ASTM_C_1684_-_13e1.pdf

Designation:C1684131Standard Test Method forFlexural Strength of Advanced Ceramics at AmbientTemperatureCylindrical Rod Strength1This standard is issued under the fixed designation C1684;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEUnits statement was added to the scope editorially in April 2014.1.Scope1.1 This test method is for the determination of flexuralstrength of rod shape specimens of advanced ceramic materialsat ambient temperature.In many instances it is preferable totest round specimens rather than rectangular bend specimens,especially if the material is fabricated in rod form.This methodpermits testing of machined,drawn,or as-fired rod shapedspecimens.It allows some latitude in the rod sizes and crosssection shape uniformity.Rod diameters between 1.5 and 8 mmand lengths from 25 to 85 mm are recommended,but othersizes are permitted.Four-point-14point as shown in Fig.1 isthe preferred testing configuration.Three-point loading ispermitted.This method describes the apparatus,specimenrequirements,test procedure,calculations,and reporting re-quirements.The method is applicable to monolithic orparticulate-or whisker-reinforced ceramics.It may also beused for glasses.It is not applicable to continuous fiber-reinforced ceramic composites.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C158 Test Methods for Strength of Glass by Flexure(De-termination of Modulus of Rupture)C1145 Terminology of Advanced CeramicsC1161 Test Method for Flexural Strength of AdvancedCeramics at Ambient TemperatureC1239 Practice for Reporting Uniaxial Strength Data andEstimating Weibull Distribution Parameters for AdvancedCeramicsC1322 Practice for Fractography and Characterization ofFracture Origins in Advanced CeramicsC1368 Test Method for Determination of Slow CrackGrowth Parameters of Advanced Ceramics by ConstantStress-Rate Strength Testing at Ambient TemperatureE4 Practices for Force Verification of Testing MachinesE337 Test Method for Measuring Humidity with a Psy-chrometer(the Measurement of Wet-and Dry-Bulb Tem-peratures)3.Terminology3.1 Definitions:3.1.1 complete gage section,nthe portion of the specimenbetween the two outer loading points in four-point flexure andthree-point flexure fixtures.C11613.1.2 flaw,na structural discontinuity in an advancedceramic body that acts as a highly localized stress raiser.3.1.2.1 DiscussionThe presence of such discontinuitiesdoes not necessarily imply that the ceramic has been preparedimproperly or is faulty.C13223.1.3 flexural strength,na measure of the ultimatestrength of a specified beam in bending.C1145,C11613.1.4 four-point-14point flexure,nconfiguration of flex-ural strength testing where a specimen is symmetrically loadedat two locations that are situated one quarter of the overall spanaway from the outer two support loading points(see Fig.1).C1145,C11613.1.5 fracture origin,nthe source from which brittlefracture commences.C1145,C13223.1.6 inert flexural strength,na measure of the strength ofspecified beam in bending as determined in an appropriate inertcondition whereby no slow crack growth occurs.3.1.6.1 DiscussionAn inert condition may be obtained by1This test method is under the jurisdiction of ASTM Committee C28 onAdvanced Ceramics and is the direct responsibility of Subcommittee C28.01 onMechanical Properties and Performance.Current edition approved Aug.1,2013.Published September 2013.Originallyapproved in 2008.Last previous edition approved in 2008 as C1684 08.DOI:10.1520/C1684-13E01.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 using vacuum,low temperatures,very fast test rates,or anyinert media.C11613.1.7 inherent flexural strength,nthe flexural strength of amaterial in the absence of any effect of surface grinding orother surface finishing process,or of extraneous damage thatmay be present.The measured inherent strength is in general afunction of the flexure test method,test conditions,andspecimen size.C11613.1.8 inner gage section,nthe portion of the specimenbetween the inner two loading points in a four-point flexurefixture.C11613.1.