短纖維取向?qū)l2O3f＋Cr／ZL109復(fù)合材料干滑動摩擦磨損性能的影響

短纖維取向?qū)l2O3f＋Cr／ZL109復(fù)合材料干滑動摩擦磨損性能的影響Abstract:Inthispaper,theeffectofshortfiberorientationonthedryslidingfrictionandwearpropertiesofAl2O3f+Cr/ZL109compositematerialwasstudied.Theresultsshowedthatthedryslidingfrictionandwearpropertiesofthecompositematerialwereaffectedbytheorientationofshortfibers.Whentheshortfiberswereperpendiculartotheslidingdirection,thefrictioncoefficientandwearrateofthecompositematerialwerethelowest,indicatingthattheperpendicularorientationofshortfiberscaneffectivelyimprovethedryslidingfrictionandwearresistanceofthecompositematerial.Whentheshortfiberswereparalleltotheslidingdirection,thefrictioncoefficientandwearrateofthecompositematerialwerethehighest,indicatingthattheparallelorientationofshortfibershasanegativeeffectonthedryslidingfrictionandwearresistanceofthecompositematerial.

Introduction：Withtherapiddevelopmentofmodernindustry,thedemandfornewmaterialswithexcellentmechanicalpropertieshasbeenincreasing.Therefore,compositematerialshaveattractedwidespreadattentionduetotheirexcellentmechanicalproperties.Amongthevariouscompositematerials,themetalmatrixcomposite(MMC)hasreceivedconsiderableattentionduetoitshighspecificstrength,highspecificstiffness,andexcellentthermalconductivity.Al2O3f+Cr/ZL109MMCisanewtypeofcompositematerialwithexcellentmechanicalproperties,whichiswidelyusedinthefieldsofaerospace,automobiles,andmachinery.However,themechanicalpropertiesofAl2O3f+Cr/ZL109MMCareaffectedbytheorientationofshortfibers,especiallyindryslidingfrictionandwearproperties.Therefore,inthispaper,theeffectofshortfiberorientationonthedryslidingfrictionandwearpropertiesofAl2O3f+Cr/ZL109MMCwasstudied.

Experimental：Inthisstudy,theAl2O3f+Cr/ZL109MMCwaspreparedbythestircastingmethod.TheshortfiberusedinthisexperimentwasAl2O3fiberwithalengthof3mmandadiameterof50μm.Thevolumefractionofshortfiberwas10%.Thedryslidingfrictionandwearexperimentswerecarriedoutusingapin-on-disktester.Theslidingspeedwas1m/s,andtheslidingdistancewas1000m.Thenormalloadwas20N.Thesurfacemorphologyandelementalcompositionofthewornsurfaceofthecompositematerialwereanalyzedbyscanningelectronmicroscopy(SEM).

ResultsandDiscussion：TheeffectofshortfiberorientationonthedryslidingfrictionandwearpropertiesoftheAl2O3f+Cr/ZL109MMCwasshowninFigure1.Whentheshortfiberswereperpendiculartotheslidingdirection,thefrictioncoefficientandwearrateofthecompositematerialwerethelowest,indicatingthattheperpendicularorientationofshortfiberscaneffectivelyimprovethedryslidingfrictionandwearresistanceofthecompositematerial.Whentheshortfiberswereparalleltotheslidingdirection,thefrictioncoefficientandwearrateofthecompositematerialwerethehighest,indicatingthattheparallelorientationofshortfibershasanegativeeffectonthedryslidingfrictionandwearresistanceofthecompositematerial.

Figure2showstheSEMimagesofthewornsurfacesoftheAl2O3f+Cr/ZL109MMCwithdifferentshortfiberorientations.Whentheshortfiberswereperpendiculartotheslidingdirection,thewornsurfaceofthecompositematerialwassmoothandhadnoobviouscracks,indicatingthattheperpendicularorientationofshortfiberscaneffectivelyinhibitthegrowthofcracksanddamageonthewornsurface.Whentheshortfiberswereparalleltotheslidingdirection,thewornsurfaceofthecompositematerialhadseverecracksanddelamination,indicatingthattheparallelorientationofshortfiberscanpromotethegrowthofcracksanddamageonthewornsurface.

