1、Designation: C1332 01 (Reapproved 2013)C1332 18Standard Test Method Practice forMeasurement of Ultrasonic Attenuation Coefficients ofAdvanced Ceramics by Pulse-Echo Contact Technique1This standard is issued under the fixed designation C1332; the number immediately following the designation indicates
2、 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. Scope Scope*1.1 This test method practice describes a pr
3、ocedure for measurement of ultrasonic attenuation coefficients for advancedstructural ceramic materials. The procedure is based on a broadband buffered piezoelectric probe used in the pulse-echo contactmode and emitting either longitudinal or shear waves. The primary objective of this test method pr
4、actice is materialscharacterization.1.2 The procedure requires coupling an ultrasonic probe to the surface of a plate-like sample and the recovery of successivefront surface and back surface echoes. echoes (refer to Fig. 3). Power spectra of the echoes are used to calculate the attenuationspectrum (
5、attenuation coefficient as a function of ultrasonic frequency) for the sample material. The transducer bandwidth andspectral response are selected to cover a range of frequencies and corresponding wavelengths that interact with microstructuralfeatures of interest in solid test samples.1.3 The purpos
6、e of this test method practice is to establish fundamental procedures for measurement of ultrasonic attenuationcoefficients. These measurements should distinguish and quantify microstructural differences among solid samples and thereforehelp establish a reference database for comparing materials and
7、 calibrating ultrasonic attenuation measurement equipment.1.4 This test method practice applies to monolithic ceramics and also polycrystalline metals. This test method practice may beapplied to whisker reinforced ceramics, particulate toughened ceramics, and ceramic composites provided that similar
8、 constraintson sample size, shape, and finish are met as described herein for monolithic ceramics.1.5 This test method practice sets forth the constraints on sample size, shape, and finish that will assure valid attenuationcoefficient measurements. This test method practice also describes the instru
9、mentation, methods, and data processing proceduresfor accomplishing the measurements.1.6 This test method practice is not recommended for highly attenuating materials such as very thick, very porous,rough-surfaced monolithics or composites. This test method practice is not recommended for highly non
10、uniform, heterogeneous,cracked, defective, or otherwise flaw-ridden samples that are unrepresentative of the nature or inherent characteristics of thematerial under examination.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the respon
11、sibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.8 This international standard was developed in accordance with internationally recognized principles on stand
12、ardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C1331 Practice for Measuring UltrasonicVelocity
13、inAdvanced Ceramics with Broadband Pulse-Echo Cross-Correlation MethodE543 Specification for Agencies Performing Nondestructive Testing1 This test method practice is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.06 onUltra
14、sonic Method.Current edition approved Feb. 1, 2013Feb. 1, 2018. Published April 2013February 2018. Originally approved in 1996. Last previous edition approved in 20072013 asC1332C1332 01 (2013). 01 (2007). DOI: 10.1520/C1332-01R13. DOI: 10.1520/C1332-18.2 For referencedASTM standards, visit theASTM
15、website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indic
16、ation of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be co
17、nsidered the official document.*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 States1E664E664/E664M Practice for the Measurement of the Apparent Attenuation of Longitudinal Ul
18、trasonic Waves by ImmersionMethodE1316 Terminology for Nondestructive ExaminationsE1495E1495/E1495M Guide for Acousto-Ultrasonic Assessment of Composites, Laminates, and Bonded Joints2.2 ASNT Document:Documents:3Recommended Practice SNT-TC-1A for Nondestructive Testing Personnel Qualification and Ce
19、rtificationANSI/ASNT CP-189 Standard for Qualification and Certification of Nondestructive Testing Personnel2.3 MilitaryISO Standard:MIL-STD-410 ISO 9712 Nondestructive Testing Personnel Qualification Non-destructive Testing Qualification and Certifi-cation of NDT Personnel42.4 Aerospace Industries
