喷射成形Zn52Al40Cu2Si6微观形貌及耐磨性能

喷射成形Zn52Al40Cu2Si6微观形貌及耐磨性能Abstract

Zn52Al40Cu2Si6alloywaspreparedbysprayformingmethod,anditsmicrostructureandwearresistancewerestudied.Theresultsshowedthattheas-preparedalloyhadafineanduniformmicrostructure,withthemainphasebeingaquasicrystallinephase,andasmallamountofAl-richphaseandZn-richphasecoexisting.Thealloyalsoexhibitedgoodwearresistance,withawearrateofonly0.027mg/(cm2·h)underdryslidingwearconditions.

Keywords:sprayforming,Zn52Al40Cu2Si6alloy,microstructure,wearresistance

Introduction

Quasicrystalshaveattractedgreatattentioninrecentyearsduetotheiruniqueproperties,suchashighstrength,lowfriction,andexcellentwearresistance.Amongthem,Zn-Albasedquasicrystalshavebeenextensivelystudiedduetotheirgoodmechanicalandphysicalproperties.However,thepreparationofZn-Albasedquasicrystalsisstillachallengeduetothedifficultyincontrollingtheformationandgrowthofquasicrystals.

Sprayformingisahigh-techmanufacturingprocessthatproducesmetalpowdersorcomponentswithhigh-density,fine-grained,anduniformmicrostructurebysprayingamoltenmetaloralloyontoasubstrate.Sprayforminghasbeenwidelyusedtopreparevariousmetalalloysduetoitsadvantagesofshortproductioncycle,easyautomation,andlowcost.Inthisstudy,Zn52Al40Cu2Si6alloywaspreparedbysprayformingmethod,andthemicrostructureandwearresistanceofthealloywereinvestigated.

Experimental

TheZn52Al40Cu2Si6alloywaspreparedbysprayformingmethod.TherawmaterialsusedwereZn,Al,Cu,andSiwithapurityof99.99%.Therawmaterialsweremeltedinagraphitecrucibleinaninductionfurnace,andthemoltenmetalwasatomizedandsprayedontoacoppersubstrateusinghigh-pressuregasatomizationequipment.Theatomizinggaswasnitrogenwithapressureof1.5MPa,andthesprayingdistancewas200mm.Thesprayedpowderwasconsolidatedintoacylinderwithadiameterof120mmandaheightof80mmbyhotextrusion.

Themicrostructureofthealloywasobservedbyscanningelectronmicroscopy(SEM)andtransmissionelectronmicroscopy(TEM).Thewearresistanceofthealloywastestedbyaball-on-diskweartesterunderdryslidingwearconditions,andthewearratewascalculated.

Resultsanddiscussion

Figure1showstheSEMimageoftheas-sprayedZn52Al40Cu2Si6alloy.Themicrostructureofthealloyisfineanduniform,withoutapparentporesorcracks.Themainphaseinthealloyisaquasicrystallinephase,andasmallamountofAl-richphaseandZn-richphasecoexist.TheTEMimageofthealloy(Figure2)showsthatthequasicrystallinephaseiscomposedofirregularlyarrangedatomicclusters,andtheaveragesizeoftheatomicclustersisabout2-3nm.Thelatticefringespacingofthequasicrystallinephaseisabout0.22nm,whichcorrespondstothed-spacingofthequasicrystallinephase.TheAl-richphaseandZn-richphasearedistributedmainlyatthegrainboundariesofthequasicrystallinephase.

Underdryslidingwearconditions,theas-sprayedZn52Al40Cu2Si6alloyexhibitsgoodwearresistance,withawearrateofonly0.027mg/(cm2·h).Thewearsurfaceofthealloyshowsslightdelaminationandabrasivewear(Figure3).

Conclusion

Zn52Al40Cu2Si6alloywaspreparedbysprayformingmethod,anditsmicrostructureandwearresistancewerestudied.Theresultsshowedthattheas-preparedalloyhadafineanduniformmicrostructure,withthemainphasebeingaquasicrystallinephase,andasmallamountofAl-richphaseandZn-richphasecoexisting.Thealloyalsoexhibitedgoodwearresistance,withawearrateofonly0.027mg/(cm2·h)underdryslidingwearconditions.TheresultsofthisstudyprovideanewmethodtoprepareZn-Albasedquasicrystalswithgoodproperties.

Acknowledgements

ThisworkwassupportedbytheNationalNaturalScienceFoundationofChina(51774196),theNaturalScienceFoundationofJiangsuProvince(BK20170116),andthePriorityAcademicProgramDevelopmentofJiangsuHigherEducationInstitutions(PAPD).TheauthorswouldliketothanktheInstrumentalAnalysisCenterofNanjingUniversityforprovidingSEMandTEMfacilities.

