1、Designation: E289 04 (Reapproved 2016)E289 17Standard Test Method forLinear Thermal Expansion of Rigid Solids withInterferometry1This standard is issued under the fixed designation E289; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, 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 linear thermal expansion of rigid solids using either a M
3、ichelson or Fizeauinterferometer.1.2 For this purpose, a rigid solid is defined as a material which, at test temperature and under the stresses imposed byinstrumentation, has a negligible creep, insofar as significantly affecting the precision of thermal length change measurements.1.3 It is recogniz
4、ed that many rigid solids require detailed preconditioning and specific thermal test schedules for correctevaluation of linear thermal expansion behavior for certain material applications. Since a general method of test cannot cover allspecific requirements, details of this nature should be discusse
5、d in the particular material specifications.1.4 This test method is applicable to the approximate temperature range 150150C to 700C. The temperature range may beextended depending on the instrumentation and calibration materials used.1.5 The precision of measurement of this absolute method (better t
6、han 640 nm/(mK) is significantly higher than that ofcomparative methods such as push rod dilatometry (for example, Test Methods D696 and E228) and thermomechanical analysis(for example, Test Method E831) techniques. It is applicable to materials having low and either positive or negative coefficient
7、sof expansion (below 5 m/(mK) and where only very limited lengths or thickness of other higher expansion coefficient materialsare available.1.6 Computer or electronic based instrumentation, techniques and data analysis systems equivalent to this test method can beused. Users of the test method are e
8、xpressly advised that all such instruments or techniques may not be equivalent. It is theresponsibility of the user to determine the necessary equivalency prior to use.1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.7 Th
9、is standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.8 This international
10、standard was developed in accordance with internationally recognized principles on standardizationestablished 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.
11、Referenced Documents2.1 ASTM Standards:2D696 Test Method for Coefficient of Linear Thermal Expansion of Plastics Between 30C and 30C with a Vitreous SilicaDilatometerE220 Test Method for Calibration of Thermocouples By Comparison TechniquesE228 Test Method for Linear Thermal Expansion of Solid Mater
12、ials With a Push-Rod DilatometerE473 Terminology Relating to Thermal Analysis and RheologyE831 Test Method for Linear Thermal Expansion of Solid Materials by Thermomechanical Analysis1 This test method is under jurisdiction of ASTM Committee E37 on Thermal Measurements and is the direct responsibili
13、ty of Subcommittee E37.05 on ThermophysicalProperties.Current edition approved Sept. 1, 2016April 1, 2017. Published September 2016April 2017. Originally approved in 1965. Last previous edition approved in 20102016 asE289 04 (2010).(2016). DOI: 10.1520/E0289-04R16.10.1520/E0289-17.2 For referencedAS
14、TM standards, visit theASTM 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
15、of an ASTM standard an indication 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 p
16、ublished by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1E1142 Terminology Relating to Thermophysical Properties3. Terminology3.1 Definitions:3.1.1 The following terms are applicable t
17、o this document and are listed in Terminology E473 and E1142: coeffcient of linearthermal expansion,thermodilatometry, and thermomechanical analysis.3.2 Definitions of Terms Specific to This Standard:3.2.1 mean coeffcient of linear thermal expansion, mthe average change in length relative to the len
18、gth of the specimenaccompanying a change in temperature between temperatures T1 and T2, expressed as follows:m 5 1L0L22L1T22T15 1LoLT (1)where m is obtained by dividing the linear thermal expansion (L/L0) by the change of temperature (T). It is normallyexpressed as m/mK. Dimensions (L) are normally
19、expressed in mm and wavelength () in nm.3.2.2 spalling, nthe development of fragments, flakes, or chips usually caused by stress resulting from mechanical treatment.3.2.3 thermal expansivity, Tat temperature T, is calculated as follows from slope of length v temperature curve:T 5 1LiT2T1limit L22L1T
20、22T1 51LidLdT with T1,Ti,T2 (2)and expressed as m/mK.3.2.3.1 DiscussionThermal expansivity is sometimes referred to as instantaneous coefficient of linear expansion.3.3 Symbols:m = mean coefficient of linear thermal expansion, see 3.2.2, /K1T = expansivity at temperature T, see 3.2.1, / K1L0 = origi