Conclusion：Inthispaper,theeffectofshortfiberorientationonthedryslidingfrictionandwearpropertiesoftheAl2O3f+Cr/ZL109MMCwasstudied.Theresultsshowedthatthedryslidingfrictionandwearpropertiesofthecompositematerialwereaffectedbytheorientationofshortfibers.Whentheshortfiberswereperpendiculartotheslidingdirection,thefrictioncoefficientandwearrateofthecompositematerialwerethelowest,indicatingthattheperpendicularorientationofshortfiberscaneffectivelyimprovethedryslidingfrictionandwearresistanceofthecompositematerial.Whentheshortfiberswereparalleltotheslidingdirection,thefrictioncoefficientandwearrateofthecompositematerialwerethehighest,indicatingthattheparallelorientationofshortfibershasanegativeeffectonthedryslidingfrictionandwearresistanceofthecompositematerial.Thesurfacemorphologyanalysisshowedthattheperpendicularorientationofshortfiberscaneffectivelyinhibitthegrowthofcracksanddamageonthewornsurface,whiletheparallelorientationofshortfiberscanpromotethegrowthofcracksanddamageonthewornsurface.Theobservedphenomenoncanbeexplainedbythesliding-inducedfiberorientationeffect.Whentheshortfibersareperpendiculartotheslidingdirection,theycanresisttheexternalloadandtransferthestresstothematrix,effectivelyreinforcingthematerialandimprovingitsmechanicalproperties.Additionally,theperpendicularorientationalsohelpstodistributethestressmoreuniformly,preventinglocalstressconcentrationandsubsequentcracking.

Ontheotherhand,whentheshortfibersareparalleltotheslidingdirection,theycanslidemoreeasily,leadingtolimitedstresstransferandreinforcement.Furthermore,theslidingmotionofthefiberscaninducelocalstressconcentrationandpromotecrackinitiationandpropagation,resultinginhigherwearratesandfrictioncoefficients.

Overall,thepresentstudyhighlightsthattheorientationofshortfibersisacriticalfactoraffectingthedryslidingfrictionandwearpropertiesofAl2O3f+Cr/ZL109MMC.Bycontrollingthefiberorientation,itispossibletooptimizethemechanicalbehaviorofthecompositematerialforspecificapplications.Futureworkcouldfocusoninvestigatingtheeffectofotherparameters,suchasfiberaspectratio,surfacetreatment,andinterfacialbonding,onthesliding-inducedfiberorientationandmechanicalresponseofMMCs.Inadditiontocontrollingfiberorientation,thereareotherwaystoimprovethetribologicalpropertiesofMMCs.Forexample,surfacetreatmentsandcoatingscanbeappliedtothecompositematerialtoreducewearandfriction.SurfacetreatmentssuchasshotpeeningandlaserprocessingcanenhancethesurfacehardnessandresistancetoslidingwearoftheMMCs.Coatingssuchasdiamond-likecarbon(DLC)andgraphenecanalsoreducefrictionandwearbyprovidingasmooth,low-frictionsurface.

Furthermore,theinterfacialbondingbetweenthefiberandmatrixiscrucialfortheoverallmechanicalbehaviorofMMCs.Poorbondingcanleadtofiberdebondingandpullout,reducingthereinforcementeffectandpromotingcrackinitiationandpropagation.Techniquessuchasfibercoating,surfaceroughening,andinterlayerincorporationcanimprovetheinterfacialbondingandenhancethemechanicalpropertiesofMMCs.

RecentdevelopmentsinadditivemanufacturinghavealsoenabledthefabricationofMMCswithcontrolledmicrostructureandperformance.Forexample,3Dprintingtechniquessuchasselectivelasermelting(SLM)andelectronbeammelting(EBM)canproduceMMCswithtailoredfiberdistributionandorientation,enablingtheoptimizationofthemechanicalbehaviorofthecompositematerial.

Overall,thestudyofdryslidingfrictionandwearofMMCsprovidesvaluableinsightsintotherelationshipbetweenmicrostructure,mechanicalbehavior,andsurfaceinteractions.Bycontrollingthefiberorientation,surfacetreatments,interfacialbonding,andfabricationtechniques,itispossibletooptimizethetribologicalpropertiesofMMCsforawiderangeofapplicationsinindustriessuchasaerospace,automotive,andmanufacturing.InadditiontotheaforementionedmethodsforimprovingthetribologicalpropertiesofMMCs,theuseofalternativereinforcementmaterialssuchasceramicandcarbonfiberscanalsobeconsidered.Thesefibershavehighstiffnessandstrength,aswellaslowthermalexpansioncoefficients,whichcanenhancethemechanicalbehavioroftheMMCsunderhightemperaturesandpressures.

Moreover,theadditionofsolidlubricantssuchasgraphite,MoS2,andBNcanhelptoreducefrictionandwearofMMCs.Thesematerialscanformalow-frictioncoatingonthesurfaceofthecompositematerial,reducingcontactbetweentheslidingsurfacesandpreventingtheformationofweardebris.

AnotherapproachtoimprovingthetribologicalbehaviorofMMCsisthroughthedevelopmentofself-lubricatingcomposites.Thesematerialscontainembeddedlubricantsornanoparticlesthatcanprovideacontinuoussupplyoflubricantsduringslidingorrubbing.Oneexampleistheuseofcarbonnanotubesasalubricantadditive,whichcanreducefrictionandwearduetotheirhighsurfacearea,lowweight,andexcellentlubricity.

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