissionscanningelectronmicroscopeResultsshowedthatseveralferritelathsorplateswerenucleatedononeinclusionTheinclusionConsistedofanA1203coreandanouterlayeroftitanium

8、oxideThenucleationofintragranularferritewaspromotedbytheformationofMndepletedzone，probablyduetoMndiffusionintotitaniumoxidebymeansofcationvacancies，ortothesolubilitydifferenceofMninferritematrixandininclusionEBSDanalysis

9、wasconductedwithaFESEMtoinvestigatethecrystallographicorientationofweldjointmicrostructuresResultsindicatedthatthecrystallographicorientationofacicularferritewasnotcompletelyrandomAcertaincrystallographicorientationwasdo

10、minantforacicularferriteAcicularferritewasseparatedbyhighangleboundariesSomeacicularferritelathsorplateswhichwereformedononeinclusionandgrewinoppositedirectionshadthesamecrystallographicorientation，presumablybecauseithad

11、somecrystallographicorientationrelationswiththepriorausteniteIncoarse—grainedregion，somebainiticferritepacketsgrewinacertaincrystallographicorientationweredominantamongthepacketsinapriorausteniteBainiticferritepacketsgre