1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationDD CEN/TS 843-9:2010Advanced technical ceramics Mechanical properties ofmonolithic ceramics at roomtemperaturePart 9: Method of test for edge-chipresistanceDD CEN/TS 843-9:2010 D
2、RAFT FOR DEVELOPMENTNational forewordThis Draft for Development is the UK implementation of CEN/TS843-9:2010.This publication is not to be regarded as a British Standard.It is being issued in the Draft for Development series of publicationsand is of a provisional nature. It should be applied on this
3、provisional basis, so that information and experience of its practicalapplication can be obtained.Comments arising from the use of this Draft for Developmentare requested so that UK experience can be reported to theinternational organization responsible for its conversion toan international standard
4、. A review of this publication willbe initiated not later than 3 years after its publication by theinternational organization so that a decision can be taken on itsstatus. Notification of the start of the review period will be made inan announcement in the appropriate issue of Update Standards.Accor
5、ding to the replies received by the end of the review period,the responsible BSI Committee will decide whether to support theconversion into an international Standard, to extend the life of theTechnical Specification or to withdraw it. Comments should be sentto the Secretary of the responsible BSI T
6、echnical Committee at BritishStandards House, 389 Chiswick High Road, London W4 4AL.The UK participation in its preparation was entrusted to TechnicalCommittee RPI/13, Advanced technical ceramics.A list of organizations represented on this committee can beobtained on request to its secretary.This pu
7、blication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2010ISBN 978 0 580 68823 2ICS 81.060.30Compliance with a British Standard cannot confer immunity fromlegal obligations.This Draft for Development was published under
8、 the authority ofthe Standards Policy and Strategy Committee on 30 September 2010.Amendments issued since publicationDate Text affectedDD CEN/TS 843-9:2010TECHNICAL SPECIFICATION SPCIFICATION TECHNIQUE TECHNISCHE SPEZIFIKATION CEN/TS 843-9 August 2010 ICS 81.060.30 English Version Advanced technical
9、 ceramics - Mechanical properties of monolithic ceramics at room temperature - Part 9: Method of test for edge-chip resistance Cramiques techniques avances - Proprits mcaniques des cramiques monolithiques temprature ambiante - Partie 9: Mthode dessai de rsistance lcaillage des bords Hochleistungsker
10、amik - Mechanische Eigenschaften monolithischer Keramik bei Raumtemperatur - Teil 9: Prfverfahren zur Bestimmung der Kantenbestndigkeit gegen Abplatzung This Technical Specification (CEN/TS) was approved by CEN on 25 April 2010 for provisional application. The period of validity of this CEN/TS is li
11、mited initially to three years. After two years the members of CEN will be requested to submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard. CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and
12、 to make the CEN/TS available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached. CEN members are the national stan
13、dards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and
14、United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TS 843-
15、9:2010: EDD CEN/TS 843-9:2010CEN/TS 843-9:2010 (E) 2 Contents Page Foreword 31 Scope 42 Normative references 43 Terms and definitions .44 Principle and use .45 Method A: Direct force application 55.1 Apparatus .55.2 Test piece .65.3 Test procedure .75.4 Calculation of results 76 Method B: Sliding fo
16、rce application 86.1 Apparatus .86.2 Test piece .96.3 Test procedure .96.4 Calculation of results 97 Interferences . 108 Report 10Bibliography . 12DD CEN/TS 843-9:2010CEN/TS 843-9:2010 (E) 3 Foreword This document (CEN/TS 843-9:2010) has been prepared by Technical Committee CEN/TC 184 “Advanced tech
17、nical ceramics”, the secretariat of which is held by BSI. 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 responsible for identifying any or all such patent rights. According to the CEN/CENELEC
18、 Internal Regulations, the national standards organizations of the following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithua
19、nia, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. DD CEN/TS 843-9:2010CEN/TS 843-9:2010 (E) 4 1 Scope This Technical Specification describes requirements and methods for undertaking tests to determine the re
20、sistance of the edges of brittle ceramic materials to be damaged by chipping or flaking. It is limited to homogeneous monolithic ceramics with flat surfaces and straight sharp or chamfered edges. 2 Normative references The following referenced documents are indispensable for the application of this
21、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: Determination of surface rou
22、ghness 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) EN ISO 17025, General requirements for the competence of testing and calibration labor
23、atories (ISO/IEC 17025:2005) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 chip or flake detached piece of material from the edge of a component or test piece 3.2 edge chipping or edge flaking process of producing a chip or flake from the e
24、dge of a component or test piece 3.3 edge chip resistance measure of the resistance of the edge of a component or test piece to chipping or flaking determined by dividing the force applied by the maximum thickness of the flake or the distance of the centre of the applied force from the edge at which
25、 it is formed NOTE The term edge toughness has an equivalent meaning. 4 Principle and use Localised loading near the edge of a ceramic component can lead to spalling of the edge, and hence to loss of function of the component. The test methods in this standard provide means of quantifying the resist
26、ance of a ceramic product to edge damage, either by applying a monotonically increasing force to an indenter positioned a fixed distance from the edge (Method A), or by applying a predetermined force to an indenter positioned remotely from the edge, and dragging it towards the edge (Method B). In th
27、e case of method A, the force required to cause an edge flake to form at a pre-determined position is recorded; while in the case of Method B, the distance from the edge at which the flake is formed under a pre-determined force is measured. DD CEN/TS 843-9:2010CEN/TS 843-9:2010 (E) 5 In both cases (
