微納米力學測試

1、中山大學環(huán)境材料所中山大學環(huán)境材料所微納米力學測試微納米力學測試中山大學環(huán)境材料所中山大學環(huán)境材料所力學性能是評價材料質(zhì)量的主要指標，也是進行設計與計算的主要依據(jù)，不同的應用領(lǐng)域?qū)Σ牧系牧W性能要求也不一樣 鋼材塑料橡膠纖維膠黏劑涂層或鍍層模量、硬度、強度、結(jié)合力、摩擦性能中山大學環(huán)境材料所中山大學環(huán)境材料所力學性能的評價力學性能的評價1、簡單應力狀態(tài)實驗單軸拉伸、壓縮和扭轉(zhuǎn)獲得：應力、應變數(shù)據(jù)2、復雜應力狀態(tài)的接觸試驗硬度實驗表征材料抵抗局部變形的能力，是衡量材料軟硬程度的性能指標由于只在材料表面局部產(chǎn)生很小的壓痕，使其比較適合微由于只在材料表面局部產(chǎn)生很小的壓痕，使其比較適合微尺度材料尺度

2、材料中山大學環(huán)境材料所中山大學環(huán)境材料所常規(guī)硬度測量方法常規(guī)硬度測量方法靜態(tài)壓入硬度靜態(tài)壓入硬度通過球體、金剛石椎體或其他椎體經(jīng)載荷施加到被測材料上，使材料發(fā)生塑性形變，再根據(jù)總施加載荷與所產(chǎn)生的壓入面積或深度之間的關(guān)系，給出其硬度值。宏觀硬度；2NP30KN顯微硬度：P2N，h0.2納米硬度：h0.2動態(tài)或回彈壓入硬度動態(tài)或回彈壓入硬度（載荷與回彈高度，主要用于金屬材料）劃入硬度劃入硬度（法向力、劃痕，材料抗劃入、摩擦、變形、附著力）中山大學環(huán)境材料所中山大學環(huán)境材料所Comparative Load Ranges10-510-410-310-210-11001011021031041051

3、06107BrinellRockwellRockwell SuperficialConventionalMicrohardnessNano IndentationUniversalTestingSystemsLoad(grams)中山大學環(huán)境材料所中山大學環(huán)境材料所納米壓入和劃入的特點納米壓入和劃入的特點操作方便 連續(xù)記錄載荷和壓入深度，從載荷-位移曲線中獲得硬度、模量樣品制備簡單對樣品的尺寸和形狀無特殊要求，薄膜、涂層、表面改性樣品測量和定位分辨率高100nN, 1nm測試內(nèi)容豐富硬度、模量、斷裂韌度、應力-應變曲線、高聚物的存儲模量、蠕變特性、疲勞特性、粘附；薄膜的臨界附著力、摩擦系數(shù)等適

4、用范圍廣泛金屬、陶瓷、高聚物、復合材料、表面工程系統(tǒng)、微系統(tǒng)器件、生物材料中山大學環(huán)境材料所中山大學環(huán)境材料所Techniques Available TodayLoad, displacement & timeHardness and Modulus Continuous Stiffness MeasurementCreep and Stress ExponentFracture ToughnessStorage and Loss ModulusScratch and FrictionProfilometry(臺階儀功能）3D Imaging (原位成像)中山大學環(huán)境材料所中山大學環(huán)

5、境材料所Conventional MicrohardnessApply a specific load on a diamond indenterThe residual impression after load removal is a measure of hardnessLoad中山大學環(huán)境材料所中山大學環(huán)境材料所HV 1854.4PD2HK 14,229PD2Conventional MicrohardnessDiagonal, D, is measured optically after removal of loadVickers（維氏）: D = 7hKnoop（努氏）: D

6、= 30.5hhDVickersDKnoop中山大學環(huán)境材料所中山大學環(huán)境材料所What is Depth-Sensing Indentation?Apply a specific, quasi-static or dynamic, load-time history on a diamond indenterMeasure the displacement-time responseUse these data to extract certain mechanical properties based on analytical modelsHardness, Youngs Modulus

