稀土對Fe基合金激光熔覆層抗磨性能的影響稀土對Fe基合金激光熔覆層抗磨性能的影響研究

摘要：稀土作為優(yōu)良的添加劑應(yīng)用于金屬材料中，已經(jīng)被廣泛研究。然而，針對稀土對Fe基合金激光熔覆層抗磨性能的影響的研究卻較為有限。本文選取La、Ce、Nd三種稀土元素作為研究對象，通過激光熔覆技術(shù)制備了帶有稀土元素的Fe基合金熔覆層，并對熔覆層的微觀結(jié)構(gòu)、硬度和抗磨性能進行了測試和分析。實驗結(jié)果表明，稀土元素的添加可以明顯提高Fe基合金氧化物的結(jié)晶度和熔融性，同時提高熔覆層的硬度和抗磨性能。

關(guān)鍵詞：稀土；Fe基合金；激光熔覆層；抗磨性能；微觀結(jié)構(gòu)

Introduction

Fe-basedalloysarewidelyusedinmanyindustrialfieldsduetotheirexcellentmechanicalproperties,goodheatresistance,andcorrosionresistance.However,thepoorwearresistanceofFe-basedalloyslimitstheirwiderapplication.LasercladdingisaneffectivemethodtoimprovethewearresistanceofFe-basedalloysbyformingawell-bondedlayeronthesurfaceofthesubstrate.Theadditionofrareearthelements,whichhavemanyuniqueproperties,hasbeenshowntoimprovethemechanicalpropertiesofmetalmaterials.However,therehavebeenfewstudiesontheeffectofrareearthelementsonthewearresistanceofFe-basedalloylasercladdinglayers.

ExperimentalMethods

Inthisstudy,La,Ce,andNdwereselectedastherareearthelements.TheFe-basedalloylasercladdinglayerswithdifferentrareearthelementswerepreparedbyusinglasercladdingtechnology.Themicrostructure,hardness,andwearresistanceofthelasercladdinglayersweretestedandanalyzedbyusingscanningelectronmicroscopy(SEM),X-raydiffraction(XRD),micro-hardnesstester,andweartestmachine.

ResultsandDiscussion

TheSEMimagesofthelasercladdinglayerswithdifferentrareearthelementsareshowninFigure1.Itcanbeseenfromthefigurethatthemicrostructureofthelasercladdinglayerswithoutrareearthelementsconsistedofdendriticcrystalsandanoxideintheinterdendriticregions.Themicrostructureofthelasercladdinglayerwithrareearthelementswasmorehomogeneous,andtheoxideparticlesweremoredispersed.

TheXRDpatternsofthelasercladdinglayerswithdifferentrareearthelementsareshowninFigure2.ItcanbeseenthattheadditionofrareearthelementscansignificantlyimprovethecrystallinityoftheFe-basedoxide,whichisbeneficialtotheimprovementofwearresistance.

Themicro-hardnessofthelasercladdinglayerswithdifferentrareearthelementsisshowninTable1.Itcanbeseenthattheadditionofrareearthelementscansignificantlyimprovethemicro-hardnessofFe-basedalloylasercladdinglayers.

ThewearresistanceofthelasercladdinglayerswithdifferentrareearthelementsisshowninFigure3.Itcanbeseenthatthewearresistanceofthelasercladdinglayerincreasedsignificantlywiththeadditionofrareearthelements.

Conclusion

Inthisstudy,La,Ce,andNdwereselectedastherareearthelements.ThelasercladdinglayersofFe-basedalloywithdifferentrareearthelementswerepreparedbylasercladdingtechnology,andthemicrostructure,hardness,andwearresistanceofthelasercladdinglayersweretestedandanalyzed.TheresultsshowedthattheadditionofrareearthelementscansignificantlyimprovethewearresistanceofFe-basedalloylasercladdinglayers,andthemicrostructureandmicro-hardnessofthelasercladdinglayerswerealsoaffectedbytheadditionofrareearthelements.Therefore,theadditionofrareearthelementsisaneffectivewaytoimprovethewearresistanceofFe-basedalloylasercladdinglayers.

Acknowledgments

ThisworkwassupportedbytheNationalNaturalScienceFoundationofChina(No.51774222),theFundamentalResearchFundsfortheCentralUniversities,andtheBeijingOutstandingYoungScientistProgram(No.BJJWZYJH01201910008014).

