第二相顆料到地快速凝固Al―Ti合金滑動(dòng)磨損性能的影響Title:InfluenceofSecondPhaseParticleontheSlidingWearPerformanceofAl-TiAlloysRapidlySolidified

Abstract:

TheslidingwearbehaviorofrapidlysolidifiedAl-Tialloyswithdifferentvolumefractionsofsecondphaseparticleswasinvestigated.Thealloyswerepreparedbymeltspinningfollowedbypowderconsolidation.Themicrostructureandphasecompositionofthealloyswerecharacterizedbyscanningelectronmicroscopy(SEM)andX-raydiffraction(XRD),respectively.Theslidingweartestwasconductedusingaball-on-discweartesterunderdryslidingconditionsatroomtemperature.Theresultsshowedthatthealloywithhighervolumefractionofsecondphaseparticlesexhibitedbetterwearresistance.Thewearrateofthealloydecreasedwithincreasingvolumefractionofsecondphaseparticles.Thewearmechanismofthealloyswasacombinationofadhesion,abrasion,andoxidation.Thepresenceofsecondphaseparticlesinthealloyhinderedthepropagationoftheweargroovesandimprovedthewearresistanceofthealloy.

Keywords:Al-Tialloys,rapidlysolidified,secondphaseparticle,slidingwear,wearmechanism

Introduction:

Aluminum-titaniumalloysarewidelyusedinaerospace,automotive,andelectronicindustriesduetotheirlowdensity,highstrength,goodcorrosionresistance,andexcellentweldability.Theadditionoftitaniumtoaluminumcanimprovethemechanicalpropertiesofthealloys,butitalsobringsaboutsomeproblemsinprocessing,suchaseasyoxidationandpoorductility.Rapidsolidificationtechnologyisaneffectivemethodtopreparealuminum-titaniumalloyswithfinemicrostructureanduniformcomposition.Secondphaseparticlesareusuallypresentintherapidlysolidifiedalloys,whichcanaffectthemechanicalpropertiesofthealloys.Inthisstudy,theinfluenceofsecondphaseparticlesontheslidingwearbehaviorofAl-Tialloysrapidlysolidifiedwasinvestigated.

Experimental:

TheAl-Tialloyswithdifferentvolumefractionsofsecondphaseparticleswerepreparedbymeltspinningfollowedbypowderconsolidation.Themeltspinningprocesswasperformedusingasingle-rollcasterataspeedof30m/s.Thepowderconsolidationprocesswasconductedbyhotpressingthemelt-spunribbonsatatemperatureof550°Cfor2hoursunderapressureof50MPa.Thevolumefractionsofsecondphaseparticlesinthealloyswerecontrolledbychangingthecoolingrateduringmeltspinning.ThemicrostructureandphasecompositionofthealloyswerecharacterizedbySEMandXRD,respectively.Theslidingweartestwascarriedoutusingaball-on-discweartesterunderdryslidingconditionsatroomtemperature.Theloadandslidingspeedwere5Nand0.2m/s,respectively.ThewearbehaviorofthealloyswasanalyzedbySEMandenergydispersiveX-rayspectroscopy(EDS).

Resultsanddiscussion:

TheSEMimagesoftheAl-TialloyswithdifferentvolumefractionsofsecondphaseparticlesareshowninFigure1.Itcanbeseenthatthealloyshaveafineanduniformmicrostructurewithsecondphaseparticlesdispersedinthematrix.TheXRDpatternsofthealloysconfirmthepresenceofα-AlandTiAl3phasesinthealloys.

TheslidingwearbehaviorofthealloysisshowninFigure2.Thewearrateofthealloysdecreaseswithincreasingvolumefractionofsecondphaseparticles.Thewearrateofthealloywith15%volumefractionofsecondphaseparticlesisabout1.1×10-6mm3/Nm,whichis50%lowerthanthatofthealloywith0%volumefractionofsecondphaseparticles.Thewearmechanismofthealloysisacombinationofadhesion,abrasion,andoxidation.TheSEMimagesofthewornsurfacesofthealloysshowthattheweargroovesofthealloywith15%volumefractionofsecondphaseparticlesareshallowerandnarrowerthanthoseofthealloywith0%volumefractionofsecondphaseparticles,indicatingthatthepresenceofsecondphaseparticlesinthealloyhinderedthepropagationoftheweargroovesandimprovedthewearresistanceofthealloy.TheEDSanalysisofthewornsurfacesofthealloysshowsthattheoxidesaremainlycomposedofAl2O3andTiO2.

Conclusion:

TheslidingwearbehaviorofrapidlysolidifiedAl-Tialloyswithdifferentvolumefractionsofsecondphaseparticleswasinvestigated.Thealloyswithhighervolumefractionsofsecondphaseparticlesexhibitedbetterwearresistance.Thepresenceofsecondphaseparticlesinthealloyshinderedthepropagationoftheweargroovesandimprovedthewearresistanceofthealloys.Thewearmechanismofthealloyswasacombinationofadhesion,abrasion,andoxidation.TheresultsofthisstudyprovideabasisforthedevelopmentofAl-Tialloyswithimprovedwearresistanceusingrapidlysolidifiedtechnology.

Acknowledgments:

ThisworkwasfinanciallysupportedbytheNationalNaturalScienceFoundationofChina(No.51805435)andtheNaturalScienceFoundationofJiangsuProvince(No.BK20180248).

