07-30165197-DC.pdf
a Date: 25 April 2007 Origin: International Latest date for receipt of comments: 31 July 2007 Project no.: 2007/01029 Responsible committee: RPI/13 Advanced technical ceramics Interested committees: Title: Draft BS ISO 23146 Fine ceramics (advanced ceramics, advanced technical ceramics) - Test methods for fracture toughness of monolithic ceramics - Single-edge V-notch beam (SEVNB) method Supersession information: If this document is published as a standard, the UK implementation of it will supersede NONE and partially supersede. NONE If you are aware of a current national standard which may be affected, please notify the secretary (contact details below). WARNING: THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A BRITISH STANDARD. THIS DRAFT IS NOT CURRENT BEYOND 31 July 2007. This draft is issued to allow comments from interested parties; all comments will be given consideration prior to publication. No acknowledgement will normally be sent. 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DRAFT INTERNATIONAL STANDARD ISO/DIS 23146 © International Organization for Standardization, 2007 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION ISO/TC 206 Voting begins on: 2007-04-23 Secretariat: JISC Voting terminates on: 2007-09-23 Fine ceramics (advanced ceramics, advanced technical ceramics) Test methods for fracture toughness of monolithic ceramics Single-edge V-notch beam (SEVNB) method Céramiques techniques Méthodes d'essai pour la détermination de la ténacité à la rupture des céramiques monolithiques Méthode sur éprouvette à entaille en V sur une seule face (Méthode SEVNB) ICS 81.060.30 In accordance with the provisions of Council Resolution 15/1993 this document is circulated in the English language only. Conformément aux dispositions de la Résolution du Conseil 15/1993, ce document est distribué en version anglaise seulement. To expedite distribution, this document is circulated as received from the committee secretariat. 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Licensed Copy: London South Bank University, London South Bank University, Wed May 16 04:17:02 GMT+00:00 2007, Uncontrolled Copy, (c) BSI ISO/DIS 23146 © ISO 2007 All rights reserved iii Contents Page Foreword iv Introductioniv 1 Scope1 2 Normative references1 3 Terms and definitions.1 4 Principle1 5 Apparatus.2 5.1 Razor blades 2 5.2 Diamond paste.2 5.3 Lubricant 2 5.4 Test piece support.2 5.5 Flexural strength test fixture2 5.6 Mechanical testing machine.3 5.7 Ultrasonic cleaning bath.3 5.8 Micrometer .3 5.9 Microscope.3 5.10 Notch measuring device.3 5.11 Drying oven3 5.12 Diamond slitting saw.3 6 Test piece preparation4 6.1 Number of test pieces.4 6.2 Test-piece dimensions4 6.3 Preparing the V-notch by hand4 6.4 Preparing the V-notches by machine (optional).7 6.5 Determination of notch root radius .7 7 Test procedure.8 7.1 Dimensions of test-piece8 7.2 Flexural strength test8 7.3 Measurement of notch depth .9 7.4 Calculation of fracture toughness.9 8 Precision and bias.11 9 Test report11 Annex A (informative) Notch honing by machine13 Annex B (informative) Interlaboratory evaluation of the SEVNB fracture toughness test procedures.14 Annex C (informative) Corrections for effective crack length greater than notch depth16 Bibliography17 Licensed Copy: London South Bank University, London South Bank University, Wed May 16 04:17:02 GMT+00:00 2007, Uncontrolled Copy, (c) BSI ISO/DIS 23146 iv © ISO 2007 All rights reserved Foreword ISO (the International Organization for Standardization) is a 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 represented 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 drafted 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 Standard 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 Technical Committee ISO/TC 206, Fine ceramics. This second/third/. edition cancels and replaces the first/second/. edition (), clause(s) / subclause(s) / table(s) / figure(s) / annex(es) of which has / have been technically revised. Licensed Copy: London South Bank University, London South Bank University, Wed May 16 04:17:02 GMT+00:00 2007, Uncontrolled Copy, (c) BSI DRAFT INTERNATIONAL STANDARD ISO/DIS 23146 © ISO 2007 All rights reserved 1 1 Scope This ISO standard describes a method for the determination of the fracture toughness of advanced technical ceramics. The procedure makes use of V-notched bars, which are loaded in 4-point bending until failure. It is applicable to ceramics with a grain size or major microstructural feature size larger than about 1 µm. The use of this standard for yttria tetragonal zirconia polycrystal material (Y-TZP) is not recommended. The method may 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 references This standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and in the publications listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies. ISO 3611, Micrometer callipers for external measurement ISO 14704, Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for flexural strength of monolithic ceramics at room temperature ISO 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) method 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 15732 apply to this standard. 4 Principle This 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 either a manual method or a simple machine. Under well-controlled conditions a notch tip radius in the range of 1 µm to 20 µm 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 fracture toughness values very close to those of other methods such as the single-edge pre-cracked 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 sequence. The method has advantages 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 Fine ceramics (advanced ceramics, advanced technical ceramics) Test methods for fracture toughness of monolithic ceramics Single-edge V-notch beam (SEVNB) method Licensed Copy: London South Bank University, London South Bank University, Wed May 16 04:17:02 GMT+00:00 2007, Uncontrolled Copy, (c) BSI ISO/DIS 23146 2 ©
