dimensional stability of advanced materials：先进材料的尺寸稳定性

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1、DIMENSIONALSTABILITYOFADVANCEDMATERIALSErnestG.WolffPrecisionMeasurements&InstrumentsCorporationCorvallis,OR97333ABSTRACTAllmaterialsaltertheirshapeandsizeinresponsetochangesinappliedandinternalloadsandenvironmentalconditions,includingtime.Seriousconsequencesmayoccurformanyapplications,e

2、speciallyintheaerospaceandelectronicsfields.Controlofdimensionalinstabilityismorecomplexforcompositematerials,componentsandstructuresbecausetheresponseofeachconstituentismodifiedbyalltheothers.Trendstomorestringentdesignsandtheadventofnewmaterialsfurthercomplicatethepredictionofdimension

3、albehavior.Developmentsinthedesign,measurementandassessmentofdimensionalstabilityarereviewed,withemphasisonfurtherresearchandnewapplications.KEYWORDS:Dimensionalstability,testing/evaluation,opticaltesting1.INTRODUCTION1.1DimensionalStabilityDimensionalstabilityisageneralpropertyofamateri

4、al,componentorstructurewhichenablesittomaintainitsshape,size,oranydimension.Allcomponentsandstructureshavedimensionalstabilityrequirements,butoftenstrengthproperties(e.g.tensilestrengthorimpactstrength)orlifetime(e.g.fatiguelife)maybemoreimportant.Wefirstreviewrelevantmaterialsandtheirdi

5、mensionalresponsetochangesinloadsorstressandthentheirresponsetoenvironmentalchanges,namelytemperature,chemical,radiationandelectromagneticfieldsandtime(1).Amorecomplexsituationariseswhenweconsiderthattheeffectofcombinedloadsandtheirinteractions,includingcausesandeffectsofinternaldamagesu

6、chasmicrocracking.1.2DimensionalControlTolerancesprescribedforsuccessfuldeploymentmustberelatedtotheinteractionsofthemicromechanicalandthermophysicalpropertiesofthematerialsinvolvedinfabricationaswellasthoseusedinconstructioncombinationsandattachments.ExamplesincludetheCTE(α)ofthemoldmat

7、erial(asinvacuumassistedresintransfermolding)andthecuringandpostcuringofaresinpartaftermanufacture.Residualstressescausedbythemanufacturingprocesscontributetosubsequentdimensionalchangesofthecomponent.Thedesignofacomponentorstructuremustconsiderpotentialchangesinsizeorsha