【英文标准名称】:StandardTestMethodforFlexuralStrengthofAdvancedCeramicsatAmbientTemperature
【原文标准名称】:环境温度下高级陶瓷抗弯强度标准试验方法
【标准号】:ASTMC1161-2002c(2008)e1
【标准状态】:现行
【国别】:美国
【发布日期】:2002
【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】:C28.01
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:advancedceramics;flexuralstrength;four-pointflexure;three-pointflexure;Advancedceramics;Flexuraltesting--ceramics;Four-pointloadedbeammethod;Fracturetesting--advancedceramics;Loadingtests--ceramics;Thermometers;Three-pointloadin
【摘要】:Thistestmethodmaybeusedformaterialdevelopment,qualitycontrol,characterization,anddesigndatagenerationpurposes.Thistestmethodisintendedtobeusedwithceramicswhosestrengthis50MPa(~7ksi)orgreater.Theflexurestressiscomputedbasedonsimplebeamtheorywithassumptionsthatthematerialisisotropicandhomogeneous,themoduliofelasticityintensionandcompressionareidentical,andthematerialislinearlyelastic.Theaveragegrainsizeshouldbenogreaterthanonefiftiethofthebeamthickness.Thehomogeneityandisotropyassumptioninthestandardruleouttheuseofthistestforcontinuousfiber-reinforcedceramics.Flexuralstrengthofagroupoftestspecimensisinfluencedbyseveralparametersassociatedwiththetestprocedure.Suchfactorsincludetheloadingrate,testenvironment,specimensize,specimenpreparation,andtestfixtures.Specimensizesandfixtureswerechosentoprovideabalancebetweenpracticalconfigurationsandresultingerrors,asdiscussedinMIL-STD1942(MR)andRefs(1)and(2).SpecificfixtureandspecimenconfigurationsweredesignatedinordertopermitreadycomparisonofdatawithouttheneedforWeibull-sizescaling.Theflexuralstrengthofaceramicmaterialisdependentonbothitsinherentresistancetofractureandthesizeandseverityofflaws.Variationsinthesecauseanaturalscatterintestresultsforasampleoftestspecimens.Fractographicanalysisoffracturesurfaces,althoughbeyondthescopeofthisstandard,ishighlyrecommendedforallpurposes,especiallyifthedatawillbeusedfordesignasdiscussedinMIL-STD-1942(MR)andRefs(2x2013;5)andPracticesC1322andC1239.Thethree-pointtestconfigurationexposesonlyaverysmallportionofthespecimentothemaximumstress.Therefore,three-pointflexuralstrengthsarelikelytobemuchgreaterthanfour-pointflexuralstrengths.Three-pointflexurehassomeadvantages.Itusessimplertestfixtures,itiseasiertoadapttohightemperatureandfracturetoughnesstesting,anditissometimeshelpfulinWeibullstatisticalstudies.However,four-pointflexureispreferredandrecommendedformostcharacterizationpurposes.Thismethoddeterminestheflexuralstrengthatambienttemperatureandenvironmentalconditions.Theflexuralstrengthunderambientconditionsmayormaynotnecessarilybetheinertflexuralstrength.Note78212;timedependenteffectsmaybeminimizedthroughtheuseofinerttestingatmospheresuchasdrynitrogengas,oil,orvacuum.Alternatively,testingratesfasterthanspecifiedinthisstandardmaybeused.Oxideceramics,glasses,andceramicscontainingboundaryphaseglassaresusceptibletoslowcrackgrowthevenatroomtemperature.Water,eitherintheformofliquidorashumidityinair,canhaveasignificanteffect,evenattheratesspecifiedinthisstandard.Ontheotherhand,manyceramicssuchasboroncarbide,siliconcarbide,aluminumnitrideandmanysiliconnitrideshavenosensitivitytoslowcrackgrowthatroomtemperatureandtheflexuralstrengthinlaboratoryambientconditionsistheinertflexuralstrength.1.1Thistestmethodcoversthedeterminationofflexuralstrengthofadvancedceramicmaterialsatambienttemperature.Four-pointx2013;x00BC;pointandthree-pointloadingswithprescribedspansarethestandard.Rectangularspecimensofprescribedcross-sectionsizesareusedwithspecifiedfeaturesinprescribedspecimen-fixturecombinations.1.2ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgivenin......
【中国标准分类号】:Q32
【国际标准分类号】:81_060_20
【页数】:16P.;A4
【正文语种】:英语