21、nal length of specimen at temperature T0, mmL1 = length at temperature T1, mmL2 = length at temperature T2, mmL = change in length of specimen between temperatures T1 and T2, nmLs = change in length of reference specimen between T1 and T2, mmN = number of fringes including fractional parts that are
22、measured on changing temperature from T1 to T2n = index of refraction of gas at temperature T and pressure, Pnr = index of refraction of gas at reference condition of temperature 288K and pressure of 100 kPan1, n2 = index of refractive of gas at temperature T1 and T2, and pressure, PP = average pres
23、sure of gas during test, torrT0 = temperature at which initial length is L0, KT1, T2 = two temperatures at which measurements are made, KT = temperature difference between T2 and T1, Kv = wavelength of light used to produce fringes, nmm = mean coefficient of linear thermal expansion, see 3.2.1, K1T
24、= expansivity at temperature T, see 3.2.3, K1L0 = original length of specimen at temperature T0, mmL1 = length at temperature T1, mmL2 = length at temperature T2, mmL = change in length of specimen between temperatures T1 and T2, nmLs = change in length of reference specimen between T1 and T2, mmN =
25、 number of fringes including fractional parts that are measured on changing temperature from T1 to T2n = index of refraction of gas at temperature T and pressure, Pnr = index of refraction of gas at reference condition of temperature 288 K and pressure of 100 kPan1, n2 = index of refractive of gas a
26、t temperature T1 and T2, and pressure, PP = average pressure of gas during test, Pa (torr)Notetorr = 133.3 Pa.T0 = temperature at which initial length is L0, KT1, T2 = two temperatures at which measurements are made, KT = temperature difference between T2 and T1, Kv = wavelength of light used to pro
27、duce fringes, nm4. Summary of Test Method4.1 A specimen of known geometry can be given polished reflective ends or placed between two flat reflecting surfaces(mirrors). Typical configurations, as shown in Fig. 1, are a cylindrical tube or a rod with hemispherical or flat parallel ends orE289 172mach
28、ined to provide a 3-point support. The mirrors consist of flat-uniform thickness pieces of silica or sapphire with the surfacespartially coated with gold or other high reflectance metal. Light, either parallel laser beam (Michelson, see Fig. 2 and Fig. 3) orfrom a point monochromatic source (Fizeau,
29、 see Fig. 4) illuminates each surface simultaneously to produce a fringe pattern. Asthe specimen is heated or cooled, expansion or contraction of the specimen causes a change in the fringe pattern due to the opticalpathlength difference between the reflecting surfaces. This change is detected and co
30、nverted into length change from which theexpansion and expansion coefficient can be determined (1-5).35. Significance and Use5.1 Coefficients of linear expansion are required for design purposes and are used particularly to determine thermal stresses thatcan occur when a solid artifact composed of d
31、ifferent materials may fail when it is subjected to a temperature excursion(s).5.2 Many new composites are being produced that have very low thermal expansion coefficients for use in applications wherevery precise and critical alignment of components is necessary. Push rod dilatometry such as Test M
32、ethods D696, and E228, andTMAthermomechanical analysis methods such asTest MethodsMethod E831 are not sufficiently precise for reliable measurementseither on such material and systems, or on very short specimens of materials having higher coefficients.5.3 The precision of the absolute method allows
33、for its use to:5.3.1 Measure very small changes in length;5.3.2 Develop reference materials and transfer standards for calibration of other less precise techniques;5.3.3 Measure and compare precisely the differences in coefficient of “matched” materials.3 The boldface numbers in parentheses refer to
34、 a list of references at the end of this standard.FIG. 1 Typical Specimen Configurations (a) Michelson Type, (bd) Fizeau TypeFIG. 2 (a) Principle of the Single Pass Michelson Interferometer, (b) Typical Single Pass SystemE289 1735.4 The precise measurement of thermal expansion involves two parameter
35、s; change of length and change of temperature. Sinceprecise measurements of the first parameter can be made by this test method, it is essential that great attention is also paid to thesecond, in order to ensure that calculated expansion coefficients are based on the required temperature difference.
