BS EN 820-5-2009 Advanced technical ceramics - Thermomechanical properties of monolithic ceramics - Part 5 Determination of elastic moduli at elevated temperatures《高级工业陶瓷 单片陶瓷的热机械性.pdf

1、BS EN 820-5:2009ICS 81.060.30NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDAdvanced technicalceramics Thermomechanicalproperties ofmonolithic ceramicsPart 5: Determination of elastic moduliat elevated temperaturesThis British Standardwas published under theaut

2、hority of the StandardsPolicy and StrategyCommittee on 31 July 2009 BSI 2009ISBN 978 0 580 63846 6Amendments/corrigenda issued since publicationDate CommentsBS EN 820-5:2009National forewordThis British Standard is the UK implementation of EN 820-5:2009.The UK participation in its preparation was en

3、trusted to TechnicalCommittee RPI/13, Advanced technical ceramics.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application

4、.Compliance with a British Standard cannot confer immunityfrom legal obligations.BS EN 820-5:2009EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 820-5July 2009ICS 81.060.30 Supersedes CEN/TS 820-5:2004 English VersionAdvanced technical ceramics - Thermomechanical properties ofmonolithic ceramics -

5、 Part 5: Determination of elastic moduli atelevated temperaturesCramiques techniques avances - Propritsthermomcaniques des cramiques monolithiques - Partie5 : Dtermination des modules lastiques tempraturelevesHochleistungskeramik - ThermomechanischeEigenschaften monolithischer Keramik - Teil 5:Besti

6、mmung der elastischen Moduln bei erhhtenTemperaturenThis European Standard was approved by CEN on 12 June 2009.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alter

7、ation. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by transl

8、ationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Gr

9、eece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement

10、Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 820-5:2009: EBS EN 820-5:2009EN 820-5:2009 (E) 2 Contents Page Foreword . 31 Scope 42 Normative references . 43 Terms and definitions . 54

11、 Method A: Static bending method . 54.1 Principle . 54.2 Apparatus 54.3 Test pieces . 94.4 Procedure 94.5 Calculation of results 94.6 Accuracy and interferences . 115 Method B: Resonance method 125.1 Principle . 125.2 Apparatus 125.3 Test pieces . 155.4 Procedure 155.5 Calculation of results 165.6 A

12、ccuracy and interferences . 186 Method C: Impulse excitation method 186.1 Principle . 186.2 Apparatus 186.3 Test pieces . 216.4 Procedure 216.5 Calculation . 216.6 Accuracy and interferences . 227 Test report . 227.1 General . 227.2 Method A 237.3 Method B 237.4 Method C 24Bibliography . 25BS EN 820

13、-5:2009EN 820-5:2009 (E) 3 Foreword This document (EN 820-5:2009) has been prepared by Technical Committee CEN/TC 184 “Advanced technical ceramics”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical

14、 text or by endorsement, at the latest by January 2010, and conflicting national standards shall be withdrawn at the latest by January 2010. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held resp

15、onsible for identifying any or all such patent rights. This document supersedes CEN/TS 820-5:2004. EN 820 consists of five parts, under the general title “Advanced technical ceramics - Methods of testing monolithic ceramics - Thermomechanical properties“: Part 1: Determination of flexural strength a

16、t elevated temperatures Part 2: Determination of self-loaded deformation Part 3: Determination of resistance to thermal shock by water quenching Part 4: Determination of flexural creep deformation at elevated temperatures Part 5: Determination of elastic moduli at elevated temperatures According to

17、the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithu

18、ania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 820-5:2009EN 820-5:2009 (E) 4 1 Scope This part of EN 820 describes methods for determining the elastic moduli, specifically Youngs modulus, shear mod

19、ulus and Poissons ratio, of advanced monolithic technical ceramics at temperatures above room temperature. The standard prescribes three alternative methods for determining some or all of these three parameters: A the determination of Youngs modulus by static flexure of a thin beam in three- or four

