DIN EN 843-1-2008 Advanced technical ceramics - Mechanical properties of monolithic ceramics at room temperature - Part 1 Determination of flexural strength English version of DIN .pdf

1、August 2008DEUTSCHE NORM English price group 11No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 81.060.30!$Q3“1461690ww

2、w.din.deDDIN EN 843-1Advanced technical ceramics Mechanical properties of monolithic ceramics at room temperature Part 1: Determination of flexural strengthEnglish version of DIN EN 843-1:2008-08Hochleistungskeramik Mechanische Eigenschaften monolithischer Keramik bei Raumtemperatur Teil 1: Bestimmu

3、ng der BiegefestigkeitEnglische Fassung DIN EN 843-1:2008-08SupersedesDIN EN 843-1:2007-03www.beuth.deDocument comprises 22 pagesDIN EN 843-1:2008-08 2 National foreword This standard has been prepared by Technical Committee CEN/TC 184 “Advanced technical ceramics” (Secretariat: BSI, United Kingdom)

4、. The responsible German body involved in its preparation was the Normenausschuss Materialprfung (Materials Testing Standards Committee), Technical Committee NA 062-02-91 AA Hochleistungskeramik Monolithische Werkstoffe. The DIN Standard corresponding to the International Standard referred to in cla

5、use 2 of the EN is as follows: ISO 3611 DIN 863-1 Amendments This standard differs from DIN EN 843-1:1995-04 as follows: a) The resolution of the micrometer has been changed from 0,01 mm to 0,002 mm (see 5.3). b) The drying temperature for test pieces has been changed from (110 5) C to (120 10) C. c

6、) The standard has been editorially revised. Compared with DIN EN 843-1:2007-03, the following corrections have been made: a) In Table 1 (see 6.2), the value of size A, column “Thickness” has been changed from 2,5 to 2,0. b) In Table 1 (see 6.2), the value of size B, column “Length” has been changed

7、 from 45 to 45. c) In 6.3.3, 5thparagraph, it shall read: “of at least 0,06 mm of material”. d) In 6.3.6, in note 2, reference 1 has been replaced by reference 4. Previous editions DIN EN 843-1: 1995-04, 2007-03 National Annex NA (informative) Bibliography DIN 863-1, Verification of geometrical para

8、meters Micrometers Part 1: Standard design micrometer callipers for external measurement; concepts, requirements, testing EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 843-1December 2006ICS 81.060.30 Supersedes EN 843-1:1995 English VersionAdvanced technical ceramics - Mechanical properties ofmo

9、nolithic ceramics at room temperature - Part 1: Determinationof flexural strengthCramiques techniques avances - Proprits mcaniquesdes cramiques monolithiques temprature ambiante -Partie 1: Dtermination de la rsistance en flexionHochleistungskeramik - Mechanische Eigenschaftenmonolithischer Keramik b

10、ei Raumtemperatur - Teil 1:Bestimmung der BiegefestigkeitThis European Standard was approved by CEN on 11 November 2006.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

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

12、 translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece,

13、 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 Centr

14、e: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 843-1:2006: EEN 843-1:2006 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Terms and definitions .5 4 Significance and use

15、 .5 5 Apparatus .6 5.1 Test jig 6 5.2 Test machine8 5.3 Micrometer or alternative calibrated device .8 5.4 Travelling microscope.8 5.5 Humidity measuring device 9 6 Test pieces .9 6.1 General9 6.2 Dimensions and tolerances 9 6.3 Surface finish .10 6.4 Number of test pieces .13 6.5 Precautions 13 7 P

16、rocedure .13 8 Calculations14 9 Test report 15 Annex A (informative) Typical fracture patterns in ceramic test pieces .17 Bibliography 20 DIN EN 843-1:2008-08 EN 843-1:2006 (E) 3 Foreword This document (EN 843-1:2006) has been prepared by Technical Committee CEN/TC 184 “Advanced technical ceramics”,