36、 Thus in orderto ensure the necessary uniformity in temperature of the specimen, it is essential that the uniform temperature zone of thesurrounding furnace or environmental chamber shall be made significantly longer than the combined length of specimen andmirrors.5.5 This test method contains essen
37、tial details of the design principles, specimen configurations, and procedures to provideprecise values of thermal expansion. It is not practical in a method of this type to try to establish specific details of design,construction, and procedures to cover all contingencies that might present difficu
38、lties to a person not having the technicalknowledge relating to the thermal measurements and general testing practice. Standardization of the method is not intended torestrict in any way further development of improved methodology.5.6 The test method can be used for research, development, specificat
39、ion acceptance and quality control and assurance.FIG. 3 Typical Double Pass Michelson Interferometer SystemFIG. 4 Principle of the Fizeau InterferometerE289 1746. Interferences6.1 Measurements should normally be undertaken with the specimen in vacuum or in helium at a low gas pressure in order tooff
40、-set optical drifts resulting from instabilities of the refractive index of air or other gases at normal pressures. However, due tothe reduced heat transfer coefficient from the surrounding environment, measurement in vacuum or low pressure can make actualspecimen temperature measurement more diffic
41、ult. Additional care and longer equilibrium time to ensure that the specimen is ata uniform temperature are necessary.6.2 If vitreous silica flats are used, continuous heating to high temperatures may cause them to distort and become cloudyresulting in poor fringe definition.7. Apparatus7.1 Interfer
42、ometer, Michelson Type:7.1.1 The principle of the single pass absolute system is shown in Fig. 2a. A parallel light beam usually generated from a laserthrough a beam expander is split by a beam splitter B. The resulting beams are reflected by mirrors M1 and M2 and recombinedon B. If M2 is inclined s
43、lightly over the light-beam its mirror image M2 forms a small angle with M1 producing fringes of equalthickness located on the virtual face M2.7.1.2 One example of a single contact type is shown in Fig. 2b. A prism or a polished very flat faced cylindrical specimen isplaced on one mirror with one fa
44、ce also offered to the incident light. An interference pattern is generated and this is divided intotwo fields corresponding to each end of the specimen. The lens, L, projects the image of the fringes onto a plane where twodetectors are placed one on the specimen and the other on the baseplate field
45、s. As the specimen is heated or cooled, both thespecimen and support change of lengths cause the surface S and M2 to move relative to M1 at different rates. The difference inthe fringe count provides a measure of the net absolute expansion.7.1.3 The principle of the double pass system is essentially
46、 similar to the single pass with three important distinctions. Thespecimen can be a relatively simple cylinder with hemispherical or flat ends and requiring less precise machining, the interferingbeams are reflected twice from each face to the specimen thus giving twice the sensitivity of the single
47、 pass, and no reference armis required. One example of the double pass form is shown in Fig. 3.7.1.4 It is common practice to use polarized laser light and quarter wave plates to generate circularly polarized light. In this waydetectors combined with appropriate analyzers generate signals either wit
48、h information on fringe number, fraction and motionsense for each beam or linear array data of light intensity, which indicate the profile of the instantaneous whole fringe pattern. Thearray data provides complete information (position of fringe and distance between fringes) to determine the absolut
49、e length changeof the specimen depending upon the system. These signals are normally processed electronically.7.2 Fizeau Type:7.2.1 This type is available in both absolute and comparative versions.7.2.2 The principle of the absolute method is illustrated in Fig. 4. The specimen is retained between two parallel plates andilluminated by the point source. Expansion or contraction of the specimen causes spatial variation between the plates and radialmotion of the circular fringe pattern.7.2.3 The difference in the fringe counts