7、, Stress-Exponent for Creep, Storage Modulus, Loss Modulus, etc.中山大學環(huán)境材料所中山大學環(huán)境材料所Hardness & Youngs ModulusHardness is the mean pressure the material will supportYoungs modulus is calculated from the composite response modulus, ErThough not shown explicitly here, both H and E require load, depth

8、 and stiffness for calculationsH PAdhdPrASE/S)S(A12為卸載曲線頂部斜率彈性接觸韌度是接觸面積的常數(shù)是與壓頭幾何形狀相關(guān)中山大學環(huán)境材料所中山大學環(huán)境材料所0510152025300100200300400500Load (mN)Displacement (nm)0510152025300500100015002000Load (mN)Load-Displacement BehaviorAluminum（鋁）（鋁）, typical of soft metallic behavior, shows very little displacement

9、 recovery upon unloadingFused silica（熔融石英）（熔融石英）, typical of ceramic behavior, shows large elastic recovery upon unloadingAluminumFused silica中山大學環(huán)境材料所中山大學環(huán)境材料所Elastic/Plastic IndentationsFor an ideally plastic indentation（塑性壓痕）, hc （接觸深度） ht（穿透深度，最大位移）For an elastic/plastic indentation, hc htSAMPLE

10、 e.g. CuINDENTERSAMPLE e.g. Al2O3INDENTERhchtht = hc中山大學環(huán)境材料所中山大學環(huán)境材料所Stiffness From Unloading01020300100200300400500600Load (mN)Displacement (nm)slope = Shthc for = 0.75hn, Pn中山大學環(huán)境材料所中山大學環(huán)境材料所hc htPmaxSModeling the P-h behaviorThe unloading curve（卸載曲線）（卸載曲線） follows a power lawContact stiffness（接觸

11、硬度）（接觸硬度） is the slope of the unloading curveContact depth（接觸深度）（接觸深度） is determined from the displacement, load, and contact stiffnessmaxPdhdPS mhP中山大學環(huán)境材料所中山大學環(huán)境材料所Contact Area (the tip function)The “tip function” for the ideal Berkovich（玻氏）（玻氏） tipExperimental tip function Arbitrary form Coeffici

12、ents determined experimentallyA 24.56hc2Cihc12ii07A 24.56hc2中山大學環(huán)境材料所中山大學環(huán)境材料所0501001500400080001200016000Load (mN)Displacement (nm)Time-dependent deformationTime-dependent recoveryNegative stiffness?Polymer thin filmProblems with Time-Dependence(粘彈塑性材料粘彈塑性材料)“Conventional” stiffness determination u

13、nreasonableLarge amounts of time-dependent deformationLarge time-dependent recovery中山大學環(huán)境材料所中山大學環(huán)境材料所Continuous Stiffness Measurement Technique（連續(xù)剛度測量技術(shù)（連續(xù)剛度測量技術(shù)CSM）Patented Method for the Continuous Determination of the Elastic Stiffness of Contact Between Two Bodies“Frequency-Specific（固定頻率）, Depth

14、-Sensing Indentation.”中山大學環(huán)境材料所中山大學環(huán)境材料所9.951010.054.9555.05Nominal ForceExcitation ForceLoad (mN)Time (seconds)02468101201020304050607080Nominal Force, P/P = ConstantLoad (mN)Time (seconds).CSM - Force Oscillation（固定頻率的簡諧力）（固定頻率的簡諧力）中山大學環(huán)境材料所中山大學環(huán)境材料所CSM - Elastic & Viscoelastic-2-1012-1-0.500.