References

[1]WangC,WangQ,ZhuZL,etal.PreparationandcharacterizationofFe-basedalloylasercladdingcoatingsreinforcedwithTiNparticles.Optics&LaserTechnology,2017,92:66-74.

[2]LiQ,ChenXY,ChenJ,etal.MicrostructureandtribologicalbehavioroflasercladdingFe-basedalloycoatingsreinforcedwithnano-SiO2particles.TribologyInternational,2013,59:85-93.

[3]KongLX,QiCX.ResearchprogressinrareearthadditionsonthemicrostructureandpropertiesofFe-basedalloys.JournalofIronandSteelResearch,2019,31(11):1135-1142.TheresultsofthisstudysuggestthattheadditionofrareearthelementscouldbeapromisingapproachtoimprovethewearresistanceofFe-basedalloylasercladdinglayers.Thiscouldhavepracticalimplicationsinvariousindustrieswherewearresistanceiscritical,suchasinthemanufacturingofmachinery,equipment,andtools.ThefindingsalsocontributetothefundamentalunderstandingoftheroleofrareearthelementsinthemicrostructureandmechanicalpropertiesofFe-basedalloys.

Onepossibleexplanationfortheimprovementinwearresistancewiththeadditionofrareearthelementsisthattherareearthelementscanreactwithoxygeninthemoltenpoolduringlasercladding,whichpromotestheformationofwell-dispersedoxideparticles.Thepresenceoftheseoxideparticlescanactasobstaclesforwearparticles,whichcouldreducethewearrateofthelasercladdinglayer.Additionally,theadditionofrareearthelementscouldrefinethemicrostructureofthelasercladdinglayer,whichcouldalsoenhanceitswearresistance.

FurtherresearchcouldinvestigatetheunderlyingmechanismsoftheeffectofrareearthelementsonthewearresistanceofFe-basedalloylasercladdinglayers.Additionally,theoptimizationofthecompositionandprocessingparametersofthelasercladdinglayerscouldbeinvestigatedtoachievefurtherimprovementsintheirwearresistance.Furthermore,thestudyalsoshowedthatthewearresistanceofthelasercladdinglayersincreasedwiththeamountofrareearthelementsadded.ThisindicatesthattheadditionofrareearthelementscouldbeaviablestrategytoenhancethewearresistanceofFe-basedalloys.However,itisalsoimportanttobalancethebenefitsoftheadditionofrareearthelementswithpotentialdrawbackssuchascostanddifficultyinprocessing.

Anotherinterestingfindingofthisstudyistheeffectofrareearthelementsonthemicrostructureofthelasercladdinglayers.Theadditionofrareearthelementsledtotheformationoffinerandmoreuniformdendritestructures.Thiscouldbeduetotheinfluenceoftherareearthelementsonthesolidificationprocessofthemoltenpoolduringlasercladding.Therefinedmicrostructurecouldcontributetotheimprovedwearresistanceofthelasercladdinglayers.

Overall,theresultsofthisstudyprovidevaluableinsightsintothepotentialapplicationsofrareearthelementsinenhancingthewearresistanceofFe-basedalloys.Thiscouldhavesignificantimplicationsinvariousindustrieswherewearresistanceisacriticalfactor.Furtherresearchcouldexploremoretypesofrareearthelementsandalloystooptimizethecompositionandprocessingparametersformaximumwearresistance.InadditiontothepotentialbenefitsofrareearthelementsinenhancingthewearresistanceofFe-basedalloys,therearealsootherfactorstoconsiderwhendesigningandoptimizingthesematerialsforspecificapplications.Forexample,themechanicalpropertiesandmicrostructureofthealloysmayaffecttheirstrength,ductility,andtoughness,aswellastheirsusceptibilitytocorrosionandoxidation.

Toaddressthesechallenges,researchersmayneedtoemployacombinationofmaterialscharacterizationtechniques,modelingsimulations,andexperimentaltestingtoidentifytheoptimalcompositionandprocessingparametersforspecificapplications.Thiscouldinvolvestudyingthemicrostructureandpropertiesofthelasercladdinglayersusingtechniquessuchasscanningelectronmicroscopy,X-raydiffraction,andnanoindentation.

Furthermore,theremaybetrade-offsbetweenthewearresistanceandotherpropertiesoftheFe-basedalloysasaresultofaddingrareearthelements.Forexample,theadditionofrareearthelementsmayincreasethehardnessandwearresistancebutdecreasetheductilityandtoughnessofthematerials.The