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1、DRAFT FOR DEVELOPMENT DD CEN/TS 843-6:2004 Advanced technical ceramics Monolithic ceramics Mechanical properties at room temperature Part 6: Guidance for fractographic investigation ICS 81.060.30 ? Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 06:04:03 GMT+00:
2、00 2006, Uncontrolled Copy, (c) BSI DD CEN/TS 843-6:2004 This Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 17 August 2004 BSI 17 August 2004 ISBN 0 580 44300 0 National foreword This Draft for Development is the official English language v
3、ersion of CEN/TS 843-6:2004. This publication is not to be regarded as a British Standard. It is being issued in the Draft for Development series of publications and is of a provisional nature because it is considered that further experience is required in its application before it is converted to a
4、 European and hence British Standard. It should be applied on this provisional basis, so that information and experience of its practical application may be obtained. Comments arising from the use of this Draft for Development are requested so that UK experience can be reported to the European organ
5、ization responsible for its conversion to a European Standard. A review of this publication will be initiated 2 years after its publication by the European organization so that a decision can be taken on its status at the end of its 3-year life. Notification of the start of the review period will be
6、 made in an announcement in the appropriate issue of Update Standards. According to the replies received by the end of the review period, the responsible BSI Committee will decide whether to support the conversion into a European Standard, to extend the life of the Technical Specification or to with
7、draw it. Comments should be sent in writing to the Secretary of BSI Technical Committee RPI/13, Advanced technical ceramics, at British Standards House, 389 Chiswick High Road, London W4 4AL, giving the document reference and clause number and proposing, where possible, an appropriate revision of th
8、e text. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “Internat
9、ional Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. Summary of pages This document comprises a front cover, an inside front cover, the CEN/TS title page, pages 2 to 44, an inside back cover and a back cover. The BSI
10、 copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 06:04:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI TECHNICAL SPEC
11、IFICATION SPCIFICATION TECHNIQUE TECHNISCHE SPEZIFIKATION CEN/TS 843-6 June 2004 ICS 81.060.30 English version Advanced technical ceramics - Monolithic ceramics. Mechanical properties at room temperature - Part 6: Guidance for fractographic investigation Cramiques techniques avances - Cramiques mono
12、lithiques -Proprits mcaniques temprature ambiante - Partie 6: Guide pour lanalyse fractographique Hochleistungskeramik - Monolithische Keramik - Mechanische Eigenschaften bei Raumtemperatur - Teil 6: Leitlinie fr die fraktographische Untersuchung This Technical Specification (CEN/TS) was approved by
13、 CEN on 17 November 2003 for provisional application. The period of validity of this CEN/TS is limited 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. C
14、EN members are required to announce the existence of this CEN/TS in the same way as for an EN and 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 abo
15、ut the possible conversion of the CEN/TS into an EN is reached. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
16、Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2004 CENAll rights of exploitation in any form and by any m
17、eans reserved worldwide for CEN national Members. Ref. No. CEN/TS 843-6:2004: E Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 06:04:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI CEN/TS 843-6:2004 (E) 2 ContentsPage Foreword.3 1Scope4 2Normative references4 3Te
18、rms and definitions.4 3.1General terms4 3.2Terms classifying inherently volume-distributed fracture origins 5 3.3Terms classifying inherently surface-distributed fracture origins5 3.4Terms classifying features on fracture surfaces.6 4Significance and use.6 5Apparatus.7 5.1Preparation and cleaning fa
19、cilities7 5.2Observational facilities.7 6Recommended procedure9 6.1Outline9 6.2Specimen storage and cleaning of fracture surfaces .9 6.3Visual inspection.9 6.4Optical microscope examination.10 6.5Identification of major fracture surface features.10 6.6Scanning electron microscope examination12 6.7Id
20、entification of fracture origin12 6.8Identification of chemical inhomogeneity at fracture origin 13 6.9Drawing conclusions13 7Report.13 Annex A (informative) Crack patterns in ceramic bodies.14 Annex B (informative) Examples of general features of fracture surfaces.17 Annex C (informative) Examples
21、of procedure for fracture origin identification.19 C.1Single large pores.20 C.2Agglomerates 22 C.3Large grains.24 C.4Compositional inhomogeneities26 C.5Delaminations28 C.6Handling damage 30 C.7Machining damage31 C.8Oxidation pitting33 C.9Complex origins35 C.10No obvious origins36 Annex D (informativ
22、e) Use of fracture mechanical information to aid fractography.37 D.1Fracture stress and origin size37 D.2Fracture stress and fracture mirror size.40 Annex E (informative) Example layout of reporting pro-forma.42 Bibliography .44 Licensed Copy: London South Bank University, London South Bank Universi
23、ty, Tue Dec 12 06:04:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI CEN/TS 843-6:2004 (E) 3 Foreword This document CEN/TS 843-6:2004 has been prepared by Technical Committee CEN/TC 184 “Advanced technical ceramics”, the secretariat of which is held by BSI. This document has been prepared under a mand
24、ate given to CEN by the European Commission and the European Free Trade Association. Annexes A to E are informative. This document includes a Bibliography. EN 843 Advanced technical ceramics Monolithic ceramics Mechanical properties at room temperature consists of six parts: Part 1: Determination of
25、 flexural strength Part 2: Determination of elastic moduli Part 3: Determination of subcritical crack growth parameters from constant stressing rate flexural strength tests Part 4: Vickers, Knoop and Rockwell superficial hardness tests Part 5: Statistical analysis Part 6: Guidance for fractographic
26、investigation At the time of publication of this Technical Specification, Part 1 is a European Standard, while Parts 2 to 5 are European Prestandards. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to announce this Technic