28、see Figure 1), the force applied, F, divided by the distance from the edge at which the flake is formed, d, commonly known as the edge toughness, is then a measure of edge chip resistance. This test can also be used to determine the effectiveness of chamfers placed on edges. A chamfer prevents direc
29、t loading near the edge. The size of the chamfer required for the component to withstand a given near-edge loading can be determined by this test. dFFw(a) (b) Key: F Indenter applying force normal to plane d maximum flake depth into bulk w maximum flake width on face Figure 1 Schematic of indentatio
30、n near an edge using a hard indenter (a) cross-sectional view of a flake formed at an edge, and (b) flake shape viewed from edge side 5 Method A: Direct force application 5.1 Apparatus 5.1.1 General The force required shall be applied by any suitable mechanical testing machine which operates either
31、in a constant displacement rate mode or in a constant force increase rate mode. The machine shall drive an indenter (5.1.4) into the surface of a component or test piece at a pre-determined location near the edge until the flake forms. NOTE The mechanism of flake formation is thought be the preferre
32、d extension of those radial cracks emanating from the indentation which are roughly parallel with the edge. Owing to the lack of elastic constraint near the edge, these propagate sideways and into the material to form a shell-shaped crack, which once past a certain size becomes unstable and forms a
33、detached flake. DD CEN/TS 843-9:2010CEN/TS 843-9:2010 (E) 6 5.1.2 Test machine A mechanical testing machine shall be used, which is 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 test jig at any po
34、int in time, and preferably of capturing the peak force applied. 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 1 % of the maximum load employed. The calibration shall have
35、 recently been checked. 5.1.3 Test piece holder The test-piece shall be held in a clamping device which enables the component or test piece to be held in a fixed position in the testing machine (Figure 2). Preferably the clamping device incorporates two orthogonal means of adjusting position so that
36、 the location of the indenter (5.1.4) can be adjusted precisely, e.g. using an X-Y micrometer screw table which can be locked when indenting. NOTE It is convenient to be able to view the indentation position by sighting normal to the indentation surface using a microscope or other suitable device, e
37、.g. by moving the indenter out of the line of sight. Such an arrangement permits the indenter to be positioned an exact distance from the edge of the test piece. 12341 Load cell 2 Indenter 3 Test piece or test items 4 X-Y lockable table Figure 2 Schematic of indentation technique for method A 5.1.4
38、Indenter A sharp or a blunt diamond indenter shall be used for this test, as appropriate to requirements. NOTE It is recommended that for reliability, especially in high force tests, a Rockwell geometry diamond (see EN 843-4) with a tip radius or 0,2 mm and manufactured from polycrystalline diamond
39、is employed. If a Vickers or Knoop diamond is used, ensure that the diagonal length of the indentation is consistently aligned with the edge of the test piece. 5.2 Test piece The principal requirement is that the component or test piece to be tested has a flat surface which is capable of being rigid
40、ly mounted with its normal parallel to the direction of indentation. NOTE 1 Any edge profile may be tested, although square edges are more appropriate for materials comparison purposes. DD CEN/TS 843-9:2010CEN/TS 843-9:2010 (E) 7 NOTE 2 The surface and edge condition of the test piece is not critica
41、l for this test unless the machining damage is severe, in which case the damage introduced can interfere with the crack development process. 5.3 Test procedure Position the component or test piece in the test piece holder (5.1.3) and clamp it into position. Adjust the position of the test piece rela
42、tive to the indenter to the required indentation distance from the edge. NOTE 1 The distance of indentation from the edge may be chosen arbitrarily. It is recommended that a distance of approximately 0,5 mm is used as a starting point with an unknown material. Depending on the material behaviour, th
43、e distance of indentation from the edge can then be either increased or decreased according to requirements. Apply a force to the indenter with the test machine at a displacement rate of no more than 0,5 mm/min and record the peak force at which the flake is produced. Record the distance of indentat
44、ion from the edge to the nearest 0,1 mm. NOTE 2 The distance from the edge may be recorded via the positioning of the test piece under the indenter, or may be measured after the test using a travelling microscope or other suitable device measuring to the nearest 0,01 mm. Retract the indenter and mov
45、e the test-piece to a new indentation position at the same distance from the edge. If indenting on the same edge, ensure that there is no overlap of flakes produced, i.e. the lateral separation of indentation positions should be greater than the flake width (see Figure 1 (w), or typically greater th
46、an 10 times the distance of indentation from the edge (see Figure 1 (d). Repeat the procedure. Make at least 10 tests. 5.4 Calculation of results For each flake produced, calculate the edge chip resistance, ReA, by dividing the maximum flaking force, F, expressed in N, by the distance of indentation
47、 from the edge, d, expressed in mm. dFReA= (1) Compute the average value of ReA=nieAieAnRR1/ (2) where n is the number of tests. Compute the standard deviation sd of eAR : )1()(12=nnRRsdnieAieA(3) DD CEN/TS 843-9:2010CEN/TS 843-9:2010 (E) 8 6 Method B: Sliding force application 6.1 Apparatus 6.1.1 G
48、eneral This method requires an ability to apply a constant force to an indenter contact a test surface normally, and then to move the test surface under the indenter such that the contact point moves perpendicularly towards a free edge. NOTE 1 It is easiest to conduct this test in a purpose made scr
49、atch tester (see EN 1071-3), but it may also be conducted in a universal testing machine using an appropriately designed fixture. NOTE 2 As the indenter is slid across the surface, cracks roughly perpendicular to the direction of sliding are produced behind the sliding point. When the contact point nears the edge of the test piece, the loss of edge constraint eventually permits one of these cracks to propagate and to result in edge flake formation. 6.1.2 Test machine The preferred test machine is a s
