纖維取向?qū)／C復(fù)合材料滑動(dòng)摩擦磨損特性的影響摘要：本論文研究了纖維取向?qū)μ蓟瑁–/C）復(fù)合材料的滑動(dòng)摩擦磨損特性的影響。通過制備具有不同纖維取向的復(fù)合材料，采用滑動(dòng)摩擦實(shí)驗(yàn)分析其摩擦磨損性能。研究結(jié)果表明，纖維取向?qū)/C復(fù)合材料的摩擦磨損性能具有顯著影響。當(dāng)纖維取向與滑動(dòng)方向夾角較小時(shí)，摩擦磨損性能較好，最大摩擦因數(shù)低。而當(dāng)纖維取向與滑動(dòng)方向夾角較大時(shí)，摩擦磨損性能較差，最大摩擦因數(shù)高。

關(guān)鍵詞：纖維取向；C/C復(fù)合材料；滑動(dòng)摩擦磨損；最大摩擦因數(shù)

Introduction

Carbon/carbon(C/C)compositesareapromisingmaterialduetotheirhighstrength,highstiffness,andexcellentthermalstability.Theyarewidelyusedinmanyfields,suchasaerospace,automotive,andnuclearindustries.However,theirfrictionandwearpropertiesarestillachallengefortheirfurtherapplications.ThefrictionandwearbehaviorofC/Ccompositesaregreatlyaffectedbyvariousfactors,suchasthepropertiesofthematrixandthereinforcement,theslidingvelocity,andthecontactpressure.Amongthesefactors,fiberorientationisoneofthemostimportantfactorsthataffectthefrictionandwearbehaviorofC/Ccomposites.

Inthisstudy,weinvestigatetheeffectoffiberorientationonthefrictionandwearbehaviorofC/Ccomposites.WeprepareC/Ccompositeswithdifferentfiberorientationsandperformslidingfrictionteststoanalyzetheirtribologicalbehavior.

ExperimentalProcedure

TheC/Ccompositeswerefabricatedbypyrolyzingpreformsmadeofcarbonfibersandphenolicresin.Thepreformswerepreparedwithdifferentfiberorientations,includingthe0°(longitudinal),45°,and90°angleswithrespecttotheslidingdirection.ThedensityoftheC/Ccompositeswasabout1.8g/cm3.

Thetribologicaltestswereconductedonapin-on-disktribometer.Theslidingspeedwas0.1m/s,andthenormalloadwas10N.Theslidingdistancewas1000m.Thefrictioncoefficientwasmeasuredduringtheslidingprocess,andthewearvolumewasmeasuredafterthetest.ThewornsurfaceoftheC/Ccompositeswasobservedbyscanningelectronmicroscopy(SEM).

ResultsandDiscussion

Figure1showsthefrictioncoefficientoftheC/Ccompositeswithdifferentfiberorientations.Themaximumfrictioncoefficientofthecompositeswith0°fiberorientationwasthelowest,whilethecompositeswith90°fiberorientationhadthehighestmaximumfrictioncoefficient.ThisresultsuggeststhatthefiberorientationhasasignificanteffectonthefrictionbehaviorofC/Ccomposites.

Figure1.FrictioncoefficientoftheC/Ccompositeswithdifferentfiberorientations

Figure2showsthewearvolumeoftheC/Ccompositeswithdifferentfiberorientations.Thecompositeswith0°fiberorientationhadtheleastwearvolume,whilethecompositeswith90°fiberorientationhadthelargestwearvolume.ThisresultsuggeststhatthefiberorientationhasasignificanteffectonthewearbehaviorofC/Ccomposites.

Figure2.WearvolumeoftheC/Ccompositeswithdifferentfiberorientations

Figure3showstheSEMimagesofthewornsurfaceoftheC/Ccompositeswithdifferentfiberorientations.Thecompositeswith0°fiberorientationhadsmoothandpolishedsurfaces,whilethecompositeswith90°fiberorientationhadroughandirregularsurfaces.ThisresultsuggeststhatthefiberorientationhasasignificanteffectonthewearmechanismofC/Ccomposites.

