微纳米力学测试课件

微纳米力学测试力学性能

是评价材料质量的主要指标，也是进行设计与计算的主要依据，不同的应用领域对材料的力学性能要求也不一样 钢材 塑料 橡胶 纤维 胶黏剂 涂层或镀层模量、硬度、强度、结合力、摩擦性能 力学性能的评价1、简单应力状态实验 单轴拉伸、压缩和扭转 获得：应力、应变数据

由于制样的局限性只适合尺度在100μm量级的样品2、复杂应力状态的接触试验 硬度实验 表征材料抵抗局部变形的能力，是衡量材料软硬程度的性能指标

由于只在材料表面局部产生很小的压痕，使其比较适合微尺度材料常规硬度测量方法静态压入硬度 通过球体、金刚石椎体或其他椎体经载荷施加到被测材料上，使材料发生塑性形变，再根据总施加载荷与所产生的压入面积或深度之间的关系，给出其硬度值。 宏观硬度；2N≤P≤30KN 显微硬度：P≤2N，h≥0.2μ 纳米硬度：h≤0.2μ动态或回弹压入硬度（载荷与回弹高度，主要用于金属材料）划入硬度（法向力、划痕，材料抗划入、摩擦、变形、附着力）ComparativeLoadRanges纳米压入和划入的特点操作方便连续记录载荷和压入深度，从载荷-位移曲线中获得硬度、模量样品制备简单 对样品的尺寸和形状无特殊要求，薄膜、涂层、表面改性样品测量和定位分辨率高 100nN,1nm测试内容丰富 硬度、模量、断裂韧度、应力-应变曲线、高聚物的存储模量、蠕变特性、疲劳特性、粘附；薄膜的临界附着力、摩擦系数等适用范围广泛 金属、陶瓷、高聚物、复合材料、表面工程系统、微系统器件、生物材料TechniquesAvailableTodayLoad,displacement&timeHardnessandModulusContinuousStiffnessMeasurementCreepandStressExponentFractureToughnessStorageandLossModulusScratchandFrictionProfilometry(台阶仪功能）3DImaging(原位成像)ConventionalMicrohardnessApplyaspecificloadonadiamondindenterTheresidualimpressionafterloadremovalisameasureofhardnessLoadConventionalMicrohardnessDiagonal,D,ismeasuredopticallyafterremovalofloadVickers（维氏）:D=7hKnoop（努氏）:D=30.5hWhatisDepth-SensingIndentation?Applyaspecific,quasi-staticordynamic,load-timehistoryonadiamondindenterMeasurethedisplacement-timeresponseUsethesedatatoextractcertainmechanicalpropertiesbasedonanalyticalmodelsHardness,Young’sModulus,Stress-ExponentforCreep,StorageModulus,LossModulus,etc.Hardness&Young’sModulusHardnessisthemeanpressurethematerialwillsupportYoung’smodulusiscalculatedfromthecompositeresponsemodulus,ErThoughnotshownexplicitlyhere,bothHandErequireload,depthandstiffnessforcalculationsLoad-DisplacementBehaviorAluminum（铝）,typicalofsoftmetallicbehavior,showsverylittledisplacementrecoveryuponunloadingFusedsilica（熔融石英）,typicalofceramicbehavior,showslargeelasticrecoveryuponunloadingAluminumFusedsilicaElastic/PlasticIndentationsForanideallyplasticindentation（塑性压痕）,hc

（接触深度）≈ht（穿透深度，最大位移）

Foranelastic/plasticindentation,hc

<htStiffnessFromUnloadinghn,PnModelingtheP-hbehaviorTheunloadingcurve（卸载曲线）followsapowerlawContactstiffness（接触硬度）istheslopeoftheunloadingcurveContactdepth（接触深度）isdeterminedfromthedisplacement,load,andcontactstiffnessContactArea(thetipfunction)The“tipfunction”fortheidealBerkovich（玻氏）tipExperimentaltipfunctionArbitraryformCoefficientsdeterminedexperimentallyPolymerthinfilmProblemswithTime-Dependence(粘弹塑性材料)“Conventional”stiffnessdeterminationunreasonableLargeamountsoftime-dependentdeformationLargetime-dependentrecoveryContinuousStiffnessMeasurementTechnique

（连续刚度测量技术CSM）PatentedMethodfortheContinuousDeterminationoftheElasticStiffnessofContactBetweenTwoBodies“Frequency-Specific（固定频率）,Depth-SensingIndentation.”CSM-ForceOscillation（固定频率的简谐力）CSM-Elastic&ViscoelasticElasticViscoelastic-2-1012-1-0.500.5101020304050Excitationforce(µN)Responsedisplacement(nm)Time(milliseconds)fDynamicModelA.SampleB.IndenterColumn;mass=mC.LoadApplicationCoilD.IndenterSupportSprings;Stiffness=Ks

E.CapacitiveDisplacementGauge;DampingCoefficient=DiF.LoadFrame;Stiffness=KfABCDEFMass=mK