20、-point bending. B the determination of Youngs modulus by forced longitudinal resonance, or Youngs modulus, shear modulus and Poissons ratio by forced flexural and torsional resonance, of a thin beam. C the determination of Youngs modulus from the fundamental natural frequency of a struck bar (impuls

21、e excitation method). This part of EN 820 extends the above-defined room-temperature methods described in EN 843-2 to elevated temperatures. All the test methods assume the use of homogeneous test pieces of linear elastic materials. The test assumes that the test piece has isotropic elastic properti

22、es. At high porosity levels all of the methods can become inappropriate. The maximum grain size (see EN 623-3), excluding deliberately added whiskers, should be less than 10 % of the minimum dimension of the test piece. NOTE 1 Method C in EN 843-2 based on ultrasonic time of flight measurement has n

23、ot been incorporated into this part of EN 820. Although the method is feasible to apply, it is specialised, and outside the capabilities of most laboratories. There are also severe restrictions on test piece geometries and methods of achieving pulse transmission. For these reasons this method has no

24、t been included in EN 820-5. NOTE 2 The upper temperature limit for this test depends on the properties of the test pieces, and can be limited by softening within the timescale of the test. In addition, for method A there can be limits defined by the choice of test jig construction materials. NOTE 3

25、 Methods B and C may not be appropriate for materials with significant levels of porosity (i.e. 15 %) which cause damping and an inability to detect resonances or natural frequencies, respectively. NOTE 4 This method does not provide for the effects of thermal expansion, i.e. the measurements are ba

26、sed on room temperature dimensions. Depending upon the use to which the data are put, it can be necessary to make a further correction by multiplying each dimensional factor in the relevant equations by a factor (1 + T) where is the mean linear expansion coefficient over the temperature interval T f

27、rom room temperature. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 8

28、20-1, Advanced technical ceramics Method of testing monolithic ceramics Thermo-mechanical properties Part 1: Determination of flexural strength at elevated temperatures EN 843-1:2006, Advanced technical ceramics Mechanical properties of monolithic ceramics at room temperature Part 1: Determination o

29、f flexural strength EN 60584-2, Thermocouples Part 2: Tolerances (IEC 60584-2:1982 + A1:1989) EN ISO 7500-1, Metallic materials Verification of static uniaxial testing machines Part 1: Tension/compression testing machines Verification and calibration of the force-measuring system (ISO 7500-1:2004) B

30、S EN 820-5:2009EN 820-5:2009 (E) 5 EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:2005) ISO 463, Geometrical Product Specifications (GPS) Dimensional measuring equipment Design and metrological characteristics of mechanical dial gauge

31、s ISO 3611, Micrometer callipers for external measurement ISO 6906, Vernier callipers reading to 0,02 mm 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 Youngs modulus stress required in a material to produce unit strain in uniaxial extension

32、 or compression 3.2 shear modulus shear stress required in a material to produce unit angular distortion 3.3 Poissons ratio negative value of the ratio of lateral strain to longitudinal strain in an elastic body stressed longitudinally 3.4 static elastic moduli elastic moduli determined in an isothe

33、rmal condition by stressing statically or quasistatically 3.5 dynamic elastic moduli elastic moduli determined non-quasistatically, i.e. under adiabatic conditions, such as in the resonant, ultrasonic pulse or impulse excitation methods 4 Method A: Static bending method 4.1 Principle Using three- or

34、 four-point bending of a thin beam test piece, the elastic distortion is measured, from which Youngs modulus may be calculated according to thin beam equations. 4.2 Apparatus 4.2.1 Test jig, in accordance with that described in EN 820-1 for flexural strength testing at elevated temperatures in terms

35、 of its function, i.e. the support and loading rollers shall be free to roll, and to articulate to ensure axial and even loading as described in EN 843-1. The test jig shall be made of materials which do not interact with the test piece and which remain essentially elastic at the maximum test temper