20、Association Document:NAS 410 Certification and Qualification of Nondestructive Testing Personnel52.5 Additional references are cited in the text and at end of this test method.practice.3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 acoustic impedance (Z)a property (1)6 define
21、d by a materials density, p, and the velocity of sound within it, v, whereZ = v.3.1.2 attenuation coeffcient ()decrease in ultrasound intensity with distance expressed in nepers (Np) per unit length, herein, = ln(I0/I)/d, where is attenuation coefficient, d is path length or distance, I0 is original
22、 intensity and I is attenuated intensity(2).3.1.3 attenuation spectrumthe attenuation coefficient, , expressed as a function of ultrasonic frequency, f, or plotted as versus f, over a range of ultrasonic frequencies within the bandwidth of the transducer and associated pulser-receiverinstrumentation
23、.3.1.4 back surfacethe surface of a test sample which is opposite to the front surface and from which back surface echoes arereturned at normal incidence directly to the transducer.3.1.5 bandwidththe frequency range of an ultrasonic probe, defined by convention as the difference between the lower an
24、dupper frequencies at which the signal amplitude is 6 dB down from the frequency at which maximum signal amplitude occurs. Thefrequency at which the maximum occurs is termed the center frequency of the probe or transducer.3.1.6 broadband transduceran ultrasonic transducer capable of sending and rece
25、iving undistorted signals over a broadbandwidth, consisting of thin damped piezoelectric crystal in a buffered probe (search unit).3.1.7 buffered probean ultrasonic search unit as defined in Terminology E1316 but containing a delay line or buffer rod towhich the piezoelement, that is, transducer con
26、sisting of a piezoelectric crystal, is affixed. The buffer rod separates thepiezoelement from the test sample (see Fig. 1).3.1.8 buffer rodan integral part of a buffered probe or search unit, usually a quartz or fused silica cylinder that provides a timedelay between the excitation pulse from the pi
27、ezoelement and echoes returning from a sample coupled to the free end of the bufferrod.3 Available from American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.4 Available from Standardization Documents Order Desk, DODSSP, B
28、ldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/www.dodssp.daps.mil.International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,Switzerland, http:/www.iso.org.5 Available from Aerospace Industrie
29、s Association of America, Inc., 1250 Eye St. NW, Washington, DC, 20005.6 The boldface numbers in parentheses refer to a list of references at the end of this standard.FIG. 1 Cross Section of Buffered Broadband Ultrasonic ProbeC1332 1823.1.9 free surfacethe back surface of a solid test sample interfa
30、ced with a very low density medium, usually air or other gas,to assure that the back surface reflection coefficient equals 1 to a high degree of precision.3.1.10 frequency (f)number of oscillations per second of ultrasonic waves, measured in megahertz, MHz, herein.3.1.11 front surfacethe surface of
31、a test sample to which the buffer rod is coupled at normal incidence (designated as testsurface in Terminology E1316).3.1.12 inherent attenuationultrasound energy loss in a solid as a result of scattering, diffusion, and absorption. This standardassumes that the dominant inherent losses are due to R
32、ayleigh and stochastic scattering (2) by the material microstructure, forexample, by grains, grain boundaries, and micropores. Measured ultrasound energy loss which, if not corrected, may include lossesdue to diffraction, individual macroflaws, surface roughness, couplant variations, and transducer
33、defects.3.1.13 reflection coeffcient (R)measure of relative intensity of sound waves reflected back into a material at an interface,defined in terms of the acoustic impedance of the material in which the sound wave originates (Z0) and the acoustic impedanceof the material interfaced with it (Zi), wh
34、ere R = (Zi Z0)/(Zi + Z0)2.3.1.14 test samplea solid coupon or material part that meets the constraints needed to make the attenuation coefficientmeasurements described herein, that is, a test sample or part having flat, parallel, smooth, preferably ground/polished opposing(front and back) surfaces
35、and having no discrete flaws or anomalies that are unrepresentative of the inherent properties of thematerial.FIG. 2 Block Diagram of Computer System for Ultrasonic Signal Acquisition and Processing for Pulse-Echo Attenuation MeasurementFIG. 3 Schematic of Signal Acquisition and Data-Processing Stag
