TiC彌散強(qiáng)化鋼組織性能研究.pdf

1、東南大學(xué)博士學(xué)位論文TiC彌散強(qiáng)化鋼組織性能研究姓名：吳錢林申請(qǐng)學(xué)位級(jí)別：博士專業(yè)：材料學(xué)指導(dǎo)教師：孫揚(yáng)善20090521摘要MicrostructureandPropertiesofTiCdispersionStrengthenedSteelsAbstractThreeTiCdispersionstrengthenedsteelsbaseoncommoncarbonsteels2Crl3and304(0Crl8Ni9)stainles

2、ssteelshavebeenpreparedbyinsitureactionduringmeltingprocessing，andtheelectroslagremelting(ESR)hasbeenusedformicrostructuraIrefinementofthesteelsstudiedThemicrostructuresinthedifferentstates，mechanicalproperties，corrosion

3、andoxidationresistance，wearandcreepbehaviorsofthesiren【gthenedsteelspreparedhavebeensystematicallystudiedusingvarioustechniquesincludingopticalmicroscopy(oM)，scanningelectronmicroscopy(SEM)，thermogravimetricanalysis(TGA)

4、，transmissionelectronmicroscopy(TEM)，X—raydiffraction(XRD)MicrostructuralobservationsperformedonthesteelsstudiedshowthattheformationofTiCparticlesinsteelsdecreasesthesizeofmatrixgrainsinas—castmicrostructureandTiCparticl

5、eswithsizesrangingfrom01一10umdistributehomogenouslyandhaveafacetedmorphology、MththeformationofTiCthevolumefractionofferriteincreasesinthehypoeutectoidsteelcontaining0。55wt％Cwhiletheprecipitationofsecondarycementiteisinhi

6、bitedinthehypereutectoidsteelcontaining14wt％CinwhichslightsegregationofTiCparticleshasbeenobservedTestsofthemechanicalpropertiesofsteelsstudiedshowthattheadditionsofTiCimprovethestrengthofsteelsatbothroomandhightemperatu

7、res，whiletheelongationandtheimpactenergydecreaseThereductionoftensilestrengthobtainedfromthesteelcontainingO55wt％CwithTiCadditionwasduetotheformationofferritenetwork。ThestrengthofTiCstrengthened304steelsinroomtemperature

8、increasedwiththeincreaseoftheTiCadditonHoweverthestrengtheningeffectofTiCadditionisweakenedathightemperatureswiththeincreaseofTiCadditionWhentheingotsoftheTiCstrengthened2Crl3steelsisremeltedusingtheESRtechnique，TiCparti

9、clesisrefinedandthedistributionofparticlesbecomesmoreuniformTheelongationandtheimpactenergyofTiCstrengthened2Crl3isremarkablyimprovedafterESRprocessThefractureoftheTiCreinforced2Crl3steelprocessedbyinductionmeltingfurnac

10、eismainlycausedbythefailureofTiCparticleswhichhavethelargesizeandareununiformdistributionForthesteelsprocessedbyESR，crackingoftheparticlesisnoteasytooccurduetotherefinementofTiCparticlesandfractureofthesteelisbasicallyth

11、efailureofinterfacesbetweenparticlesandmatrixInthediluteHClsolutionthecorrosionrateof2Crl3steelrapidlyincreasedduetoTiCaddition，howeverthecorrosionrateofTiCstrengthened2Crl3steelwasobviouslyimprovedafterESRprocessTheoxid

12、ationrateof304steeldecreaseswithTiCaddition。buttheoxidationresistancesignificantlydecreasesifexcessiveTiCisaddedAtthetemperatureof850℃，severeintemaIoxidationisclearlyobservedin304steel，buthasnotappearinthesamplesofTiCstr

13、engthened304steels，inwhichiniercrystallineoxidationhasbeenfoundTheadditionofTiCparticleshastheeffectofimprovingtheoxidationresistanceofthesteelsCreeppropertiesofthe304steelattemperaturesbetween700℃and800“Candappliedstres

14、s55MPaaresignificantlyimprovedwithTiCadditionandhighercreepresistancehasbeenobtainedfromthesteelwithhigherTiCfraction111eimprovementoncreepresistanceof304steelwithTiCadditionismainlyattributedtothermalstabilityofTiCparti

15、cles，whichraisesthethresholdstressandthestabilityofsteelmicrostructureWearresistanceofcarbonsteelshasbeenimprovedwithTiCadditionunderoillubricant，but，theeffectofTiCadditiononweal“resistanceisweakenedwiththeincreasingoflo