作者:标准资料网 时间:2024-05-20 08:26:00   浏览:8719   来源:标准资料网

【英文标准名称】:StandardPracticeforThermalDiffusivitybytheFlashMethod
【原文标准名称】:利用闪蒸法测定热扩散率的标准操作规程
【标准号】:ASTME2585-2009
【标准状态】:现行
【国别】:
【发布日期】:2009
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:E37.05
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:闪蒸法;红外探测器;内部热电偶;比热容;导热性;热扩散系数;瞬变温度测量;导热性/热传导率;瞬变温度;热分析(TA)
【英文主题词】:flashmethod;infrareddetectors;intrinsicthermocouples;specificheatcapacity;thermalconductivity;thermaldiffusivity;transienttemperaturemeasurements;Intrinsicthermocouples;Thermalanalysis(TA);Thermalconductance/conductivity;Therm
【摘要】:Thermaldiffusivityisanimportantproperty,requiredforsuchpurposesundertransientheatflowconditions,suchasdesignapplications,determinationofsafeoperatingtemperature,processcontrol,andqualityassurance.Theflashmethodisusedtomeasurevaluesofthermaldiffusivity,x03B1;,ofawiderangeofsolidmaterials.Itisparticularlyadvantageousbecauseofsimplespecimengeometry,smallspecimensizerequirements,rapidityofmeasurementandeaseofhandling.Undercertainstrictconditions,specificheatcapacityofahomogeneousisotropicopaquesolidsamplecanbedeterminedwhenthemethodisusedinaquantitativefashion(seeE1461,Appendix1).Thermaldiffusivityresults,togetherwithrelatedvaluesofspecificheatcapacity(Cp)anddensity(x03C1;)values,canbeusedinmanycasestoderivethermalconductivity(x03BB;),accordingtotherelationship:1.1Thispracticecoverspracticaldetailsassociatedwiththedeterminationofthethermaldiffusivityofprimarilyhomogeneousisotropicsolidmaterials.Thermaldiffusivityvaluesrangingfrom10-7to10-3m2/sarereadilymeasurablebythisfromabout75to2800K.1.2ThispracticeisadjuncttoE1461.1.3Thispracticeisapplicabletothemeasurementsperformedonmaterialsopaquetothespectrumoftheenergypulse,butwithspecialprecautionscanbeusedonfullyorpartiallytransparentmaterials.1.4Thispracticeisintendedtoallowawidevarietyofapparatusdesigns.Itisnotpracticalinadocumentofthistypetoestablishdetailsofconstructionandprocedurestocoverallcontingenciesthatmightofferdifficultiestoapersonwithoutpertinenttechnicalknowledge,ortostoporrestrictresearchanddevelopmentforimprovementsinthebasictechnique.Thispracticeprovidesguidelinesfortheconstructionprinciples,preferredembodimentsandoperatingparametersforthistypeofinstruments.1.5Thispracticeisapplicabletothemeasurementsperformedonessentiallyfullydensematerials;however,insomecasesithasshowntoproduceacceptableresultswhenusedwithporousspecimens.Sincethemagnitudeofporosity,poreshapes,andparametersofporedistributioninfluencethebehaviorofthethermaldiffusivity,extremecautionmustbeexercisedwhenanalyzingdata.Specialcautionisadvisedwhenotherproperties,suchasthermalconductivity,arederivedfromthermaldiffusivityobtainedbythismethod.1.6Theflashcanbeconsideredanabsolute(orprimary)methodofmeasurement,sincenoreferencematerialsarerequired.Itisadvisabletouseonlyreferencematerialstoverifytheperformanceoftheinstrumentused.1.7Thismethodisapplicableonlyforhomogeneoussolidmaterials,inthestrictestsense;however,insomecasesithasbeenshowntoproducedatafoundtobeusefulincertainapplications:1.7.1TestingofCompositeMaterials8212;Whensubstantialnon-homogeneityandanisotropyispresentinamaterial,thethermaldiffusivitydataobtainedwiththismethodmaybesubstantiallyinerror.Nevertheless,suchdata,whileusuallylackingabsoluteaccuracy,maybeusefulincomparingmaterialsofsimilarstructure.Extremecautionmustbeexercisedwhenrelatedproperties,suchasthermalconductivity,arederived,ascompositematerials,forexample,mayhaveheatflowpatternssubstantiallydifferentthanuniaxial.Incaseswherethepartic......
【中国标准分类号】:A42
【国际标准分类号】:17_200_10
【页数】:10P.;A4
【正文语种】: