1、BSI Standards PublicationBS EN ISO 23146:2016Fine ceramics (advancedceramics, advanced technicalceramics) Test methodsfor fracture toughness ofmonolithic ceramics Single-edge V-notch beam (SEVNB)method (ISO 23146:2012)BS EN ISO 23146:2016 BRITISH STANDARDNational forewordThis British Standard is the
2、 UK implementation of EN ISO23146:2016. It is identical to ISO 23146:2012. It supersedes DD CEN/TS 14425-5:2004 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee RPI/13, Advanced technical ceramics.A list of organizations represented on this committee can
3、 beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2016. Published by BSI StandardsLimited 2016ISBN 978 0 580 91173 6ICS 81.060.30Complianc
4、e with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 May 2016.Amendments issued since publicationDate Text affectedEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 23
5、146 April 2016 ICS 81.060.30 Supersedes CEN/TS 14425-5:2004English Version Fine ceramics (advanced ceramics, advanced technical ceramics) - Test methods for fracture toughness of monolithic ceramics - Single-edge V-notch beam (SEVNB) method (ISO 23146:2012) Cramiques techniques - Mthodes dessai pour
6、 la dtermination de la tnacit la rupture des cramiques monolithiques - Mthode sur prouvette entaille en V sur une seule face (Mthode SEVNB) (ISO 23146:2012) Hochleistungskeramik - Prfverfahren zur Bestimmung der Bruchzhigkeit monolithischer Keramik - Verfahren fr Biegeproben mit V-Kerb (SEVNB-Verfah
7、ren) (ISO 23146:2012) This European Standard was approved by CEN on 18 March 2016. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and
8、 bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC 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 translation under the r
9、esponsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav
10、 Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE N
11、ORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 23146:2016 EBS EN ISO 23146:2016EN ISO 23146:2016 (E) 3 European
12、foreword The text of ISO 23146:2012 has been prepared by Technical Committee ISO/TC 206 “Fine ceramics” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 23146:2016 by Technical Committee CEN/TC 184 “Advanced technical ceramics” the secretariat of which is
13、 held by DIN. 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 October 2016, and conflicting national standards shall be withdrawn at the latest by October 2016. Attention is drawn to the possibili
14、ty that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes CEN/TS 14425-5:2004. According to the CEN-CENELEC Internal Regulations, the national standards o
15、rganizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembou
16、rg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 23146:2012 has been approved by CEN as EN ISO 23146:2016 without any modification. BS EN ISO 23146:2016ISO 23146:2012(E) ISO 20
17、12 All rights reserved iiiContents PageForeword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 Apparatus . 26 Test piece preparation 36.1 Number of test pieces . 36.2 Test-piece dimensions 46.3 Preparing the V-notch by hand . 46.4 Preparing the V-notches by machine (o
18、ptional) 76.5 Determination of notch-root radius . 77 Test procedure 87.1 Dimensions of test piece . 87.2 Flexural-strength test 87.3 Measurement of notch depth 97.4 Calculation of fracture toughness . 98 Precision and bias 119 Test report 11Annex A (informative) Notch honing by machine 12Annex B (i
19、nformative) Interlaboratory evaluation of the SEVNB fracture toughness test procedures .14Annex C (informative) Corrections for effective crack length greater than notch depth 16Bibliography .17BS EN ISO 23146:2016ISO 23146:2012(E)ForewordISO (the International Organization for Standardization) is a
20、 worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represente
21、d on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are draft
22、ed in accordance with the rules given in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Stand
23、ard requires approval by at least 75 % of the member bodies casting a vote.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 23146 was prepared by T
24、echnical Committee ISO/TC 206, Fine ceramics.This second edition cancels and replaces the first edition (ISO 23146:2008), of which it constitutes a minor revision.iv ISO 2012 All rights reservedBS EN ISO 23146:2016INTERNATIONAL STANDARD ISO 23146:2012(E)Fine ceramics (advanced ceramics, advanced tec
25、hnical ceramics) Test methods for fracture toughness of monolithic ceramics Single-edge V-notch beam (SEVNB) method1 ScopeThis International Standard specifies a method for the determination of the fracture toughness of advanced technical ceramics. The procedure makes use of single-edge V-notched ba
26、rs, which are loaded in four-point bending until failure. It is applicable to monolithic ceramics with a grain size or major microstructural feature size larger than about 1 m.The use of this International Standard for yttria tetragonal zirconia polycrystal material (Y-TZP) is not recommended. The m
27、ethod might also be unsuitable for some other very tough or soft ceramics in which a sharp crack does not form at the root of the V-notch.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited appl
28、ies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 3611, Geometrical product specifications (GPS) Dimensional measuring instruments; Micrometers for external measurements Design and metrological characteristicsISO 7500-1, Metallic materi
29、als Verification of static uniaxial testing machines Part 1: Tension/compression testing machines Verification and calibration of the force-measuring systemISO 14704, Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for flexural strength of monolithic ceramics at room tempe
30、ratureISO 15732, Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for fracture toughness of monolithic ceramics at room temperature by single edge precracked beam (SEPB) method3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 1
31、5732 apply.4 PrincipleThis method of conducting a fracture toughness test is based on the preparation and fracture of bar test pieces in which a sharp-tipped notch is machined. Using the technique of a reciprocating razor blade and diamond paste, a narrow notch can be honed into a test piece using e
32、ither a manual method or a simple machine. Under well-controlled conditions, a notch-tip radius in the range of 1 m to 20 m can be prepared depending on the grain size of the test material. For many materials, this is a close approximation to a sharp crack, and the method has been found to give frac
33、ture toughness values very close to those of other methods such as the single-edge precracked beam method (ISO 15732) or the surface crack in flexure method (ISO 18756), provided that a sharp crack forms at the root of the notch either during its preparation or during the subsequent fracture sequenc
34、e. The method has the advantage of simplicity of notch production compared with using a sharp-tipped diamond saw or a diamond impregnated wire in which the tip radius is normally greater than 50 m. The method is often ISO 2012 All rights reserved 1BS EN ISO 23146:2016ISO 23146:2012(E)easier to under
35、take compared with other methods of precracking and is applicable to a wider range of materials outside the scope of these methods.The method has been extensively researched (see the Bibliography) and has been evaluated in an ESIS (European Structural Integrity Society)/VAMAS (Versailles Agreement o
36、n Advanced Materials and Standards) round robin, the results of which are summarized in Annex B. This recommended practice is based upon the ESIS/VAMAS SEVNB round robin.The method may have some limitations for materials with grain sizes of less than 1 m, for which the assumption that the notch appr
37、oximates to a sharp crack may not be valid (see Annex C). Users should strive to minimize the notch-root radius in the test pieces. This International Standard places a provisional criterion that the notch-root radius should be similar to or less than twice the average grain size of the material.The
38、 method is complementary to other methods of measuring fracture toughness described in ISO 15732 (single-edge precracked beam method), ISO 18756 (surface crack in flexure method), and ISO 24370 (chevron notch method); see the Bibliography.5 Apparatus5.1 Ordinary razor blades, preferably with a suppo
39、rt along one edge but alternatively inserted in a suitable holder.NOTE 1 Razor blades thinner than about 0,2 mm are not ideal for this task unless stiffened by a support, such as by gluing or screwing between two steel plates, leaving only about 2 mm of edge showing. A razor blade with a tip angle o
40、f 30 or smaller is ideal.NOTE 2 Although it is possible to machine the notches entirely by hand, the use of a simple device in which the test pieces are mounted and in which a razor blade primed with diamond paste is moved in a reciprocating motion across the mounted test pieces has a distinct advan
41、tage, as this provides controlled loading and directional stability to the razor blade, and sharper notches are produced. An example is shown in Annex A.5.2 Metallographic diamond paste, in a viscous organic carrier and of fine grain size, typically 1 m to 3 m.5.3 Lubricant, a light lubricating oil
42、for lubricating the razor blade, e.g. clock oil.5.4 Test piece support, consisting of a flat plate or other suitable device for mounting test pieces during notch honing.5.5 Flexural-strength test fixture, preferably a four-point flexural-strength test fixture operating in accordance with the require
43、ments of ISO 14704, i.e. either 1/4-point flexure (preferred) or 1/3-point flexure. Alternatively, a three-point flexural-strength test jig may also be used, but the alignment of the V-notch with the central loading roller is more critical.The test piece is supported on two bearing edges perpendicul
44、ar to its length. The outer-support bearing edges shall be parallel rollers of diameter 5,0 mm 0,2 mm and shall be capable of rolling outward on flat support surfaces. Preferably, one of the rollers shall additionally be capable of rotating about an axis parallel to the length of the test piece such
45、 that torsional loading is minimised. The two rollers shall be positioned initially with their centres 40,0 mm 0,5 mm (1/4-point flexure) or 30 mm 0,5 mm (1/3-point flexure) apart with their axes parallel to within 1. The separation of the centres of the rollers in their starting positions shall be
46、measured to the nearest 0,1 mm with a travelling microscope. The rollers shall be made from hardened steel or other hard material with a hardness greater than 40 HRC (Rockwell C-scale). The rollers shall have a smooth burr-free surface finish with roughness less than 0,5 m Ra and shall have a diamet
47、er uniform to 0,02 mm.For four-point flexure, the two loading rollers are located at the 1/4-points (or 1/3-points), with an inner span of 20 mm 0,2 mm (or 10 mm 0,2 mm for 1/3-point flexure) and are free to roll inwards. The 2 ISO 2012 All rights reservedBS EN ISO 23146:2016ISO 23146:2012(E)rollers
48、 are free to rotate separately about an axis parallel to the length of the test piece to allow alignment. For three-point flexure, the single loading roller, which need not rotate, shall be positioned centrally between the outer-support rollers. The distances between the rollers shall be measured to
49、 the nearest 0,1 mm along the length of the specimen perpendicular to the direction of loading, using a travelling microscope or other suitable device. The loading rollers in four-point flexure shall be symmetrically positioned to within 0,1 mm. The arrangement for loading shall ensure that equal forces are applied to the two loading rollers. The single loading roller in three-point flexure shall be centrally located to within 0,2 mm.5.6 Mechanical testing machine, capable of applying a force at a constant
