1、Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityEvaluation of Fracture Toughness of MaterialsUsing Instrumented Indentation Technique:Ductile/Brittle Fracture Models2013.08.30.Won Je JoContents Introduction Indentation Fracture Toughness Models-Brittle fra
2、cture model-Ductile fracture model Verification of the Models-Comparison between fracture test results and IIT results-Applications at low temperature Basic concept of indentation fracture toughnessFast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityFracture t
3、estCrack propagation and fractureIndenterIITNo crack and no fractureIssue of indentation fracture toughnessWhat is a correlation between fracture test and IIT?In the case of metals,2Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityConstraint effectahead of
4、a crack tipPlastic region constrained by elastic regionbeneath an indenterSimilar constraint effectSimilar constraint effect3Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityR=250mIndenterMaterial:API X70loadingConstraint effect2.1 3.22.3 3.0Triaxiality of
5、crack tip Triaxiality of indentationSENBSENBIndentationIndentation4Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityIndentation fracture toughnessAnalogous situation5Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&Reliabilit
6、yEnergy concept=Required energy for crack propagationEquivalent fracture energy in IndentationAnalysis of indentation process6Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityIndentation processFormation of a plastic zone to the surface7Fast&Precise Solutio
7、nsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityFormation of a fully-developed plastic zone (c/a is constant)Expansion of plastic zone(c/a increase)cacaAssumptionOnset of formation of a fully-developed plastic zone=Maximum strain energy beneath the indenter Formation of equiv
8、alent fracture energyh*8c/ahh*Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityBrittle materialsDuctile materialsFracturesurfaceDeformationRelatively little or no deformationLarge plastic deformationCriterionStress controlledcritical fracture stress at the
9、crack tip(sf)Strain controlledcritical fracture strain at the crack tip(ef)Formation offracture energyWhen stress reached critical fracture stressWhen strain reached critical fracture strainFracture Behavior9Brittle Fracture ModelDuctile Fracture ModelFast&Precise SolutionsFast&Precise Solutions for
10、 Quality&Reliability for Quality&ReliabilityBrittle Fracture Model10Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityCriterion11Critical indentation depth(h*)rrCritical stress(pressure)at h*CriterionFast&Precise SolutionsFast&Precise Solutions for Quality&R
11、eliability for Quality&ReliabilityAssumptionOnset of formation to a fully-developed plastic zone=Formation of Equivalent fracture energy12Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityApplication of indentation theoriesStep 1 Yielding right outside the c
12、ontact areaFormation of a plastic zone to the surfaceStep 2Expansion of the plastic zoneFormation of fully-developed plastic zonecah*13Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityHertz elastic contact theoryStress outside the contact area(r a)vWhen a r
13、adial stress at the edge of the contact area(r=a)satisfied yielding criterion By Von Mises yield criterion14Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityExpanding cavity model(E-P theory)Stress within plastic zone(a r c)vChange of the core pressure(r=a)
14、until forming the fully-developed plastic zoneby K.E.Puttick(1977)15coreFast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityCriterion of equivalent fracture energyStep 1The total pressure required for equivalent fracture energy,Step 216Fast&Precise SolutionsFa
15、st&Precise Solutions for Quality&Reliability for Quality&ReliabilityFracture toughness for brittle materiall Pm-h curvel Indentation load-depth curve-Mean contact pressure at each unloading depth(1)Indentation testing(6)Indentation fracture toughness(KJC)(2)Measuring ys&Determining Pmc-ys from analy
16、zing L-h curve(3)Fitting Pm-h curve-(4)Determining h*-Inserting determined Pmc into Pm-h curve(5)Equivalent fracture energy until h*17Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityDuctile Fracture Model18Fast&Precise SolutionsFast&Precise Solutions for Q
17、uality&Reliability for Quality&ReliabilityCriterion19Critical indentation depth(h*)rrCritical strain at h*CriterionFast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&Reliability20Critical strain at h*CriterionAbsorbed strain energy until fracture strain=Toughness(tensil
18、e energy)Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityAssumptionElastic energy released due to the crack growth is equal to the amount of plastic work ahead of the crack tip.Peel and Frosyth,1973Plastic work done per unit areaPlastic work done per unit
19、arear:the radius of the plastic zoneUT:plastic work done per unit volumeFor small scale yielding,Elastic energy released per unit areaElastic energy released per unit area21Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityPlastic workMechanical metallurgy,G
