Standard Test Method for Measuring Ultrasonic Velocity in Advanced Ceramics with Broadband Pulse-Echo Cross-Correlation Method

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1.1 This test method describes a procedure for measurement of ultrasonic velocity in structural engineering solids such as monolithic ceramics, toughened ceramics, and ceramic matrix composites.  
1.2 This test method is based on the broadband pulse-echo contact ultrasonic method. The procedure involves a computer-implemented, frequency-domain method for precise measurement of time delays between pairs of echoes returned by the back surface of a test sample or part.  
1.3 This test method describes a procedure for using a digital cross-correlation algorithm for velocity measurement. The cross-correlation function yields a time delay between any two echo waveforms (1).

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09-May-2001
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ASTM C1331-01 - Standard Test Method for Measuring Ultrasonic Velocity in Advanced Ceramics with Broadband Pulse-Echo Cross-Correlation Method
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:C 1331–01
Standard Test Method for
Measuring Ultrasonic Velocity in Advanced Ceramics with
1
Broadband Pulse-Echo Cross-Correlation Method
This standard is issued under the fixed designation C 1331; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2.3 Military Standard:
MIL-STD-410 Nondestructive Testing Personnel Qualifica-
1.1 Thistestmethoddescribesaprocedureformeasurement
5
tion and Certification
of ultrasonic velocity in structural engineering solids such as
2.4 Additional references are cited in the text and at end of
monolithic ceramics, toughened ceramics, and ceramic matrix
this document.
composites.
1.2 This test method is based on the broadband pulse-echo
contactultrasonicmethod.Theprocedureinvolvesacomputer-
3. Terminology
implemented, frequency-domain method for precise measure-
3.1 Definitions of Terms Specific to This Standard:
ment of time delays between pairs of echoes returned by the
3.1.1 back surface—the surface of a test sample which is
back surface of a test sample or part.
opposite to the front surface and from which back surface
1.3 This test method describes a procedure for using a
echoes are returned at normal incidence directly to the trans-
digital cross-correlation algorithm for velocity measurement.
ducer.
Thecross-correlationfunctionyieldsatimedelaybetweenany
2
3.1.2 bandwidth—the frequency range of an ultrasonic
two echo waveforms (1).
probe, defined by convention as the difference between the
2. Referenced Documents lowerandupperfrequenciesatwhichthesignalamplitudeis6
3
dB down from the frequency at which maximum signal
2.1 ASTM Standards:
amplitude occurs.
B311 Test Method for Density Determination for Powder
3.1.3 broadband transducer—an ultrasonic transducer ca-
Metallurgy (P/M) Materials Containing Less Than Two
pableofsendingandreceivingundistortedsignalsoverabroad
Percent Porosity
bandwidth, consisting of a thin damped piezocrystal in a
C373 Test Method for Water Absorption, Bulk Density,
buffered probe (search unit).
Apparent Porosity, andApparent Specific Gravity of Fired
3.1.4 buffered probe—anultrasonicsearchunitasdefinedin
Whiteware Products
Terminology E1316 but containing a delay line, or buffer rod,
E494 Practice for Measuring Ultrasonic Velocity in Mate-
to which the piezocrystal is affixed within the search unit
rials
housing and which separates the piezocrystal from the test
E1316 Terminology for Nondestructive Examinations
sample (Fig. 1).
2.2 ASNT Document:
3.1.5 buffer rod—an integral part of a buffered probe,
Recommended Practice SNT-TC-1A for Nondestructive
4
usually a quartz or fused silica cylinder that provides a time
Testing Personnel Qualification and Certification
delay between the excitation pulse from the piezocrystal and
echoes returning from a sample coupled to the free end of the
1
This test method is under the jurisdiction of ASTM Committee C28 on buffer rod.
Advanced Ceramics and is the direct responsibility of Subcommittee C28.03 on
3.1.6 cross-correlation function—the cross-correlation
Physical Properties and Performance.
function, implemented by a digital algorithm, yields a time
Current edition approved May 10, 2001. Published July 2001. Originally
delaybetweenanytwo(ultrasonic)echowaveforms.Thistime
published as C 1331–96. Last previous edition C 1331–96.
2
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
is used to determine velocity (1).
this test method.
3.1.7 dispersion—variation of ultrasonic velocity as a func-
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
tion of wavelength, that is, frequency dependence of velocity.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standardsvolume information,referto thestandard’sDocumentSummary page on
the ASTM website.
4 5
Available from the American Society for Nondestructive Testing, 1711 Arlin- AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
gate Ln., Columbus, OH 43228. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

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C 1331–01
4. Significance and Use
4.1 Thevelocitymeasurementsdescribedinthistestmethod
may be used to characterize material variations that affect
mechanical or physical properties.This procedure is useful for
measuring variations in microstructural features such as grain
structure, pore fractions, and density variations in monolithic
ceramics.
4.2 Velocity measurements described herein can
...

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