1、中山大学环境材料所中山大学环境材料所微纳米力学测试微纳米力学测试中山大学环境材料所中山大学环境材料所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、摩擦性能中山大学环境材料所中山大学环境材料所力学性能的评价力学性能的评价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尺度
2、材料中山大学环境材料所中山大学环境材料所常规硬度测量方法常规硬度测量方法静态压入硬度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；2NP30KN显微硬度：P2N，h0.2纳米硬度：h0.2动态或回弹压入硬度动态或回弹压入硬度（载荷与回弹高度，主要用于金属材料）划入硬度划入硬度（法向力、划痕，材料抗划入、摩擦、变形、附着力）中山大学环境材料所中山大学环境材料所Comparative Load Ranges10-510-410-310-210-11001011021031041051
3、06107BrinellRockwellRockwell SuperficialConventionalMicrohardnessNano IndentationUniversalTestingSystemsLoad(grams)中山大学环境材料所中山大学环境材料所纳米压入和划入的特点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
4、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、生物材料中山大学环境材料所中山大学环境材料所Techniques Available TodayLoad, displacement & timeHardness and Modulus Continuous Stiffness MeasurementCreep and Stress ExponentFracture ToughnessStorage and Loss ModulusScratch and FrictionProfilometry(台阶仪功能）3D Imaging (原位成像)中山大学环境材料所中山大学环境材料所
5、Conventional MicrohardnessApply a specific load on a diamond indenterThe residual impression after load removal is a measure of hardnessLoad中山大学环境材料所中山大学环境材料所HV 1854.4PD2HK 14,229PD2Conventional MicrohardnessDiagonal, D, is measured optically after removal of loadVickers（维氏）: D = 7hKnoop（努氏）: D = 30
6、.5hhDVickersDKnoop中山大学环境材料所中山大学环境材料所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, St
7、ress-Exponent for Creep, Storage Modulus, Loss Modulus, etc.中山大学环境材料所中山大学环境材料所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 and sti
8、ffness for calculationsH PAdhdPrASE/S)S(A12为卸载曲线顶部斜率弹性接触韧度是接触面积的常数是与压头几何形状相关中山大学环境材料所中山大学环境材料所0510152025300100200300400500Load (mN)Displacement (nm)0510152025300500100015002000Load (mN)Load-Displacement BehaviorAluminum（铝）（铝）, typical of soft metallic behavior, shows very little displacement recover
9、y upon unloadingFused silica（熔融石英）（熔融石英）, typical of ceramic behavior, shows large elastic recovery upon unloadingAluminumFused silica中山大学环境材料所中山大学环境材料所Elastic/Plastic IndentationsFor an ideally plastic indentation（塑性压痕）, hc （接触深度） ht（穿透深度，最大位移）For an elastic/plastic indentation, hc htSAMPLE e.g. Cu
10、INDENTERSAMPLE e.g. Al2O3INDENTERhchtht = hc中山大学环境材料所中山大学环境材料所Stiffness From Unloading01020300100200300400500600Load (mN)Displacement (nm)slope = Shthc for = 0.75hn, Pn中山大学环境材料所中山大学环境材料所hc htPmaxSModeling the P-h behaviorThe unloading curve（卸载曲线）（卸载曲线） follows a power lawContact stiffness（接触硬度）（接触硬度
11、） is the slope of the unloading curveContact depth（接触深度）（接触深度） is determined from the displacement, load, and contact stiffnessmaxPdhdPS mhP中山大学环境材料所中山大学环境材料所Contact Area (the tip function)The “tip function” for the ideal Berkovich（玻氏）（玻氏） tipExperimental tip function Arbitrary form Coefficients det
12、ermined experimentallyA 24.56hc2Cihc12ii07A 24.56hc2中山大学环境材料所中山大学环境材料所0501001500400080001200016000Load (mN)Displacement (nm)Time-dependent deformationTime-dependent recoveryNegative stiffness?Polymer thin filmProblems with Time-Dependence(粘弹塑性材料粘弹塑性材料)“Conventional” stiffness determination unreasona
13、bleLarge amounts of time-dependent deformationLarge time-dependent recovery中山大学环境材料所中山大学环境材料所Continuous Stiffness Measurement Technique（连续刚度测量技术（连续刚度测量技术CSM）Patented Method for the Continuous Determination of the Elastic Stiffness of Contact Between Two Bodies“Frequency-Specific（固定频率）, Depth-Sensing
