ASTM_C_1834_-_16.pdf

Designation:C183416Standard Test Method forDetermination of Slow Crack Growth Parameters ofAdvanced Ceramics by Constant Stress Flexural Testing(Stress Rupture)at Elevated Temperatures1This standard is issued under the fixed designation C1834;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 the determination of the slowcrack growth(SCG)parameters of advanced ceramics in agiven test environment at elevated temperatures in which thetime-to-failure of four-point-14point flexural test specimens(see Fig.1)is determined as a function of different levels ofconstant applied stress.This SCG constant stress test procedureis also called a slow crack growth(SCG)stress rupture test.The test method addresses the test equipment,test specimenfabrication,test stress levels and experimental procedures,datacollection and analysis,and reporting requirements.1.2 In this test method the decrease in time-to-failure withincreasing levels of applied stress in specified test conditionsand temperatures is measured and used to analyze the slowcrack growth parameters of the ceramic.The preferred analysismethod is based on a power law relationship between crackvelocity and applied stress intensity;alternative analysis ap-proaches are also discussed for situations where the power lawrelationship is not applicable.NOTE1This test method is historically referred to in earlier technicalliterature as static fatigue testing(Refs 1-3)2in which the term fatigue isused interchangeably with the term slow crack growth.To avoid possibleconfusion with the fatigue phenomenon of a material that occurs exclu-sively under cyclic stress loading,as defined in E1823,this test methoduses the term constant stress testing rather than static fatigue testing.1.3 This test method uses a 4-point-14point flexural testmode and applies primarily to monolithic advanced ceramicsthat are macroscopically homogeneous and isotropic.This testmethod may also be applied to certain whisker-or particle-reinforced ceramics as well as certain discontinuous fiber-reinforced composite ceramics that exhibit macroscopicallyhomogeneous behavior.Generally,continuous fiber ceramiccompositesdonotexhibitmacroscopicallyisotropic,homogeneous,elastic continuous behavior,and the applicationof this test method to these materials is not recommended.1.4 This test method is intended for use at elevated tem-peratures with various test environments such as air,vacuum,inert gas,and steam.This test method is similar to Test MethodC1576 with the addition of provisions for testing at elevatedtemperatures to establish the effects of those temperatures onslow crack growth.The elevated temperature testing provisionsare derived from Test Methods C1211 and C1465.1.5 Creep deformation at elevated temperatures can occur insome ceramics as a competitive mechanism with slow crackgrowth.Those creep effects may interact and interfere with theslow crack growth effects(see 5.5).This test method isintended to be used primarily for ceramic test specimens withnegligible creep.This test method imposes specific upper-bound limits on measured maximum creep strain at fracture orrun-out(no more than 0.1%,in accordance with 5.5).1.6 The values stated in SI units are to be regarded as thestandard and in accordance with IEEE/ASTM SI 10.1.7 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:3C1145 Terminology of Advanced CeramicsC1161 Test Method for Flexural Strength of AdvancedCeramics at Ambient TemperatureC1211 Test Method for Flexural Strength of AdvancedCeramics at Elevated TemperaturesC1239 Practice for Reporting Uniaxial Strength Data andEstimating Weibull Distribution Parameters for AdvancedCeramics1This 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 Feb.1,2016.Published April 2016.DOI:10.1520/C1834-16.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 C1291 Test Method for Elevated Temperature Tensile CreepStrain,Creep Strain Rate,and Creep Time-to