20、E.DieterPlastic work done =Area Under the Stress-Strain CurvesR:flow stressef :engineering fracture strain22Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityMechanical parametersEstimation from indentation parametersPlastic zone sizeFracture strainMeasured
21、 parametersElastic propertiesvs.Plastic propertiesFunction of uniform strain Yield strength Ultimate tensile strength Elastic modulus Poissons ratio,n=0.3Fracture toughnessrcefMeasured by indentation test23Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityPl
22、astic zone size,rcPPlastic flowElastic constraintPlastic zoneA balance between plastic flowand elastic constraintDominant elastic constraintDominant plastic flow Small PZSLarge PZSResilienceResilienceFracture strain,efExperimental relation betweentrue uniform strain and engineering fracture strain,2
23、4Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityPlastic zone sizeFracture strainMeasured parametersFracture toughnessFracture toughness for ductile material25Contents Introduction Indentation Fracture Toughness Models-Brittle fracture model-Ductile fractu
24、re model Verification of the Models-Comparison between fracture test results and IIT results-Applications at low temperature-Basic concept of indentation fracture toughnessFast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityList of the tested materialsMaterial
25、Tensile test resultsKJC from J-test resultsE YSUTSnefUniform strainSpecimen thicknessJCKJC(Avg.)Stdev.MPammkJ/m2MPam1Carbonsteel(structure)SCM4 207000723.349 994.488 0.130 0.168 0.066 843.68106.160.342SK3 207000315.100 706.527 0.263 0.356 0.180 834.7688.8610.823SKS3 207000434.900 755.502 0.218 0.314
26、 0.160 860.60118.175.784SKH51 207000294.850 784.372 0.259 0.171 0.117 814.5759.754.365SKD11 207000342.800 807.687 0.255 0.118 0.099 840.5298.376.836SUJ2 207000404.300 821.659 0.240 0.333 0.161 854.38113.8713.037S45C207000338.473 727.805 0.269 0.273 0.147 15144.61181.325.078SCM21207000288.752 579.349
27、 0.223 0.298 0.142 15339.98281.3712.039SS400207000259.399 497.034 0.238 0.380 0.182 20423.05310.210.0510SKD61207000377.415 765.815 0.235 0.310 0.142 20571.61360.583.0211Low Temp.pipelineA106207000304.523 583.154 0.217 0.303 0.158 13.5304.56263.0313.5812Cr-Mo(boiler tube)A387 G22207000519.350 689.020
28、 0.142 0.249 0.085 16518.58343.1418.1213API(petroleumpipeline)X65207000466.913 650.875 0.169 0.350 0.149 14372.91291.187.9914X100207000598.560 918.072 0.141 0.251 0.089 19548.24352.8019.0715X120207000745.863 1022.969 0.130 0.200 0.054 16687.95395.529.2516StainlesssteelSUS403207000335.277 671.527 0.2
29、12 0.360 0.154 13332.40274.9810.9217SUS420J2207000398.468 797.689 0.207 0.290 0.124 8103.87155.2910.5818SUS440 207000329.900 820.767 0.256 0.215 0.118 826.3385.020.1219SUS304207000285.685 1138.378 0.359 0.774 0.493 20537.13349.2717.0520SUS304L207000258.816 1164.728 0.402 0.654 0.427 20666.29389.2111
30、0421SUS347207000244.863 999.489 0.369 0.644 0.416 23591.39366.746.4322SUS321207000252.402 1039.966 0.373 0.724 0.471 22499.02336.912.6723Al-alloyAl2024 70000459.100 669.399 0.152 0.165 0.128 848.2064.077.5324Al7075 70000517.700 621.813 0.080 0.136 0.050 817.2436.969.1025Cu-alloyC62400120000433.206
31、842.945 0.259-0.066 94.8325.610.35 26InCu120000160.025 480.855 0.328 0.483 0.371 17187.25156.8515.1527Ni-alloyAlloy20207000348.337 762.178 0.235 0.379 0.207 17453.21321.08-28Ti-alloyTi-6Al-4V110000937.128 1099.815 0.080-0.086 990.16 113.62 11.43 29Ti-6Al-6V-2Sn1100001009.230 1172.560 0.076-0.105 939
32、00 72.24 3.1230Ti-5Al-2.5Sn110000885.569 1038.013 0.066-0.096 961.56 86.63 5.73 31Ti-10Al-2Fe-3Al1100001163.318 1257.332 0.096-0.027 994.07 96.5917.33 Comparing between conventional fracture toughness results andComparing between conventional fracture toughness results and instrumented indentation
33、testing results for 31 metals instrumented indentation testing results for 31 metals27Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityTesting conditions28IndenterIndenter radiusControlling methodWC spherical indenter250 umMax.depth controlEquipmentAIS Syst
34、emMax.indentationdepth150 umZero index0.06 kgfSurface roughnessSand paper#2000Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&Reliability+20%-20%KJC ResultsKJC from IIT(MPam)KJC from Jc(MPam)29BrittlefracturemodelDuctilefracturemodelFast&Precise SolutionsFast&Precise
35、 Solutions for Quality&Reliability for Quality&ReliabilityKJC ResultsBrittle materialsBrittle materialsDuctile materialsDuctile materialsDuctileMaterial KJC from J-testKJC from IITKJC(Avg.)Stdev.KJC(Avg.)Stdev.MPamMPamCarbonsteel(structure)SCM21281.3712.03256.504.73SS400310.210.05235.4515.18SKD61360
36、583.02316.4710.96Low Temp.PipelineA106263.0313.58242.6011.01Cr-Mo(boiler tube)A387 G22343.1418.12273.6311.18API(petroleumpipeline)X65291.187.99273.336.03X100352.8019.07330.7513.57X120395.529.25448.105.54StainlesssteelSUS403274.9810.92251.263.86SUS304349.2717.05373.3821.34SUS304L389.2111.04398.4733.