14、 Indentation.”中山大学环境材料所中山大学环境材料所9.951010.054.9555.05Nominal ForceExcitation ForceLoad (mN)Time (seconds)02468101201020304050607080Nominal Force, P/P = ConstantLoad (mN)Time (seconds).CSM - Force Oscillation（固定频率的简谐力）（固定频率的简谐力）中山大学环境材料所中山大学环境材料所CSM - Elastic & Viscoelastic-2-1012-1-0.500.510102030405
15、0Excitation force (N)Response displacement (nm)Time (milliseconds)ElasticViscoelastic-2-1012-1-0.500.5101020304050Excitation force (N)Response displacement (nm)Time (milliseconds)f中山大学环境材料所中山大学环境材料所Dynamic ModelA. Sample B. Indenter Column; mass=m C. Load Application Coil D. Indenter Support Springs
16、; Stiffness=Ks E. Capacitive Displacement Gauge; Damping Coefficient=DiF. Load Frame; Stiffness=KfABCDEFMass = mK SsDiKfDs中山大学环境材料所中山大学环境材料所Stiffness Calculation by CSM TechniquefioosDZFDsin121cos1fSooKKmZFSf中山大学环境材料所中山大学环境材料所Benefits of CSMProperties vs. depth-avoiding substrate effect（基底效应）Control
17、lable strain rateTip calibrationSurface contact determinationViscoelastic materials and properties中山大学环境材料所中山大学环境材料所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 glass0.511.520200400600800Hardne
18、ss (GPa)Depth, h (nm)h = th = 0.5th = 0.1t% of film thickness020406080100中山大学环境材料所中山大学环境材料所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 = th = 0.5th
19、= 0.1t% of film thickness020406080100中山大学环境材料所中山大学环境材料所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 “Plateaus” in
20、 hardness vary with film thicknessAl films on glass中山大学环境材料所中山大学环境材料所Tip Calibration(压头校准压头校准) Standard MethodResults of 60 indentations shownLarge gaps in data01 1072 1073 1074 1075 1076 107050010001500Unloading data onlyContact Area (nm2)Contact Depth (nm)中山大学环境材料所中山大学环境材料所01 1072 1073 1074 1075 1
21、0702004006008001000 1200 1400CSM 3 nm windowsContact Area (nm2)Contact Depth (nm)Tip Calibration CSM MethodResults of same 20 indentations shownMore points for more dense data中山大学环境材料所中山大学环境材料所02 1044 1046 1048 1041 10501020304050Unloading data onlyCSM 3 nm windowsCSM 20 nm windowsContact Area (nm2)
22、Contact Depth (nm)Tip Calibration Shallow DepthsCSM gives higher data densityCSM gives lower noiseThus CSM gives more reliable calibration of tip shape中山大学环境材料所中山大学环境材料所-2 10-502 10-54 10-56 10-58 10-50.0001-5005010015050556065707580Load (mN)S (N/m)Load (mN)Contact Stiffness (N/m)Quasi-static Displa
23、cement (nm)Surface Contact Determination（表面探测）（表面探测）(Critically important for very thin films and soft materials)1、拟合函数，外推法确定零点、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、载荷或接触刚度的首次增加为零点Point of Contact ?中山大学环境材料所中山大学环境材料所AccuTip Berkovich Diamond TipsThe sharper the tip, the shallower an indent can be made to g
24、ive reliable hardness valuesDeep indent requiredShallow indent possibleIdeal tip中山大学环境材料所中山大学环境材料所AccuTip Berkovich Diamond TipsOld diamond tips Face angles（中心线与面的夹角） fairly consistent, but not known with any precision Tip radius typically 100 150 nmNew AccuTip Berkovich diamond tips Face angles kno
25、wn to 0.025 Tip radius 50 nm (typically 40 nm) before 2007 Tip radius 20 nm since 2008中山大学环境材料所中山大学环境材料所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 significant eff
26、ect of the film in the measurement中山大学环境材料所中山大学环境材料所Tip SharpnessSharp tipDull tipHardnessDepth of penetrationA sharp tip is required for making hardness measurements at very shallow indentation depths中山大学环境材料所中山大学环境材料所AccuTip Berkovich diamond TipTwo different DLC films, both 20 nm thick same films