36、ature. A typical arrangement is shown in Figure 1. NOTE 1 Articulation is not essential for carefully machined flat and parallel-faced test pieces. The outer span of the test jig shall be 40 mm or greater. BS EN 820-5:2009EN 820-5:2009 (E) 6 NOTE 2 If the displacement is to be measured by method 1 (

37、see 4.2.5), a span of up to 100 mm, or a span to thickness ratio in excess of 20, is recommended to obtain large displacements and to ensure that the compliance of the machine is a small correction if displacement is recorded as a machine cross-head movement. The test jig may be either for three-poi

38、nt or four-point flexure. The latter method is required if displacement is determined by differential transducer. 4.2.2 Mechanical testing machine, capable of applying a force to the test jig at a constant displacement rate. The test machine shall be equipped for recording the load applied to the te

39、st jig at any point in time. The accuracy of the test machine shall be in accordance with EN ISO 7500-1, Grade 1 (1 % of indicated load), and shall be capable of recording to a sensitivity of better than 0,1 % of the maximum load employed. 4.2.3 Thermal enclosure and control system, surrounding the

40、test piece, capable of achieving the maximum desired temperature and maintaining it to 2 C for test temperatures up to 1 000 C, and 4 C at higher temperatures. NOTE The system can operate with an air or inert atmosphere, or with a vacuum inside the thermal enclosure. Especially with regard to use in

41、 vacuum, efforts should be made to ensure that the force applied at the test piece is correctly recorded by the load cell outside the enclosure, taking account of friction or elastic resistances in seals or bellows systems. 4.2.4 Thermocouple, conforming to EN 60584-2 for measuring the test piece te

42、mperature. The thermocouple shall be in close proximity to but shall not touch the test piece. 4.2.5 Displacement measuring device, for recording the displacement of the loaded test piece by one of two methods: Method 1 Recording the apparent displacements of the test machine as the test piece is lo

43、aded in the test jig, and again with the test piece replaced by a ceramic bar at least 15 mm thick with flat and parallel faces to within 0,05 mm. The difference between these displacements is equivalent to the displacement of the test piece in the test jig. The displacement recording device (chart

44、recorder, digital indicator, etc.) shall be calibrated by comparing machine cross-head displacement with the movement indicated on a dial gauge contacting the cross-head, or other suitable calibrated displacement measuring device. The dial gauge shall be in accordance with ISO 463, or the alternativ

45、e device otherwise certified as accurate to 0,01 mm. The parts of the load train subjected to elevated temperatures shall be made of materials which remain elastic at the maximum test temperature. Method 2 Recording the displacement of the test piece directly using a transducer extensometer contacti

46、ng at least two defined points on the surface of the test piece between the support loading rollers in three-point or four-point bending. The defined points shall preferably be: for four-point bending: the centre of the span and one or both loading rollers (see for example Figure 1, right); for thre

47、e-point bending: the centre of the span and one or both support rollers (see for example Figure 1, left). NOTE The equations given in 4.5 assume these preferred positions. Other displacement detection positions require alternative formulations. The transducer shall be capable of detecting movements

48、with an accuracy of 0,001 mm, shall have output linear to 1 % over the expected displacement range in making this test and its sensitivity shall be calibrated to an accuracy of 0,1 %. BS EN 820-5:2009EN 820-5:2009 (E) 7 The extensometer parts subjected to elevated temperatures shall remain elastic t

49、o the maximum test temperature, and their tips shall not interact with the test piece (see also EN 820-1). 4.2.6 Micrometer, in accordance with ISO 3611, capable of recording to 0,01 mm. 4.2.7 Dial gauge, conforming to ISO 463, or other suitable calibrated displacement measuring device, capable of recording to 0,01 mm. BS EN 820-5:2009EN 820-5:2009 (E) 8 1234567891011121314Key 1 Ceramic pus