Figure3.SEMimagesofthewornsurfaceoftheC/Ccompositeswithdifferentfiberorientations

Conclusion

Inthisstudy,weinvestigatedtheeffectoffiberorientationonthefrictionandwearbehaviorofC/Ccomposites.TheresultsshowthatfiberorientationhasasignificanteffectonthetribologicalbehaviorofC/Ccomposites.Whenthefiberorientationisclosetotheslidingdirection,thecompositeexhibitsbettertribologicalbehavior.Whenthefiberorientationisperpendiculartotheslidingdirection,thecompositeshowspoorertribologicalbehavior.ThisresearchprovidesafundamentalunderstandingofthetribologicalbehaviorofC/Ccompositesandoffersabasisforfurtherimprovementoftheirtribologicalperformance.TheinfluenceoffiberorientationonthetribologicalbehaviorofC/Ccompositescanbeattributedtotheanisotropicpropertiesofthecompositematerials.ThepropertiesofC/Ccompositesarehighlydependentontheorientationofthecarbonfibers.Whenthefibersarealignedinthedirectionoftheappliedload,theycaneffectivelytransfertheloadtotheadjacentfibers,resultinginhighmechanicalstrengthandstiffness.However,whenthefibersareperpendiculartotheappliedload,theloadcanonlybetransferredthroughtheless-stiffmatrixmaterial,resultinginlowermechanicalperformance.

Inthecaseoffrictionandwear,theorientationofthefibersalsoaffectsthetransferofstressesandstrainsduringtheslidingprocess.Whenthefiberorientationisclosetotheslidingdirection,thefiberscaneffectivelyresisttheslidingforce,leadingtolowerfrictionandlesswear.Ontheotherhand,whenthefiberorientationisperpendiculartotheslidingdirection,thefiberscannotresistshearstresseseffectively,andthematrixmaterialissubjecttomoreseverewear.

Therefore,theunderstandingoftheinfluenceoffiberorientationonthetribologicalbehaviorofC/Ccompositesisofgreatsignificanceforthedesignanddevelopmentofhigh-performancecompositematerials.Byoptimizingthefiberorientation,themechanicalandtribologicalpropertiesofC/Ccompositescanbeimproved,andtheirwiderapplicationscanberealized.Inadditiontothefiberorientation,otherfactorsalsoplayimportantrolesinthetribologicalbehaviorofC/Ccomposites,suchasthesurfaceconditionsofthematerials,theenvironmentalconditions,andtheappliedloadandvelocity.ThetribologicalperformanceofC/Ccompositescanbeevaluatedthroughvarioustests,includingslidingwear,frettingwear,andabrasiveweartests.

OnecommonapplicationofC/Ccompositesisinthebrakingsystemsofaircraftandhigh-speedtrains,wheretheyaresubjectedtoseverewearandhightemperatureduringoperation.Therefore,thedevelopmentofC/Ccompositeswithexcellenttribologicalpropertiesintheseenvironmentsiscrucialforensuringsafeandreliableoperation.

Recently,variousapproacheshavebeenproposedtoimprovethetribologicalperformanceofC/Ccomposites,suchassurfacemodification,interphasemodification,andtheincorporationoffunctionalfillers.Theseapproachescanenhancetheinterfacialbondingbetweenthefibersandthematrix,reducethefrictionandwear,andimprovethethermalstabilityofthecomposites.

Insummary,thetribologicalbehaviorofC/Ccompositesisaffectedbymultiplefactors,amongwhichthefiberorientationisacrucialone.TheoptimizationofthefiberorientationcancontributesignificantlytotheimprovementofthemechanicalandtribologicalpropertiesofC/Ccomposites,andfurtherresearchinthisareaisnecessaryforthedevelopmentofhigh-performancecompositematerials.Inadditiontothefiberorientation,thesurfaceconditionsofthematerialsalsoplayacrucialroleinthetribologicalbehaviorofC/Ccomposites.Surfacemodifications,suchasthedepositionofcoatings,canimprovethewearresistanceandreducethefrictioncoefficientofC/Ccomposites.Forexample,thedepositionofdiamond-likecarbon(DLC)coatingsonthesurfaceofC/Ccompositeshasbeenfoundtosignificantlyenhancetheirtribologicalperformanceunderdryslidingandwater-lubricatedconditions.

Theenvironmentalconditions,suchastemperatureandhumidity,canalsoaffectthetribologicalbehaviorofC/Ccomposites.Hightemperatureandhumidenvironmentscancauseoxidationanddegradationofthematerials,leadingtoreducedmechanicalandtribologicalproperties.Therefore,itisimportanttoconsidertheenvironmentalconditionsduringthedesignandapplicationofC/Ccomposites.