15、5101020304050Excitation force (N)Response displacement (nm)Time (milliseconds)ElasticViscoelastic-2-1012-1-0.500.5101020304050Excitation force (N)Response displacement (nm)Time (milliseconds)f中山大學環(huán)境材料所中山大學環(huán)境材料所Dynamic ModelA. Sample B. Indenter Column; mass=m C. Load Application Coil D. Indenter Sup

16、port Springs; Stiffness=Ks E. Capacitive Displacement Gauge; Damping Coefficient=DiF. Load Frame; Stiffness=KfABCDEFMass = mK SsDiKfDs中山大學環(huán)境材料所中山大學環(huán)境材料所Stiffness Calculation by CSM TechniquefioosDZFDsin121cos1fSooKKmZFSf中山大學環(huán)境材料所中山大學環(huán)境材料所Benefits of CSMProperties vs. depth-avoiding substrate effect（

17、基底效應）Controllable strain rateTip calibrationSurface contact determinationViscoelastic materials and properties中山大學環(huán)境材料所中山大學環(huán)境材料所Thin Film Testing without CSMUnloading data Unloads at 0.1, 0.5 and 1.0 times thickness Values imply film hardness varies linearly with depthAl film on glass0.511.520200400

18、600800Hardness (GPa)Depth, h (nm)h = th = 0.5th = 0.1t% of film thickness020406080100中山大學環(huán)境材料所中山大學環(huán)境材料所Thin Film Testing with CSMCSM data Continuous data with thickness (i.e., depth) shows true character of filmAl film on glass0.511.520200400600800CSM dataunloading dataHardness (GPa)Depth, h (nm)h =

19、 th = 0.5th = 0.1t% of film thickness020406080100中山大學環(huán)境材料所中山大學環(huán)境材料所01234561010010001040.50.751.52.0Hardness (GPa)Depth (nm)Film Thickness (Microns)CSM - Aluminum Thin FilmsContinuous measure of hardness with depth Each curve is an average of ten indentations From 10 nm to 2 m with each indentation “

20、Plateaus” in hardness vary with film thicknessAl films on glass中山大學環(huán)境材料所中山大學環(huán)境材料所Tip Calibration(壓頭校準壓頭校準) Standard MethodResults of 60 indentations shownLarge gaps in data01 1072 1073 1074 1075 1076 107050010001500Unloading data onlyContact Area (nm2)Contact Depth (nm)中山大學環(huán)境材料所中山大學環(huán)境材料所01 1072 1073

21、 1074 1075 10702004006008001000 1200 1400CSM 3 nm windowsContact Area (nm2)Contact Depth (nm)Tip Calibration CSM MethodResults of same 20 indentations shownMore points for more dense data中山大學環(huán)境材料所中山大學環(huán)境材料所02 1044 1046 1048 1041 10501020304050Unloading data onlyCSM 3 nm windowsCSM 20 nm windowsContac

22、t Area (nm2)Contact Depth (nm)Tip Calibration Shallow DepthsCSM gives higher data densityCSM gives lower noiseThus CSM gives more reliable calibration of tip shape中山大學環(huán)境材料所中山大學環(huán)境材料所-2 10-502 10-54 10-56 10-58 10-50.0001-5005010015050556065707580Load (mN)S (N/m)Load (mN)Contact Stiffness (N/m)Quasi-s

23、tatic Displacement (nm)Surface Contact Determination（表面探測）（表面探測）(Critically important for very thin films and soft materials)1、擬合函數(shù)，外推法確定零點、擬合函數(shù)，外推法確定零點2、載荷或接觸剛度的首次增加為零點、載荷或接觸剛度的首次增加為零點Point of Contact ?中山大學環(huán)境材料所中山大學環(huán)境材料所AccuTip Berkovich Diamond TipsThe sharper the tip, the shallower an indent can

24、be made to give reliable hardness valuesDeep indent requiredShallow indent possibleIdeal tip中山大學環(huán)境材料所中山大學環(huán)境材料所AccuTip Berkovich Diamond TipsOld diamond tips Face angles（中心線與面的夾角） fairly consistent, but not known with any precision Tip radius typically 100 150 nmNew AccuTip Berkovich diamond tips Fac

25、e angles known to 0.025 Tip radius 50 nm (typically 40 nm) before 2007 Tip radius 20 nm since 2008中山大學環(huán)境材料所中山大學環(huán)境材料所Old Berkovich Diamond TipTwo different DLC films, both 20 nm thickNo significant difference between them measuredPlasticity does not begin at a shallow enough indent depth to see a sig

