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【英文标准名称】:StandardTestMethodforCreep-FatigueCrackGrowthTesting
【原文标准名称】:蠕变—疲劳龟裂增大试验的标准试验方法
【标准号】:ASTME2760-2010
【标准状态】:现行
【国别】:美国
【发布日期】:2010
【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】:E08.06
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:compactspecimens;cracks;crackgrowth;creep;fatigue;metals
【摘要】:Creep-fatiguecrackgrowthtestingistypicallyperformedatelevatedtemperaturesoverarangeoffrequenciesandhold-timesandinvolvesthesequentialorsimultaneousapplicationoftheloadingconditionsnecessarytogeneratecracktipcyclicdeformation/damageenhancedbycreepdeformation/damageorviceversa.Unlesssuchtestsareperformedinvacuumoraninertenvironment,oxidationcanalsoberesponsibleforimportantinteractioneffectsrelatingtodamageaccumulation.Thepurposeofcreep-fatiguecrackgrowthtestscanbetodeterminematerialpropertydatafor(a)assessmentinputdataforthedamageconditionanalysisofengineeringstructuresoperatingatelevatedtemperatures,(b)materialcharacterization,or(c)developmentandverificationofrulesfordesignandlifeassessmentofhigh-temperaturecomponentssubjecttocyclicservicewithlowfrequenciesorwithperiodsofsteadyoperation,oracombinationthereof.Ineverycase,itisadvisabletohavecomplementarycontinuouscyclingfatiguedata(gatheredatthesameloading/unloadingrate),creepcrackgrowthdataforthesamematerialandtesttemperature(s)asperTestMethodE1457,andcreep-fatiguecrackformationdataasperTestMethodE2714.Aggressiveenvironmentsathightemperaturescansignificantlyaffectthecreep-fatiguecrackgrowthbehavior.Attentionmustbegiventotheproperselectionandcontroloftemperatureandenvironmentinresearchstudiesandingenerationofdesigndata.Resultsfromthistestmethodcanbeusedasfollows:Establishmaterialselectioncriteriaandinspectionrequirementsfordamagetolerantapplicationswherecyclicloadingatelevatedtemperatureispresent.Establish,inquantitativeterms,theindividualandcombinedeffectsofmetallurgical,fabrication,operatingtemperature,andloadingvariablesoncreep-fatiguecrackgrowthlife.Theresultsobtainedfromthistestmethodaredesignedforcrackdominantregimesofcreep-fatiguefailureandshouldnotbeappliedtocracksinstructureswithwide-spreadcreepdamage.Localizeddamageinasmallzonearoundthecracktipispermissible,butnotinazonethatiscomparableinsizetothecracksizeortheremainingligamentsize.1.1Thistestmethodcoversthedeterminationofcreep-fatiguecrackgrowthpropertiesofnominallyhomogeneousmaterialsbyuseofpre-crackedcompacttype,C(T),testspecimenssubjectedtouniaxialcyclicforces.Itconcernsfatiguecyclingwithsufficientlylongloading/unloadingratesorhold-times,orboth,tocausecreepdeformationatthecracktipandthecreepdeformationberesponsibleforenhancedcrackgrowthperloadingcycle.Itisintendedasaguideforcreep-fatiguetestingperformedinsupportofsuchactivitiesasmaterialsresearchanddevelopment,mechanicaldesign,processandqualitycontrol,productperformance,andfailureanalysis.Therefore,thismethodrequirestestingofatleasttwospecimensthatyieldoverlappingcrackgrowthratedata.Thecyclicconditionsresponsibleforcreep-fatiguedeformationandenhancedcrackgrowthvarywithmaterialandwithtemperatureforagivenmaterial.Theeffectsofenvironmentsuchastime-dependentoxidationinenhancingthecrackgrowthratesareassumedtobeincludedinthetestresults;itisthusessentialtoconducttestinginanenvironmentthatisrepresentativeoftheintendedapplication.1.2Twotypesofcrackgrowthmechanismsareobservedduringcreep/fatiguetests:(1)time-dependentintergranularcreepand(2)cycledependenttransgranularfatigu......
【中国标准分类号】:H22
【国际标准分类号】:77_040_10
【页数】:19P.;A4
【正文语种】:英语