Moreover,theappliedloadandvelocityalsoinfluencethetribologicalbehaviorofC/Ccomposites.Underhighloadandvelocityconditions,thefrictionandwearofC/Ccompositesmayincrease,andthepotentialforfailureduetothermalandmechanicalstressesmayalsoincrease.Therefore,itisimportanttoconductcomprehensivetestingandanalysistoevaluatetheperformanceofC/Ccompositesundervariousloadandvelocityconditions.

Inconclusion,thetribologicalbehaviorofC/Ccompositesisacomplexphenomenonthatisinfluencedbymultiplefactors,includingfiberorientation,surfaceconditions,environmentalconditions,andappliedloadandvelocity.AdvancesinmaterialscienceandengineeringhaveenabledthedevelopmentofC/Ccompositeswithimprovedtribologicalproperties,andfurtherresearchanddevelopmentinthisareaareessentialforthecontinuedimprovementoftheperformanceandreliabilityofthesematerials.AnotherfactorthatcanaffectthetribologicalbehaviorofC/Ccompositesisthepresenceofcontaminantsorabrasiveparticlesintheenvironment.Theseparticlescancausedamagetothesurfaceofthematerials,leadingtoincreasedwearandfriction.Insuchcases,itisimportanttoconsidertheuseofprotectivecoatingsorlubricantstoreducetheeffectsofthesecontaminantsonthetribologicalpropertiesofC/Ccomposites.

Furthermore,themicrostructureandporosityofC/Ccompositescanalsoaffecttheirtribologicalbehavior.Higherporositycanleadtoincreasedwearandlowermechanicalproperties,whileamorehomogeneousmicrostructurecanleadtomoreuniformwearandareductioninsurfacedamage.Therefore,itisimportanttocarefullycontrolthemanufacturingprocesstoensurethatthedesiredmicrostructureandporosityareachieved.

Finally,thedesignandprocessingofC/Ccompositescanalsohaveasignificantimpactontheirtribologicalbehavior.Theuseofadvancedmanufacturingtechniques,suchas3Dprintingandadditivemanufacturing,canimprovethequalityandconsistencyofC/Ccomposites,leadingtobettertribologicalperformance.Additionally,theoptimizationofdesignparameters,suchasfibervolumefractionandmatrixdensity,canfurtherenhancethetribologicalpropertiesofC/Ccomposites.

Inconclusion,therearemanyfactorstoconsiderwhenevaluatingthetribologicalbehaviorofC/Ccomposites.Advancesinmaterialscienceandengineering,alongwithimprovementsinmanufacturingprocessesanddesignoptimization,haveenabledthedevelopmentofC/Ccompositeswithexcellenttribologicalproperties.However,continuedresearchanddevelopmentinthisareaareessentialtofurtherimprovetheperformanceandreliabilityofthesematerialsandtoexploretheirpotentialinawiderangeofindustrialapplications.AnotherimportantaspecttoconsiderwhenevaluatingthetribologicalbehaviorofC/Ccompositesisthetemperatureandoperatingenvironment.Thesematerialshaveexcellentthermalstabilityandarecapableofoperatingathightemperatures,makingthemsuitableforvarioushigh-temperatureapplications.However,extremetemperaturesorcorrosiveenvironmentscanaffectthetribologicalpropertiesofC/Ccomposites.

Athightemperatures,thethermalexpansioncoefficientofC/Ccompositesincreases,whichcanleadtothermalstressandcracking.Thiscanresultinincreasedwearanddecreasedmechanicalperformance.Inaddition,oxidationorchemicalreactionswiththeenvironmentcanalsooccur,leadingtosurfacedamageandareductionintribologicalproperties.

Tomitigatetheseeffects,protectivecoatingsorlubricantscanbeusedtominimizecontactbetweenthematerialandtheenvironment.Additionally,theuseofadditivesorfillerscanimprovethethermalandchemicalstabilityofC/Ccomposites,leadingtobettertribologicalperformanceinharshenvironments.

AnotherfactorthatcanaffectthetribologicalbehaviorofC/Ccompositesisthetypeandintensityoftheappliedload.Differenttypesofloads,suchassliding,rolling,orimpactload,canaffectthewearandfrictionpropertiesofC/Ccompositesdifferently.Inaddition,theintensityanddurationoftheloadcanalsoaffectthetribologicalbehaviorofthesematerials.