17、 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 text or by endorsement, at the latest by June 2007, and conflicting national standards shall be withdrawn at the latest by June 2007. This document

18、 supersedes EN 843-1:1995. EN 843 Advanced technical ceramics Mechanical properties of monolithic ceramics at room temperature comprises six parts: Part 1: Determination of flexural strength Part 2: Determination of Youngs modulus, shear modulus and Poissons ratio Part 3: Determination of subcritica

19、l crack growth parameters from constant stressing rate flexural strength tests Part 4: Vickers, Knoop and Rockwell superficial hardness Part 5: Statistical analysis Part 6: Guidance for fractographic investigation At the time of publication of this Revision of Part 1, Part 6 was available as a Techn

20、ical Specification. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Irelan

21、d, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. DIN EN 843-1:2008-08 EN 843-1:2006 (E) 4 1 Scope This part of EN 843 specifies methods for determining the nominal flexural strength of a

22、dvanced monolithic technical ceramic materials at ambient temperature. The available loading geometries are three- and four-point flexure, using rectangular section test pieces of two prescribed geometries: 20 mm support span (A) and 40 mm support span (B). NOTE This part of EN 843 differs from ISO

23、14704 (see Bibliography) in respect of span A (not included in the ISO version), the absence of the 30 mm span option, and the required use of a fully articulating test jig. The test applies to materials with grain size less than 200 m. The test prescribes four categories of surface finish applied t

24、o the test pieces: I: as-fired or annealed after machining; II: standard finishing by grinding; III: standard finishing by lapping/polishing; IV: machined using agreed grinding procedures and material removal rates. 2 Normative references The following referenced documents are indispensable for the

25、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 623-4, Advanced technical ceramics Monolithic ceramics General and textural properties Part 4: Determinatio

26、n of surface roughness EN 843-5, Advanced technical ceramics Mechanical properties of monolithic ceramics at room temperature Part 5: Statistical analysis EN ISO 7500-1, Metallic materials Verification of static uniaxial testing machines Part 1: Tension/compression testing machines Verification and

27、calibration of the force-measuring system (ISO 7500-1:2004) EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:2005) ISO 3611, Micrometer callipers for external measurement ISO 4677-1, Atmospheres for conditioning and testing Determinatio

28、n of relative humidity Part 1: Aspirated psychrometer method ISO 4677-2, Atmospheres for conditioning and testing Determination of relative humidity Part 2: Whirling psychrometer method DIN EN 843-1:2008-08 EN 843-1:2006 (E) 5 3 Terms and definitions For the purposes of this document, the following

29、terms and definitions apply. 3.1 nominal flexural strength maximum nominal stress supported by the material at the instant of failure when loaded in linear elastic bending 3.2 three-point flexure means of bending a beam test piece whereby the test piece is supported on bearings near its ends and a c

30、entral force is applied 3.3 four-point flexure means of bending a beam test piece whereby the test piece is supported on bearings near its ends and is loaded equally at two positions symmetrically disposed about the centre of the supported span 3.4 quarter-point flexure four-point flexure (3.3) wher

31、ein the loading bearings are each one-quarter of the support span from the support bearings 4 Significance and use This test is intended to be used for material development, quality control, characterization and design data acquisition purposes. The strength level determined by the test is calculate

32、d on the basis of linear elastic bending of a thin beam on the assumption that the material being tested is elastically homogeneous and isotropic, and shows linear (Hookean) stress-strain behaviour. The result obtained from a strength test is determined by a large number of factors associated with t

33、he microstructure of the material, the surface finishing procedure applied in preparation of the test pieces, the size and shape of the test piece, the mechanical function of the testing apparatus, the rate of load application and the relative humidity of the ambient atmosphere. As a consequence of

34、the brittle nature of ceramics, there is usually a considerable range of results obtained from a number of nominally identical test pieces. These factors combined mean that caution in the interpretation of test results is required. For many purposes, and as described in this European Standard, the r

