ASTM_C_1211_-_13.pdf

Designation:C121113Standard Test Method forFlexural Strength of Advanced Ceramics at ElevatedTemperatures1This standard is issued under the fixed designation C1211;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.1.Scope1.1 This test method covers determination of the flexuralstrength of advanced ceramics at elevated temperatures.2Four-point-14point and three-point loadings with prescribedspans are the standard as shown in Fig.1.Rectangularspecimens of prescribed cross-section are used with specifiedfeatures in prescribed specimen-fixture combinations.Testspecimens may be 3 by 4 by 45 to 50 mm in size that are testedon 40 mm outer span four-point or three-point fixtures.Alternatively,test specimens and fixture spans half or twicethese sizes may be used.The test method permits testing ofmachined or as-fired test specimens.Several options formachining preparation are included:application matchedmachining,customary procedures,or a specified standardprocedure.This test method describes the apparatus,specimenrequirements,test procedure,calculations,and reporting re-quirements.The test 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:3C1161 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 CeramicsC1341 Test Method for Flexural Properties of ContinuousFiber-Reinforced Advanced Ceramic CompositesC1368 Test Method for Determination of Slow CrackGrowth Parameters of Advanced Ceramics by ConstantStress-Rate Strength Testing at Ambient TemperatureC1465 Test Method for Determination of Slow CrackGrowth Parameters of Advanced Ceramics by ConstantStress-Rate Flexural Testing at Elevated TemperaturesE4 Practices for Force Verification of Testing MachinesE220 Test Method for Calibration of Thermocouples ByComparison TechniquesE230 Specification and Temperature-Electromotive Force(EMF)Tables for Standardized Thermocouples3.Terminology3.1 Definitions:3.1.1 complete gage section,nthe portion of the specimenbetween the two outer bearings in four-point flexure andthree-point flexure fixtures.NOTE1In this standard,the complete four-point flexure gage sectionis twice the size of the inner gage section.Weibull statistical analyses,inthis instance,only include portions of the specimen volume or surfacewhich experience tensile stresses.3.1.2 flexural strengtha measure of the ultimate strengthof a specified beam in bending.3.1.3 four-point-1/4 point flexurea configuration of flex-ural strength testing in which a specimen is symmetricallyloaded at two locations that are situated at one-quarter of theoverall span,away from the outer two support bearings(seeFig.1).3.1.4 fully-articulating fixture,na flexure fixture designedto be used either with flat and parallel specimens or withuneven or nonparallel specimens.The fixture allows fullindependent articulation,or pivoting,of all rollers about thespecimen long axis to match the specimen surface.In addition,1This 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 1992.Last previous edition approved in 2008 as C1211 02(2008).DOI:10.1520/C1211-13.2Elevated temperatures typically denote,but are not restricted to 200 to 1600C.3For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 the upper or lower pairs are free to pivot to distribute forceevenly to the bearing cylinders on either side.NOTE2See Annex A1 for schematic illustrations of the requiredpivoting movements.NOTE3A three-point fixture has the inner pair o