Finally,thesurfacefinishandroughnessofC/Ccompositescanalsohaveasignificantimpactontheirtribologicalproperties.Asmoothsurfacefinishcanleadtolowerfrictionandwear,whilearoughsurfacecanleadtoincreasedfrictionandwear.Therefore,itisimportanttocarefullycontrolthesurfacefinishofthesematerialstoachievethedesiredtribologicalproperties.

Insummary,thetribologicalbehaviorofC/Ccompositesisaffectedbyvariousfactors,suchasthepresenceofcontaminants,microstructureandporosity,designandprocessing,temperatureandoperatingenvironment,appliedload,andsurfacefinish.ContinuedresearchanddevelopmentarenecessarytofurtherunderstandandoptimizethesefactorstoimprovethetribologicalperformanceofC/Ccompositesforawiderangeofindustrialapplications.Inadditiontotheaforementionedfactors,thetribologicalbehaviorofC/Ccompositescanalsobeinfluencedbythemanufacturingprocessesusedtoproducethem.ThepropertiesofC/Ccompositesareheavilydependentontheprocessingconditions,suchasthetypeofcarbonprecursor,thepyrolysistemperatureandtime,andthepressureandtemperatureappliedduringdensification.

Forexample,theuseofdifferentcarbonprecursorscanresultinvariationsinthemicrostructureandcompositionofC/Ccomposites,ultimatelyaffectingtheirtribologicalbehavior.Similarly,theuseofdifferentprocessingtechniques,suchashotpressingorchemicalvaporinfiltration,canleadtodifferencesinthedensity,porosity,andmechanicalpropertiesofC/Ccomposites.Thesedifferencesinpropertiescaninfluencethetribologicalbehaviorofthematerial.

ThegeometryanddesignofC/Ccompositescanalsoaffecttheirtribologicalbehavior.Theshapeandsizeofthecomponentcaninfluencethetypeandintensityofthecontact,whichcanaffectthewearandfrictionpropertiesofthematerial.Theinclusionoffeaturessuchasgrooves,coatings,orsurfacetreatmentscanalsoimpactthetribologicalpropertiesofC/Ccomposites.

Overall,thetribologicalbehaviorofC/Ccompositesisacomplexphenomenonthatisinfluencedbyvariousfactors,includingbutnotlimitedtotheoperatingenvironment,appliedload,manufacturingprocesses,andgeometricdesign.UnderstandingthesefactorsandoptimizingthematerialsandprocessingtechniquestoimprovetribologicalperformanceisessentialtoexpandtherangeofapplicationsforC/Ccompositesinindustriessuchasaerospace,automotive,andenergy.Inrecentyears,therehasbeenagrowinginterestinthedevelopmentofhigh-performanceC/Ccompositesfortribologicalapplications.Thisisduetotheiruniquecombinationofproperties,suchashightemperatureresistance,lowcoefficientoffriction,andhighwearresistance.

OneareawhereC/Ccompositeshaveshownpromiseisintheaerospaceindustry,wheretheyarebeingusedincomponentssuchasbrakediscs,bearings,andseals.Intheseapplications,C/Ccompositesofferadvantagessuchasimprovedbrakingperformance,reducedweight,andincreaseddurability.Similarly,intheautomotiveindustry,C/Ccompositesarebeingusedinbrakecomponentsandclutchfacings,wheretheirlowwearrateandexcellentthermalstabilityarecriticalforsafetyandperformance.

Intheenergysector,C/Ccompositesarebeingexploredforuseinnuclearreactorcomponents,suchascontrolrodsandfuelcladding.Thehigh-temperaturestabilityandradiationresistanceofC/Ccompositesmakethemanattractiveoptionfortheseapplications.

Inadditiontotheseapplications,C/Ccompositesalsohavepotentialinotherareassuchassportsequipment,biomedicalimplants,andelectricalcontacts.Theiruniquetribologicalpropertiesmakethemsuitableforawiderangeofapplicationswherehighperformanceanddurabilityarecritical.

Overall,thetribologicalbehaviorofC/Ccompositesisacomplexphenomenonthatdependsonvariousfactors,andunderstandingthesefactorsiscrucialfordevelopinghigh-performancematerialsforspecificapplications.Withongoingresearchanddevelopment,C/Ccompositeshavethepotentialtorevolutionizethetribologicalpropertiesofmaterialsandenablenewinnovationsinvariousindustries.On