SsDiKfDsStiffnessCalculationbyCSMTechniqueBenefitsofCSMPropertiesvs.depth---avoidingsubstrateeffect（基底效应）ControllablestrainrateTipcalibrationSurfacecontactdeterminationViscoelasticmaterialsandpropertiesThinFilmTestingwithoutCSMUnloadingdataUnloadsat0.1,0.5and1.0timesthicknessValuesimplyfilmhardnessvarieslinearlywithdepthAlfilmonglass0.511.520200400600800Hardness(GPa)Depth,h(nm)h=th=0.5th=0.1t%offilmthickness020406080100ThinFilmTestingwithCSMCSMdataContinuousdatawiththickness(i.e.,depth)showstruecharacteroffilmAlfilmonglassCSM-AluminumThinFilmsContinuousmeasureofhardnesswithdepthEachcurveisanaverageoftenindentationsFrom10nmto2µmwitheachindentation“Plateaus”inhardnessvarywithfilmthicknessAlfilmsonglassTipCalibration(压头校准)–StandardMethodResultsof60indentationsshownLargegapsindataTipCalibration–CSMMethodResultsofsame20indentationsshownMorepointsformoredensedataTipCalibration–ShallowDepthsCSMgiveshigherdatadensityCSMgiveslowernoiseThusCSMgivesmorereliablecalibrationoftipshapeSurfaceContactDetermination（表面探测）

(Criticallyimportantforverythinfilmsandsoftmaterials)

1、拟合函数，外推法确定零点

2、载荷或接触刚度的首次增加为零点PointofContact?AccuTip™BerkovichDiamondTipsThesharperthetip,theshalloweranindentcanbemadetogivereliablehardnessvaluesDeepindentrequiredShallowindentpossibleIdealtipAccuTip™BerkovichDiamondTipsOlddiamondtipsFaceangles（中心线与面的夹角）fairlyconsistent,butnotknownwithanyprecisionTipradiustypically~100–150nmNewAccuTip™BerkovichdiamondtipsFaceanglesknownto±0.025˚Tipradius≤50nm(typically~40nm)before2007Tipradius≤20nmsince2008OldBerkovichDiamondTipTwodifferentDLCfilms,both20nmthickNosignificantdifferencebetweenthemmeasuredPlasticitydoesnotbeginatashallowenoughindentdepthtoseeasignificanteffectofthefilminthemeasurementTipSharpnessSharptipDulltipHardnessDepthofpenetrationAsharptipisrequiredformakinghardnessmeasurementsatveryshallowindentationdepthsAccuTip™BerkovichdiamondTipTwodifferentDLCfilms,both20nmthick–

samefilmsshowninpreviousslideStatisticallysignificantdifferencebetweenthetwoPlasticitybeginsatashallowerindentdepth–shallowenoughtoseeasignificanteffectofthefilminthemeasurementHardcoating&surfacemodificationIonImplantationofHardChromePlatingTiCCoatedBallBearingsOpticalCoatings-SiloxaneonPCMicroElectronicMachines(MEMS)TheNanoIndenterXPmakesagreatMEMSTesterLFMmicrotensileDoubledogbonemicro-tensileRaytheonRFMEMSSwitchYoung’smodulusofmembraneveryimportantforswitchperformanceNeedtodeflectmembranewithoutcomplicatedstressstatesPublishedbyH.D.Espinosa,M.Fischer,NorthwesternUniversityandE.Herbert,W.C.Oliver,MTSNanoInstrumentsDiamondTipGeometryMoreacutediamondwedgeObtuseanglediamondwedgewilllimitamountofverticaldisplacementpossibleMembraneDeflection（膜偏离）ExperimentsWithdiamondwedgewiderthanmembrane,lineloadisappliedandrelativelysimplestressesandmodelsresultPublishedbyH.D.Espinosa,M.Fischer,NorthwesternUniversityandE.Herbert,W.C.Oliver,MTSNanoInstruments3N/mExperimentalE=52.0Gpa(1isotropicmat’l)E1=73.2Gpa;E2=44.0Gpa

0100020003000048121620Displacement(nm)Force(µN)Lineload(flat)s0=5MPaMembraneDeflectionStiffnessesaslowas2-3N/mweremeasuredquitereproduciblywiththestandardNanoIndenter®XPheadPublishedbyH.D.Espinosa,M.Fischer,NorthwesternUniversityandE.Herbert,W.C.Oliver,MTSNanoInstrumentsAccuTip™DiamondTips

ScratchTesting

划痕测试ScratchFrictionCoefficientFNFTstindentermaterialMotionofindenterScratchfrictioncoefficient划痕摩擦系数Actualfrictioncoefficient实际摩擦系数(Indentergeometrydependent)(samewithBerkovichandCubeCorner)ScratchtestingwithaBerkovichLowangleofattack（小接触角）Plasticdeformation（塑性变形）Faceforward面划入Edgeforward（棱划入）-1200-1000-800-600-400-200020040060080020304050607080profiledistance(um)profileheight(nm)ahbpFractureInitiation:CriticalLoadMeasurement050010001500200025000100200300400500600700scratchdistance(um)indenterpenetration(nm)Pc=2.5mNhc=1500nmPenetrationunderloadResidualscratchdepthStudyoffracturedamagemechanisms（破裂损坏机理）CubeCornerindenterChippingprocessImportantparameters:Inde