【英文标准名称】:StandardPracticeforFractographicAnalysisofFractureMirrorSizesinCeramicsandGlasses
【原文标准名称】:陶瓷和玻璃中的断裂镜面尺寸的断裂面显微镜图像分析的标准实施规程
【标准号】:ASTMC1678-2010
【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】:C28.03
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:ceramics;fractography;fracturemirror;fracturestrength;fracturestress;fracturesurface;glasses;hackle;microscope;mist;origin;residualstresses;Ceramicware;Fracturemirrors;Fracturetesting--glass;Glassware
【摘要】:Fracturemirrorsizeanalysisisapowerfultoolforanalyzingglassandceramicfractures.FracturemirrorsaretelltalefractographicmarkingsinbrittlematerialsthatsurroundafractureoriginasdiscussedinPracticesC1256andC1322.Fig.1showsaschematicwithkeyfeaturesidentified.Fig.2showsanexampleinglass.Thefracturemirrorregionisverysmoothandhighlyreflectiveinglasses,hencethenamex201C;fracturemirror.x201D;Infact,highmagnificationmicroscopyrevealsthat,evenwithinthemirrorregioninglasses,thereareveryfinefeaturesandescalatingroughnessasthecrackadvancesawayfromtheorigin.Thesearesubmicrometerinsizeandhencearenotdiscernablewithanopticalmicroscope.Earlyinvestigatorsinterpretedfracturemirrorsashavingdiscreteboundariesincludingax201C;mirror-mistx201D;boundaryandalsoax201C;mist-hacklex201D;boundaryinglasses.Thesewerealsotermedx201C;innermirrorx201D;orx201C;outermirrorx201D;boundaries,respectively.Itisnowknownthattherearenodiscreteboundariescorrespondingtospecificchangesinthefractographicfeatures.Surfaceroughnessincreasesgraduallyfromwellwithinthefracturemirrortobeyondtheapparentboundaries.Theboundarieswereamatterofinterpretation,theresolvingpowerofthemicroscope,andthemodeofviewing.Inveryweakspecimens,themirrormaybelargerthanthespecimenorcomponentandtheboundarieswillnotbepresent.Figs.3-5showexamplesinceramics.Inpolycrystallineceramics,thequalifierx201C;relativelyx201D;asinx201C;relativelysmoothx201D;mustbeused,sincethereisaninherentroughnessfromthemicrostructureevenintheareaimmediatelysurroundingtheorigin.Incoarse-grainedorporousceramics,itmaybeimpossibletoidentifyamirrorboundary.Inpolycrystallineceramics,itishighlyunlikelythatamirror-mistboundarycanbedetectedduetotheinherentroughnesscreatedbythecrack-microstructureinteractions,evenwithinthemirror.Thewordx201C;systematicx201D;inthedefinitionforx201C;mirror-hackleboundaryinpolycrystallineceramicsx201D;requiressomeelaboration.Mirrorboundaryhacklelinesarevelocityhacklelinescreatedaftertheradiatingcrackreachesterminalvelocity.However,premature,isolatedhacklecaninsomeinstancesbegeneratedwellwithinaceramicfracturemirror.Itshouldbedisregardedwhenjudgingthemirrorboundary.Wakehacklefromanisolatedobstacleinsidethemirror(suchasalargegrainoragglomerate)cantriggerearlyx201C;prematurex201D;hacklelines.Stepsinscratchesorgrindingflawscantriggerhacklelinesthatemanatefromtheoriginitself.Sometimesthemicrostructureofpolycrystallineceramicscreatesseverejudgmentproblemsinceramicmatrixcomposites(particulate,whisker,orplatelet)orself-reinforcedceramicswherebyelongatedandinterlockinggrainsimpartgreaterfractureresistance.Mirrorsmaybeplainlyevidentatlowmagnifications,butaccurateassessmentoftheirsizecanbedifficult.Th......