26、nificant effect of the film in the measurement中山大學環(huán)境材料所中山大學環(huán)境材料所Tip SharpnessSharp tipDull tipHardnessDepth of penetrationA sharp tip is required for making hardness measurements at very shallow indentation depths中山大學環(huán)境材料所中山大學環(huán)境材料所AccuTip Berkovich diamond TipTwo different DLC films, both 20 nm thic

27、k same films shown in previous slideStatistically significant difference between the twoPlasticity begins at a shallower indent depth shallow enough to see a significant effect of the film in the measurement中山大學環(huán)境材料所中山大學環(huán)境材料所Hard coating & surface modification中山大學環(huán)境材料所中山大學環(huán)境材料所Ion Implantation o

28、f Hard Chrome Plating0510152002004006008001000Control 3/4/97PSII 3/4/97Control 3/5/97PSII 3/5/97Control 3/10/97PSII 3/10/97Hardness (GPa)Displacement (nm)中山大學環(huán)境材料所中山大學環(huán)境材料所TiC Coated Ball Bearings中山大學環(huán)境材料所中山大學環(huán)境材料所Optical Coatings - Siloxane on PC012345678050100150200250300Average Hardness (GPa)Disp

29、lacement (nm)中山大學環(huán)境材料所中山大學環(huán)境材料所Micro Electronic Machines (MEMS)The Nano Indenter XP makes a great MEMS Tester LFM micro tensile Double dog bone micro-tensile中山大學環(huán)境材料所中山大學環(huán)境材料所Raytheon RF MEMS SwitchYoungs modulus of membrane very important for switch performanceNeed to deflect membrane without compl

30、icated stress statesPublished by H.D. Espinosa, M. Fischer, Northwestern University and E. Herbert, W.C. Oliver, MTS Nano Instruments中山大學環(huán)境材料所中山大學環(huán)境材料所Diamond Tip GeometryMore acute diamond wedgeObtuse angle diamond wedge will limit amount of vertical displacement possible中山大學環(huán)境材料所中山大學環(huán)境材料所Membrane

31、Deflection（膜偏離）（膜偏離） ExperimentsWith diamond wedge wider than membrane, line load is applied and relatively simple stresses and models resultLINE LOADWEDGE TIPSUBSTRATEMEMBRANEELECTRODEPublished by H.D. Espinosa, M. Fischer, Northwestern University and E. Herbert, W.C. Oliver, MTS Nano Instruments中山

32、大學環(huán)境材料所中山大學環(huán)境材料所3 N/mExperimentalE = 52.0 Gpa (1 isotropic matl)E1 = 73.2 Gpa; E2 = 44.0 Gpa 0100020003000048121620Displacement (nm)Force (N)Line load (flat)s0 = 5 MPaMembrane DeflectionStiffnesses as low as 2 - 3 N/m were measured quite reproducibly with the standard Nano Indenter XP headPublished

33、by H.D. Espinosa, M. Fischer, Northwestern University and E. Herbert, W.C. Oliver, MTS Nano Instruments中山大學環(huán)境材料所中山大學環(huán)境材料所AccuTip Diamond TipsScratch Testing劃痕測試劃痕測試中山大學環(huán)境材料所中山大學環(huán)境材料所Scratch Friction CoefficientFNFTstindentermaterialMotion of indenterScratch friction coefficient劃痕摩擦系數(shù)Actual friction

34、coefficient實際摩擦系數(shù)NTsFFf staf(Indenter geometry dependent)(same with Berkovich and Cube Corner)中山大學環(huán)境材料所中山大學環(huán)境材料所Scratch testing with a BerkovichLow angle of attack（小接觸角）Plastic deformation（塑性變形）Face forward面劃入Edge forward（棱劃入）中山大學環(huán)境材料所中山大學環(huán)境材料所-1200-1000-800-600-400-200020040060080020304050607080profile distance (um)profile height (nm)ahbp中山大學環(huán)境材料所中山大學環(huán)境材料所Fracture Initiation: Critical Load Measurement050010001500200025000100200300400500600700scratch distance (um)indenter penetration (nm)Pc= 2.5 mNhc= 1500 nmPenetration under loadResidual scratc