《ebsd數(shù)據(jù)分析》ppt課件-文庫吧
2025-04-27 13:59 本頁面
【正文】 e(5ox5ox5o)?Fastcalculation?Suitableformosttexturestrengthsbutnotweaktexturesifthenumberofgrainsissmall(considerthenumberofdatapointspercellrequiredtoachievereasonablylownoise)ContinuousODF:?GeneralizedSphericalHarmonicFunctions:Rankdefinesthe“resolution”ofthefunction?EquivalenttoaFouriertransform?Calculationtimerisessteeplywithranknumber(32isaneffectivemaximum)?Timeintensive?Mostlyappropriateforweakertextures?SomesmoothingisinherentPlotting Orientation Distributions? Onemustselectthetypesofdatavisualizationdesired?Polefiguresshowthedistribution of specificcrystal planes .samplereferenceframe?ForthegenerationofmorethanonePF,theyneedtobeaddedoneatatime.InversePoleFiguresareused to illustrate whichcrystal plane normals areparallel to sampledirections (generally RD,TDamp。ND)? The indices enteredrepresent which samplereference frame plane isbeingconsidered:100,010and001aretypicalchoices?MultipleplanesalsoneedtobeenteredoneatatimeEulerspaceplotshowsthedistributionofintensityasafunctionoftheEulerangles?Usedtovisualizepocketsoftextureaswellas“fiber”textures?ResolutiondefineshowmanyslicesarepossibleintheplotTypes of ODF/Pole Figure/ Inverse PF PlotsChoose textureand desired plottypeUse to addmultiple plots tothesameimageNB: a more prehensive discussion of reference frames is given laterTheAverage Orientation ofthepixelsinagrainisgivenbythisequation:RD10000orientationsneartotheBrassponent:represented?bya{111}polefigure?and,inthepleteEulerspacetoshowthe24equivalentsresultingfromapplicationofcubiccrystalsymmetry{111}Preparation of the data for analysisi=1,24Courtesy of N. BozzoloVerysimple,n’estcepas?However,thereisaproblem...Asaconsequenceofthecrystalsymmetry,thereareseveralequivalentorientations.Thisexampleillustratesthepoint:ChoJH,RollettADandOhKH(2022)Determinationofameanorientationinelectronbackscatterdiffractionmeasurements,Metall. Mater. Trans.36A342738?1=0176。 ?1=5176。 ?1=10176。 ?1=15176。...max = ...Parameters for texture analysis Courtesy of N. Bozzolomax = 16x16x83176。225176。max = 32x32x168176。225176。max = Resolution 32x32x16Gaussian 3176。Lmax 22BinSize 5176。Effect of the binning resolution Effect of the width of the GaussianParameters for texture analysis Courtesy of N. Bozzolomax = Lmax = 16max = Lmax = 22Effect of the maximum rank in the series expansion, Lmaxmax = Lmax = 5max = Lmax = 8max = Lmax = 34Resolution 32x32x16Gaussian 3176。Lmax 22BinSize 5176。Courtesy of N. Bozzolomax = 31 !Same,with10176。binning :Direct Methodmax = Ineffecttheharmonicmethodgivessome”smoothing.Withoutthis,acoarsebinningof,say,10176。,producesavery“l(fā)umpy”result.?1=5176。Courtesy of N. Bozzolo?0= 8176。 at {0 35 30}80000 grains at {0 35 30} at {0 35 25} at {0 30 25} at {15 30 30}2022 grains at {5 30 15} at {345 35 50} at {5 35 50}16000 grains at {0 35 30} at {0 35 30} at {5 35 35} at {5 30 40}Gaussienne de ?0= 4176。Triclinicsamplesymmetry?0= 4176。?0= 8176。Statistical Aspects ?Numberofgrainsmeasured?WidthoftheGaussian(and/orLmax)?InfluenceofthesamplesymmetryZirconium,equiaxedSectionsthrutheODatconstant?1(Lmax=34)Texture=distributionoforientations?Problemofsampling!OrthorhombicsamplesymmetryCourtesy of N. BozzoloSingleEBSDmap(1mm2) Multiplemaps,differentlocations(total=1mm2)RDTD ND{} ()asymmetryofintensityHomogeneity/heterogeneityofthespecimen...equiaxedTiNotjustthenumberofgrainsmustbeconsideredbutalsotheirspatialdistribution:Statistical Aspects Courtesy of N. BozzoloTexture – Microstructure CouplingExample:partialtextureofpopulationsofgrainsidentifiedbyagrainsizecriterion(zirconiumattheendofrecrystallization)partialtextureofthelargest grains Partialtextureofthesmallest grainsImportantfortextureevolutionduringgraingrowth:thelargegrainsgrowattheexpenseofthesmallgrains.Sincethelargegrainshaveadifferenttexture,theoveralltexturealsochang
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