35、esults of strength tests may be described in terms of a mean value and a standard deviation. Further statistical evaluation of results is required for design data acquisition, and may be desirable for other purposes (see EN 843-5). This method places closely defined restrictions on the size and shap

36、e of the test piece and on the function of the test apparatus in order to minimize the errors that can arise as a consequence of the test method. NOTE The basis for the choice of dimensions and tolerances of test pieces and of the requirements of the test-jig may be found in reference 4. All other t

37、est factors are required to be stated in the test report (see Clause 9) in order to allow inter-comparison of material behaviours. It is not possible to rigorously standardize particular surface finishes, since these are not absolutely controllable in mechanical terms. The inclusion of a standard gr

38、inding procedure (see 6.3) as one of the surface finish options in this method is intended to provide a means of obtaining a minimum amount of residual grinding damage in the test material. The extrapolation of flexural strength data to other geometries of stressing, to multiaxial stressing, to othe

39、r rates of stressing or to other environments should be viewed with caution. DIN EN 843-1:2008-08 EN 843-1:2006 (E) 6 The origin of fracture in a flexural test can be a valuable guide to the nature and position of strength-limiting defects. Fractography of test pieces is highly recommended. In parti

40、cular, the test may identify fracture origins as being edge defects (caused by edge preparation), surface defects (caused by surface preparation), or internal defects (caused by manufacturing inhomogeneities such as pores, large grains, impurity concentrations etc.). Not all advanced monolithic tech

41、nical ceramics are amenable to clear fractography. 5 Apparatus 5.1 Test jig The test jig shall be capable of either three-point or four-point flexure and functioning as specified below in order to minimize misalignments, twist and frictional forces applied to the test piece. NOTE 1 The precise test

42、jig design is not specified, only the function. Schematic arrangements of the test jig function are shown in Figure 1 a) for three-point flexure, and Figure 1 b) for four-point flexure. The test piece shall be supported on two bearing edges perpendicular to its length. The outer support bearing edge

43、s shall be parallel rollers of diameter approximately 1,5 times the test piece thickness. Diameters of between 2,2 mm and 2,5 mm (for span A - see 6.2) or between 4,5 mm and 5,0 mm (for span B - see 6.2) are recommended. The rollers shall be capable of rolling outward on flat support surfaces. One o

44、f the rollers shall additionally be capable of rotating about an axis parallel to the length of the test piece such that torsional loading is minimized. The two rollers shall be positioned initially with their centres 20 mm 0,5 mm apart (span A) or 40 mm 0,5 mm apart (span B) with their axes paralle

45、l to 0,2 mm over their lengths ( 12 mm). See Figure 2. For three-point flexure, a third roller shall be located at the mid-point between and parallel to the two support rollers (Figures 2 a) and 2 c). This roller shall have the same diameter as the support rollers and shall be similarly free to rota

46、te about an axis parallel to the length of the test piece. Its position relative to the midpoint between the support rollers shall be better than 0,2 mm, measured to the nearest 0,1 mm in a direction parallel to the length of the test piece using the travelling microscope or other suitable device (s

47、ee 5.4). For four-point flexure, two loading rollers shall be located at the quarter points (see 3.4), i.e. with inner spans 10 mm 0,2 mm (outer span A) or 20 mm 0,2 mm (outer span B), and shall be free to roll inwards (Figures 2 b) and 2 d). As with the three-point apparatus, the two rollers shall

48、also be free to rotate separately about an axis parallel to the length of the test piece to allow alignment. The loading rollers shall be symmetrically positioned to within 0,1 mm. The distances between the centres of the support rollers and adjacent loading rollers shall be measured to the nearest

49、0,1 mm along the length of the test piece perpendicular to the direction of loading, using the travelling microscope or other suitable device (see 5.4). The arrangement for loading shall ensure that equal forces are applied to the two loading rollers. The separation of the centres of the rollers in their starting positions shall be measured to the nearest 0,1 mm with the travelling microscope (see 5.3.2) or other suitable device. The rollers shall be made from hardened steel or other hard material wi