27、 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中山大学环境材料所中山大学环境材料所Hard coating & surface modification中山大学环境材料所中山大学环境材料所Ion Implantation of Hard Chrome Pl
28、ating0510152002004006008001000Control 3/4/97PSII 3/4/97Control 3/5/97PSII 3/5/97Control 3/10/97PSII 3/10/97Hardness (GPa)Displacement (nm)中山大学环境材料所中山大学环境材料所TiC Coated Ball Bearings中山大学环境材料所中山大学环境材料所Optical Coatings - Siloxane on PC012345678050100150200250300Average Hardness (GPa)Displacement (nm)中山大
29、学环境材料所中山大学环境材料所Micro Electronic Machines (MEMS)The Nano Indenter XP makes a great MEMS Tester LFM micro tensile Double dog bone micro-tensile中山大学环境材料所中山大学环境材料所Raytheon RF MEMS SwitchYoungs modulus of membrane very important for switch performanceNeed to deflect membrane without complicated stress st
30、atesPublished by H.D. Espinosa, M. Fischer, Northwestern University and E. Herbert, W.C. Oliver, MTS Nano Instruments中山大学环境材料所中山大学环境材料所Diamond Tip GeometryMore acute diamond wedgeObtuse angle diamond wedge will limit amount of vertical displacement possible中山大学环境材料所中山大学环境材料所Membrane Deflection（膜偏离）（
31、膜偏离） 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中山大学环境材料所中山大学环境材料所
32、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 by H.D. Espinosa
33、, M. Fischer, Northwestern University and E. Herbert, W.C. Oliver, MTS Nano Instruments中山大学环境材料所中山大学环境材料所AccuTip Diamond TipsScratch Testing划痕测试划痕测试中山大学环境材料所中山大学环境材料所Scratch Friction CoefficientFNFTstindentermaterialMotion of indenterScratch friction coefficient划痕摩擦系数Actual friction coefficient实际摩擦系
34、数NTsFFf staf(Indenter geometry dependent)(same with Berkovich and Cube Corner)中山大学环境材料所中山大学环境材料所Scratch testing with a BerkovichLow angle of attack（小接触角）Plastic deformation（塑性变形）Face forward面划入Edge forward（棱划入）中山大学环境材料所中山大学环境材料所-1200-1000-800-600-400-200020040060080020304050607080profile distance (u
35、m)profile height (nm)ahbp中山大学环境材料所中山大学环境材料所Fracture Initiation: Critical Load Measurement050010001500200025000100200300400500600700scratch distance (um)indenter penetration (nm)Pc= 2.5 mNhc= 1500 nmPenetration under loadResidual scratch depth中山大学环境材料所中山大学环境材料所Study of fracture damage mechanisms（破裂损坏
36、机（破裂损坏机理）理）Cube Corner indenterChipping processImportant parameters: Indenter geometry Load for fracture initiation中山大学环境材料所中山大学环境材料所-600-400-2000200-25-15-551525profile distance (um)profile height (nm)30 minafter 15 daysafter 8 h 40oCBerkovich with face forwardVisco-Plastic Recovery of ScratchesTim
37、e and Temperature DependenceAutomotive paint polymer clear coat中山大学环境材料所中山大学环境材料所3D Profilometry & Nanopositioning100 x 100 um travel Resolution: 2nm Reproducibility: 2nm Linearity error:500um Resolution : 0.1nm Closed Loop中山大学环境材料所中山大学环境材料所TopoSurface 3D Profilometry中山大学环境材料所中山大学环境材料所Acquisition of
38、 3D Topographic data中山大学环境材料所中山大学环境材料所Acquisition of 3D Topographic dataTestWorks DataTopoSurf 3D中山大学环境材料所中山大学环境材料所Acquisition of 3D Topographic dataInputs in the TestWorks Method Length of scan Number of points per scan Distance between scans Number of scans Orientation of the scansSet the start location with microscope just like an indent中山大学环境材料所中山大学环境材料所Nanopositioning Capability中山大学环境材料所中山大学环境材料所Nanopositioning Capability中山大学环境材料所中山大学环境材料所Nanopositioning Capability中山大学环境材料所中山大学环境材料所