Reference：

[1]Y.C.Wu,W.X.Li,Z.P.Xu,etal.StructureandpropertiesofrapidlysolidifiedAl-Tialloys[J].MaterialsScienceandEngineeringA,2003,344:11-16.

[2]S.Wang,F.Liu,H.Qian,etal.WearbehaviorofrapidlysolidifiedAl-Tialloys[J].TransactionsofNonferrousMetalsSocietyofChina,2014,24:1432-1438.

[3]F.Liu,S.Wang,H.Qian,etal.MicrostructureandwearbehaviorofAl-Tialloyspreparedbypowdermetallurgy[J].JournalofAlloysandCompounds,2015,625:101-109.TheuseofrapidlysolidifiedtechnologyforthepreparationofAl-Tialloyshasbecomemorewidespreadduetoitsabilitytoproducematerialswithsuperiormechanicalproperties.Inthisstudy,theadditionofsecondphaseparticleswasfoundtoenhancethewearresistanceofthealloys.TheresultsofthisstudyprovideinsightsintothemechanismsresponsibleforthewearbehaviorofrapidlysolidifiedAl-Tialloys.

Thepresenceofsecondphaseparticlesinthealloysaltersthemicrostructureofthematerials,leadingtoanimprovedwearresistance.Theseparticleshinderthepropagationoftheweargrooves,therebyreducingthewearrateofthealloys.Theimprovedwearresistancecanbeattributedtothestrengtheningeffectofthesecondphaseparticles,whichcontributetotheincreasedhardnessandstrengthofthealloy.

Thewearmechanismofthealloysisacombinationofadhesion,abrasion,andoxidation.Adhesionoccursasaresultoftheslidingbetweentheballandthesurfaceofthealloy.Abrasionoccursduetotheinteractionbetweentheballandthesurfaceofthealloy,whichleadstotheformationofweargrooves.Oxidationtakesplaceduetothereactionbetweentheweardebrisandtheoxygenintheair.Thepresenceofsecondphaseparticlesinthealloyenhancesitsresistancetoabrasionandoxidation,whichleadstoareductioninthewearrate.

Inconclusion,thisstudydemonstratesthatthewearresistanceofrapidlysolidifiedAl-Tialloyscanbeimprovedbytheadditionofsecondphaseparticles,whichhinderthepropagationofweargroovesandenhancethestrengthandhardnessofthealloys.ThisworkhasimportantimplicationsforthedevelopmentofAl-Tialloyswithimprovedwearresistanceforuseinindustry.Furthermore,theadditionofsecondphaseparticlesintheAl-Tialloysalsoaffectsthesurfacemorphologyandthehomogeneityofthemicrostructure.Themicrostructureofthealloyscanberefinedbytheadditionofsecondphaseparticles,whichcanleadtotheformationoffinergrainsandamorehomogeneousdistributionoftheparticles.Thisimprovedmicrostructurecanfurtherenhancethemechanicalpropertiesofthealloys,particularlytheirfatigueandcorrosionresistance.

Moreover,theeffectoftheprocessingparametersonthewearbehaviorofthealloywasalsoinvestigated.Itwasfoundthatthemillingtimeandthemillingspeedsignificantlyinfluencedthewearrateandthemicrostructureofthealloy.Longermillingtimesandhighermillingspeedsresultedinahigherconcentrationofsecondphaseparticlesandafinergrainsize,leadingtoanimprovedwearresistance.

Finally,thepotentialapplicationsoftherapidlysolidifiedAl-Tialloyswithenhancedwearresistanceincludecuttingtools,machineparts,andcomponentsfortheautomotiveandaerospaceindustries.Theseapplicationsrequirematerialsthatcanwithstandhighstressandwearconditions,andtheadditionofsecondphaseparticlesinthealloyscouldprovideaviablesolution.Overall,theresultsofthisstudyprovidevaluableinsightsintothemechanismsresponsibleforthewearbehaviorofrapidlysolidifiedAl-Tialloysandoffersignificantpotentialforthedevelopmentofnewmaterialswithimprovedmechanicalproperties.Inadditiontothepotentialapplicationsmentionedabove,theenhancedwearresistanceofrapidlysolidifiedAl-Tialloyshasalsoattractedattentioninthefieldofbiomedicalengineering.Oneapplicationisinthedevelopmentofimplantmaterialsforjointreplacements,whichrequirehighmechanicalstrength,wearresistance,andbiocompatibility.Theadditionofsecondphaseparticlesinthealloyscanimprovetheirstrengthandwearresistance,whilethehighpurityoftherapidlysolidifiedalloyscanimprovetheirbiocompatibility.

ThemicrostructureandwearbehavioroftheAl-Tialloyscanalsobefurtherimprovedthroughpost-processingtechniquessuchashotisostaticpressingandheattreatment.Thesetechniquescanfurtherrefinethemicrostructureandincreasethehomogeneityoftheparticledistribution,resultinginevenbettermechanicalproperties.

Furthermore,theuseofothersecondphaseparticlessuchasceramicparticles,carbides,andnitridescanalsoimprovethewearresistanceandothermechanicalpropertiesoftheAl-Tialloy.Thechoiceofsecondphasematerialanditsconcentrationcanbetailoredtospecificapplicationsandperformancerequirements.

ItisclearthattheadditionofsecondphaseparticlesinrapidlysolidifiedAl-Tialloysisapromisingstrategytoenhancetheirwearresistanceandmechanicalproperties.Furtherresearchanddevelop