ASTM_C_1576_-_05_2017.pdf

Designation:C157605(Reapproved 2017)Standard Test Method forDetermination of Slow Crack Growth Parameters ofAdvanced Ceramics by Constant Stress Flexural Testing(Stress Rupture)at Ambient Temperature1This standard is issued under the fixed designation C1576;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 standard test method covers the determination ofslow crack growth(SCG)parameters of advanced ceramics byusing constant stress flexural testing in which time to failure offlexure test specimens is determined in four-point flexure as afunction of constant applied stress in a given environment atambient temperature.In addition,test specimen fabricationmethods,test stress levels,data collection and analysis,andreporting procedures are addressed.The decrease in time tofailure with increasing applied stress in a specified environ-ment is the basis of this test method that enables the evaluationof slow crack growth parameters of a material.The preferredanalysis in the present method is based on a power lawrelationship between crack velocity and applied stress inten-sity;alternative analysis approaches are also discussed forsituations where the power law relationship is not applicable.NOTE1The test method in this standard is frequently referred to as“static fatigue”or stress-rupture testing(1-3)2in which the term“fatigue”is used interchangeably with the term“slow crack growth.”To avoidpossible confusion with the“fatigue”phenomenon of a material thatoccurs exclusively under cyclic loading,as defined in Terminology E1823,this test method uses the term“constant stress testing”rather than“staticfatigue”testing.1.2 This test method applies primarily to monolithic ad-vanced ceramics that are macroscopically homogeneous andisotropic.This test method may also be applied to certainwhisker-or particle-reinforced ceramics as well as certaindiscontinuous fiber-reinforced composite ceramics that exhibitmacroscopically homogeneous behavior.Generally,continuousfiber ceramic composites do not exhibit macroscopicallyisotropic,homogeneous,continuous behavior,and the applica-tion of this test method to these materials is not recommended.1.3 This test method is intended for use with various testenvironments such as air,other gaseous environments,andliquids.1.4 The values stated in SI units are to be regarded as thestandard and in accordance with IEEE/ASTM SI 10 Standard.1.5 This test method may involve hazardous materials,operations,and equipment.This standard does not purport toaddress all of the safety concerns associated with its use.It isthe responsibility of the user of this standard to establishappropriate safety and health practices and determine theapplicability 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 TemperatureC1322 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 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 MachinesE6 Terminology Relating to Methods of Mechanical TestingE112 Test Methods for Determining Average Grain SizeE337 Test Method for Measuring Humidity with a Psy-chrometer(the Measurement of Wet-and Dry-Bulb Tem-peratures)E399 Test Method for Linear-Elastic Plane-Strain FractureToughness KIcof Metallic MaterialsE1823 Terminology Relating to Fatigue and Fracture Testing3.Terminology3.1 Definitions:1This practice is under the jurisdiction of ASTM Committee C28 on AdvancedCeramics and is the direct responsibility of Subcommittee C28.01 on MechanicalProperties and Performance.Current edition approved Feb.1,2017.Published February 2017.Originallyapproved in 2005.Last previous edition approved in 2010 as C1576 05(2010).DOI:10.1520/C1576-05R17.2The boldface numbers in parentheses refer to a 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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and R