27、al Specification: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom Licensed Co
28、py: London South Bank University, London South Bank University, Tue Dec 12 06:04:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI CEN/TS 843-6:2004 (E) 4 1 Scope This Technical Specification contains guidelines to be adopted when evaluating the appearance of the fracture surface of an advanced technica
29、l ceramic. The purpose in undertaking this procedure can be various, for example, for material development or quality assessment, to identify normal or abnormal causes of failure, or as a design aid. NOTE Not all advanced technical ceramics are amenable to fractography. In particular, coarse-grained
30、 ceramics can show such rough surfaces that identifying the fracture origin may be impossible. Similarly, porous materials, especially those of a granular nature, tend not to fracture in a continuous manner, making analysis difficult. 2 Normative references This Technical Specification incorporates
31、by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text, and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this Technical S
32、pecification only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). EN ISO/IEC 17025General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:1999). 3 Terms a
33、nd definitions For the purposes of this Technical Specification, the following terms and definitions apply. 3.1 General terms 3.1.1 crack distinct microstructural discontinuity arising during or after manufacture caused by the action of thermal and/or mechanical stress and leading to the generation
34、of new surfaces which do not completely separate 3.1.2 flaw inhomogeneity which, through stress concentration, can act as a strength defining feature NOTE The term flaw used in this sense does not imply that the component is defective. 3.1.3 fracture process of propagation of a crack through a test-
35、piece or component 3.1.4 fracture origin source from which failure commences Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 06:04:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI CEN/TS 843-6:2004 (E) 5 3.2 Terms classifying inherently volume-distributed fracture
36、origins 3.2.1 agglomerate unintentional microstructural inhomogeneity usually of altered density, for example a cluster of grains of abnormal size, particles, platelets or whiskers, resulting from non-uniformity in processing 3.2.2 compositional inhomogeneity local variations in chemical composition
37、, usually manifest as agglomerates (3.2.1), or as areas denuded of or enriched in dispersed phases, or as changes in grain size 3.2.3 delamination generally planar crack within a material arising from the method of manufacture 3.2.4 inclusion discrete inhomogeneity, usually as a result of inorganic
38、contamination by a foreign body not removed during firing 3.2.5 large grain grain which is of abnormally large size as a result of poor particle size control or accelerated grain growth, and which can act as a flaw (3.1.2) 3.2.6 pore cavity or void within a material, which may be isolated or continu
39、ously interconnected with others 3.2.7 porous region zone of enhanced porosity, usually three-dimensional in nature and resulting from inhomogeneity or organic contamination in processing 3.2.8 porous seam zone of enhanced porosity, usually linear or planar in nature and resulting from inhomogeneity
40、 or organic contamination in processing 3.3 Terms classifying inherently surface-distributed fracture origins 3.3.1 chip small flake of material removed from a surface or an edge of an item or its fracture surface 3.3.2 handling damage scratches, chips or other damage resulting from contact between
41、items, test-pieces or fracture surfaces, not present normally 3.3.3 machining damage result of removal of small chips (see 3.3.1) or the formation of scratches at, or cracks near, the surface resulting from abrasive removal of material Licensed Copy: London South Bank University, London South Bank U
42、niversity, Tue Dec 12 06:04:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI CEN/TS 843-6:2004 (E) 6 3.3.4 open pore void connected to the external surface, usually by virtue of machining 3.3.5 pit surface depression or surface connected shallow pore, usually resulting from manufacturing conditions or
43、interaction with the external environment 3.4 Terms classifying features on fracture surfaces 3.4.1 fracture lines ridges or troughs running approximately parallel to the direction of propagation of a crack front, usually in the hackle (3.4.2) region NOTE In some cases, particularly with materials w
44、ith low fracture toughness, additional lines can be found on fracture surfaces resulting from interactions of the crack with free surfaces or other features, including so- called Wallner lines, arrest lines, wake hackle, etc. Definitions of such terms can be found in ASTM C1256 (see reference 1 in t
45、he Bibliography). 3.4.2 hackle region of rough fracture outside the mirror (3.4.3) and mist (3.4.4) regions, often with ridges or troughs emanating radially from the fracture origin (3.1.4) 3.4.3 mirror area of a fracture surface, usually approximately circular (or semicircular for near-edge fractur
46、e origins) and immediately surrounding a fracture origin (3.1.4), which is relatively flat and featureless compared with regions further removed from the fracture origin NOTENot all materials or fractures show obvious fracture mirrors. They tend to be visible most clearly in high-stress, acceleratin
47、g fractures from small flaws. 3.4.4 mist halo around the outer region of the mirror (3.4.3) where the roughness is enhanced with a texture elongated in the direction of fracture NOTEThe mist region is most clearly seen in glasses, glass-ceramics or ceramics with very fine grain sizes which produce s
48、mooth surfaces on fracture. 4 Significance and use Fractography is recommended as a routine diagnostic aid to the interpretation of fracture tests on test- pieces or of failures in components. Observation of the macroscopic features of fragments, such as cracks and their relative disposition, chips
49、and scratches, provides information about the likely directions of stressing. Observation of intermediate scale features on the fracture surface, such as the shape of hackle (3.4.2) and fracture lines (3.4.1) give indications of the approximate position of the fracture origin (3.1.4). Microscopic observations give information on the nature of the fracture origin, and thus may provide evidence of the reasons for fracture. The accumulation of additional information about the conditions of frac