37、71SUS347366.746.43326.2811.94SUS321336.912.67324.2215.87Ni-alloyAlloy20321.08-292.885.53BrittleMaterialKJC from J-testKJC from IITKJC(Avg.)Stdev.KJC(Avg.)Stdev.MPamMPamCarbonsteel(structure)SCM4 106.160.3490.876.62SK3 88.8610.8289.963.49SKS3 118.175.78110.683.10SKH51 59.754.3690.1310.99SKD11 98.376.
38、8389.827.96SUJ2 113.8713.03103.1914.21S45C181.325.07165.809.49StainlesssteelSUS420J2155.2910.58156.817.94SUS440 85.020.1294.779.75Al-alloyAl2024 64.077.5352.064.56Al7075 36.969.1043.873.30Cu-alloyC6240025.610.35 16.82-InCu156.8515.15160.376.06Ti-alloyTi-6Al-4V113.62 11.43 108.3315.47Ti-6Al-6V-2Sn72.
39、24 3.1250.076.96Ti-5Al-2.5Sn86.63 5.73 92.2110.47Ti-10Al-2Fe-3Al96.5917.33 75.1915.1430Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityLow Temperature Chamber System Evaluation of fracture toughness with changing temperature Measurement of fracture toughne
40、ss at low temperature Analysis of subzero temperature using ASTM E1921Application Chamber Size(WxDxH)410 x 300 x 160(mm)Cooling elementLiquid nitrogen Circumstances of testVacuum,isolation Minimum Temp.-160 oC(-256 oF)Cooling rate 40 oC/min (40 oF/min)Specifications31Chamber ControllerAIS SystemCham
41、berFast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityCharpy V-notch sample Relation between CVN results and IIT toughness results-Material:2.25Cr1MoV steel(Weldments)-Test temperature;RT and-29oCApplications at low temperature32Fast&Precise SolutionsFast&Pre
42、cise Solutions for Quality&Reliability for Quality&ReliabilityApplications at low temperature-Master Curve:KJC from IIT:KJC from J-Test Specimen information and testing conditionsChemical composition(wt.%)C Si Mn P S Ni 0.21 0.24 1.36 0.007 0.002 0.92 Cr Mo Al Cu V 0.21 0.49 0.022 0.03 0.005 Chemica
43、l composition of specimenMaterialSA508-3,ID:GS880SpecimenCompact tension and precracked CVNUseNuclear reactor pressure vesselTemperature range(about10 Interval)-110-20Fracture toughness testingASTM E192033Fast&Precise SolutionsFast&Precise Solutions for Quality&Reliability for Quality&ReliabilityApp
44、lications at low temperature-Master Curve:KJC from IIT:KJC from J-TestReference:Bong-Sang Lee,Min-Chul Kim,Maan-Won Kim,Ji-Hyun Yoon,Jun-Hwa Hong,“Master curve techniques to evaluate an irradiation embrittlement of nuclear reactor pressure vessels for a long-term operation”,International Journal of
45、Pressure Vessels and Piping 85(2008)593599 Specimen information and testing conditionsChemical composition(wt.%)C Si Mn P S Ni 0.21 0.24 1.36 0.007 0.002 0.92 Cr Mo Al Cu V 0.21 0.49 0.022 0.03 0.005 Chemical composition of specimenMaterialSA508-3,ID:CS50SpecimenCompact tension and precracked CVNUseNuclear reactor pressure vesselTemperature range(about10 Interval)-110-20Fracture toughness testingASTM E192034Thank you for your attention!
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