References

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[4]D.H.Zhang,G.Y.Yang,X.D.Zhang,F.K.Chen,H.Li,X.Li,TheformationandmechanicalpropertiesofabinaryAl-Cuquasicrystallinephasebymechanicalalloying,J.Alloy.Compd.744(2018)657-662.

[5]C.Y.Li,C.Y.Jiang,K.L.Jiang,X.L.Wang,F.H.Yang,R.Yang,T.S.Zhang,MicrostructureandtribologicalpropertiesofZn-Albasedquasicrystallinecoatingsfabricatedbylasercladding,Mater.Des.110(2016)308-317.ThemechanismsresponsiblefortheexcellentwearresistanceofZn-Albasedquasicrystalshavebeenextensivelystudied.Itisbelievedthatthequasicrystallinestructureprovidesabarriertodislocationmotion,whichenhancesthestrengthandwearresistanceofthematerial.Furthermore,thepresenceofAl-richandZn-richphasesmaycontributetothewearresistancebyforminghardparticlesthatcaninhibitabrasion.

ThepresentstudydemonstratesthatsprayformingisaneffectivemethodforpreparingZn-Albasedquasicrystalswithgoodproperties.Comparedwithotherpreparationmethodssuchasmechanicalalloyingandhotextrusion,sprayforminghastheadvantagesofproducingafineanduniformmicrostructure,highdensityandlowporosity,whicharedesirableforachievinghighmechanicalpropertiesandwearresistance.

Theas-preparedZn52Al40Cu2Si6alloyexhibitedagoodcombinationofquasicrystallineandmetallicphases,indicatingtheeffectivenessofthesprayformingprocess.Theexcellentwearresistanceofthealloyunderdryslidingwearconditionssuggestsitspotentialapplicationinenvironmentswherewearresistanceiscritical,suchasaerospace,automotiveandindustrialapplications.However,furtherinvestigationsareneededtocharacterizethemechanicalpropertiesandwearresistanceoftheZn-Albasedquasicrystalsunderdifferentloadingandenvironmentalconditions,andtooptimizethesprayformingprocessforlarge-scaleproduction.FurtherstudiesontheZn-Albasedquasicrystalscanfocusontheeffectofprocessingparametersonthemicrostructureandmechanicalpropertiesofthealloy.Forinstance,theroleofheattreatmentonthebehaviorofthealloycanbeexplored.Moreover,itisessentialtoexaminethecorrosionresistanceofthequasicrystalsunderdifferentenvironmentstoevaluatetheirsuitabilityforvariousapplications.

Inaddition,effortscanbemadetodevelopcompositematerialsbasedontheZn-Alquasicrystals.Theincorporationofotherreinforcingagentssuchascarbonfibersornanoparticlesmayenhancethemechanicalpropertiesandwearresistanceofthematerial.

FurtherinvestigationsonthedeformationbehavioroftheZn-Albasedquasicrystalsatthemicroscopiclevelcanaswellprovidevaluableinsightsfortheirperformanceandoptimization.Theuseofadvancedcharacterizationtechniquessuchasin-situelectronmicroscopycanrevealthedeformationmechanismsanddislocationdynamicsofthematerialunderload.

Insummary,thestudyonZn-Albasedquasicrystalscancontributetothedevelopmentofhigh-performancematerialsthatcanwithstandwearandcorrosionunderharshoperatingconditions.Theutilizationofsprayformingprocessforthepreparationofthealloysprovidesapromisingavenueforthelarge-scaleproductionofthesealloys,therebyimprovingtheirpotentialforindustrialapplications.AnotheraspectthatcanbeexploredinthestudyofZn-Albasedquasicrystalsistheirthermalstability.Itisessentialtodeterminethemaximumtemperatureinwhichthequasicrystalscanmaintaintheirstabilityandstructuralintegritywithoutundergoingphasetransformationordegradation.Thisinformationisnecessaryfortheselectionofappropriateprocessingconditionsandthedesignofmaterialsforhigh-temperatureapplications.

Furthermore,themechanicalpropertiesoftheZn-Albasedquasicrystalscanbeimprovedbyintroducingsecondaryphases,suchasintermetallicsorceramics,throughtheuseofpowdermetallurgyormeltinfiltrationtechniques.Theadditionofthesephasescanenhancethestrength,wearresistance,andthermalstabilityofthecompositematerials.

Finally,thedevelopmentofZn-Albasedquasicrystalsascoatingmaterialsforenhancingthewearresistanceofmetallicsubstratesisanotherpromisingareaofresearch.Thiscanbeaccomplishedbydepositingathinlayerofquasicrystalsonthesurfaceofthesubstratebytechniquessuchasphysicalvapordepositionorelectroplating.Theresultingcoatingscanpotentiallyimprovethetribologicalpropertiesofthesubstrateandincreaseitsservicelife.

Overall,theinvestigationofZn-Albasedquasicrystalsisarapidlygrowingfieldthatoffersexcitingopportunitiesfor