ASTM_C_1331_-_01_2012.pdf

Designation:C133101(Reapproved 2012)Standard Test Method forMeasuring Ultrasonic Velocity in Advanced Ceramics withBroadband Pulse-Echo Cross-Correlation Method1This standard is issued under the fixed designation C1331;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 describes a procedure for measurementof ultrasonic velocity in structural engineering solids such asmonolithic ceramics,toughened ceramics,and ceramic matrixcomposites.1.2 This test method is based on the broadband pulse-echocontact ultrasonic method.The procedure involves a computer-implemented,frequency-domain method for precise measure-ment of time delays between pairs of echoes returned by theback surface of a test sample or part.1.3 This test method describes a procedure for using adigital cross-correlation algorithm for velocity measurement.The cross-correlation function yields a time delay between anytwo echo waveforms(1).22.Referenced Documents2.1 ASTM Standards:3B311 Test Method for Density of Powder Metallurgy(PM)Materials Containing Less Than Two Percent PorosityC373 Test Method for Water Absorption,Bulk Density,Apparent Porosity,andApparent Specific Gravity of FiredWhiteware Products,Ceramic Tiles,and Glass TilesE494 Practice for Measuring Ultrasonic Velocity in Materi-alsE1316 Terminology for Nondestructive Examinations2.2 ASNT Document:Recommended Practice SNT-TC-1A for NondestructiveTesting Personnel Qualification and Certification42.3 Military Standard:MIL-STD-410 Nondestructive Testing Personnel Qualifica-tion and Certification52.4 Additional references are cited in the text and at end ofthis document.3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 back surfacethe surface of a test sample which isopposite to the front surface and from which back surfaceechoes are returned at normal incidence directly to the trans-ducer.3.1.2 bandwidththe frequency range of an ultrasonicprobe,defined by convention as the difference between thelower and upper frequencies at which the signal amplitude is 6dB down from the frequency at which maximum signalamplitude occurs.3.1.3 broadband transduceran ultrasonic transducer ca-pable of sending and receiving undistorted signals over a broadbandwidth,consisting of a thin damped piezocrystal in abuffered probe(search unit).3.1.4 buffered probean ultrasonic search unit as defined inTerminology E1316 but containing a delay line,or buffer rod,to which the piezocrystal is affixed within the search unithousing and which separates the piezocrystal from the testsample(Fig.1).3.1.5 buffer rodan integral part of a buffered probe,usually a quartz or fused silica cylinder that provides a timedelay between the excitation pulse from the piezocrystal andechoes returning from a sample coupled to the free end of thebuffer rod.3.1.6 cross-correlation functionthe cross-correlationfunction,implemented by a digital algorithm,yields a timedelay between any two(ultrasonic)echo waveforms.This timeis used to determine velocity(1).1This test method is under the jurisdiction of ASTM Committee C28 onAdvanced Ceramics and is the direct responsibility of Subcommittee C28.03 onPhysical Properties and Non-Destructive Evaluation.Current edition approved Aug.1,2012.Published November 2012.Originallyapproved in 1996.Last previous edition approved in 2007 as C1331 01(2007).DOI:10.1520/C1331-01R12.2The boldface numbers in parentheses refer to the list of references at the end ofthis test method.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.4Available fromAmerican Society for Nondestructive Testing(ASNT),P.O.Box28518,1711 Arlingate Ln.,Columbus,OH 43228-0518,http:/www.asnt.org.5Available from Standardization Documents Order Desk,DODSSP,Bldg.4,SectionD,700RobbinsAve.,Philadelphia,PA19111-5098,http:/www.dodssp.daps.mil.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.7 dispersionvariation of ultrasonic velocity as a func-tion of wavelength,that is,frequency dependence of velocity.3.1.8 front surfacethe surface of a test sample to whichthe buffer rod is coupled at normal incidence(designated as testsurface in Terminology E1316.3.1.9 group velocityvelocity of a broadband ultrasonicpulse consisting of many different component wavelengths.3.1.10 test samplea solid coupon or material part thatmeets the constraints needed to make the ultrasonic velocitymeasurements described herein,that is,a test sample or parthaving flat,parallel,smooth,preferably ground or polishedopposing(front and back)surfaces,and having n