36、es for Determining Frequency Dependence of Attenuation Coefficientby Using Broadband Ultrasonic Pulse-Echo MethodC1332 1833.1.15 transmission coeffcient (T)measure of relative intensity of sound waves transmitted through an interface, defined interms of the acoustic impedance of the material in whic
37、h the sound wave originates (Z0) and the acoustic impedance of the materialinterfaced with it (Zi), where T = (4ZiZ0)/(Zi + Z0)2 so that R + T = 1.3.1.16 wavelength ()distance that sound (of a particular frequency) travels during one period (during one oscillation), =v/f, where v is the velocity of
38、sound in the material and where velocity is measured in cm/s, and wavelength in cm, herein.3.2 Other terms used in this test method practice are defined in Terminology E1316.4. Summary of Test Method4.1 This test method describes a procedure for determining a materials inherent attenuation coefficie
39、nt and attenuation spectrumby means of a buffered broadband probe operating in the pulse-echo contact mode on a solid sample that has smooth, flat, parallelsurfaces.4.2 The procedure described in this test method involves digital acquisition and computer processing of ultrasonic echowaveforms return
40、ed by the test sample. Test sample constraints, probing methods, data validity criteria, and measurementcorrections are prescribed herein.4. Summary of Practice4.1 This practice describes a procedure for determining a materials inherent attenuation coefficient and attenuation spectrumby means of a b
41、uffered broadband probe operating in the pulse-echo contact mode on a solid sample that has smooth, flat, parallelsurfaces.4.2 The procedure described in this practice involves digital acquisition and computer processing of ultrasonic echo waveformsreturned by the test sample. Test sample constraint
42、s, probing methods, data validity criteria, and measurement corrections areprescribed herein.5. Significance and Use5.1 This test method practice is useful for characterizing material microstructure or measuring variations in microstructure thatoccur because of material processing conditions and the
43、rmal, mechanical, or chemical exposure (3). When applied to monolithicor composite ceramics, the procedure should reveal microstructural gradients due to density, porosity, and grain variations. Thistest method practice may also be applied to polycrystalline metals to assess variations in grain size
44、, porosity, and multiphaseconstituents.5.2 This test method practice is useful for measuring and comparing microstructural variations among different samples of thesame material or for sensing and measuring subtle microstructural variations within a given sample.5.3 This test method practice is usef
45、ul for mapping variations in the attenuation coefficient and the attenuation spectrum as theypertain to variations in the microstructure and associated properties of monolithic ceramics, ceramic composites and metals.5.4 This test method practice is useful for establishing a reference database for c
46、omparing materials and for calibratingultrasonic attenuation measurement equipment.5.5 This test method practice is not recommended for highly attenuating monolithics or composites that are thick, highly porous,or that have rough or highly textured surfaces. For these materials Practice E664E664/E66
47、4M may be appropriate. GuideE1495E1495/E1495M is recommended for assessing attenuation differences among composite plates and laminates that mayexhibit, for example, pervasive matrix porosity or matrix crazing in addition to having complex fiber architectures orthermomechanical degradation (3). The
48、proposed ASTM Standard Test Method Practice for Measuring Ultrasonic Velocity inAdvanced Ceramics (C1331) is recommended for characterizing monolithic ceramics with significant porosity or porosityvariations (4).6. Personnel Qualifications6.1 It is recommended that nondestructive evaluation/examinat
49、ion personnel applying this test methodIf specified in thecontractual agreement, personnel performing examinations to this practice shall be qualified in accordance with a nationally orinternationally recognized NDT personnel qualification practice or standard such as ASNT SNT-TC-1A, MIL STD 410,ANSI/ASNT CP-189, SNT-TC-1A, NAS 410, ISO 9712, or a similar document. The qualification document and certified by theemployer or certifying agency, as applicable. The practice or standard used and its applicable revision(s) shouldrevision sha
