DIN EN 843-6-2009 Advanced technical ceramics - Mechanical properties of monolithic ceramics at room temperature - Part 6 Guidance for fractographic investigation English version o.pdf

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1、December 2009DEUTSCHE NORM English price group 18No 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!$ZR“1559647

2、www.din.deDDIN EN 843-6Advanced technical ceramics Mechanical properties of monolithic ceramics at room temperature Part 6: Guidance for fractographic investigationEnglish version of DIN EN 843-6:2009-12Hochleistungskeramik Mechanische Eigenschaften monolithischer Keramik bei Raumtemperatur Teil 6:

3、Leitlinie fr die fraktographische UntersuchungEnglische Fassung DIN EN 843-6:2009-12SupersedesDIN CEN/TS 843-6:2004-08www.beuth.deDocument comprises pages46DIN EN 843-6:2009-12 National foreword This standard has been prepared by Technical Committee CEN/TC 184 “Advanced technical ceramics” (Secretar

4、iat: BSI, United Kingdom). The responsible German body involved in its preparation was the Normenausschuss Materialprfung (Materials Testing Standards Committee), Technical Committee NA 062-02-91 AA Prfung von Hochleistungskeramik Monolithische Werkstoffe. Amendments This standard differs from DIN C

5、EN/TS 843-6:2004-08 as follows: a) The standard is published as a European standard. b) The standard has been editorially revised. Previous editions DIN CEN/TS 843-6: 2004-08 2 EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 843-6August 2009ICS 81.060.30 Supersedes CEN/TS 843-6:2004 English Versio

6、nAdvanced technical ceramics - Mechanical properties ofmonolithic ceramics at room temperature - Part 6: Guidance forfractographic investigationCramiques techniques avances - Proprits mcaniquesdes cramiques monolithiques temprature ambiante -Partie 6: Guide pour lanalyse fractographiqueHochleistungs

7、keramik - Mechanische Eigenschaftenmonolithischer Keramik bei Raumtemperatur - Teil 6:Leitlinie fr die fraktographische UntersuchungThis European Standard was approved by CEN on 16 July 2009.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for

8、giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official ve

9、rsions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium,

10、 Bulgaria, 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 United Kingdom.EUROPEAN COMMITTEE FOR STANDA

11、RDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 843-6:2009: EContents Page Foreword . 3 1 Scope 4 2 Normat

12、ive references . 4 3 Terms and definitions . 4 3.1 General terms 4 3.2 Terms classifying inherently volume-distributed fracture origins 4 3.3 Terms classifying inherently surface-distributed fracture origins 5 3.4 Terms classifying features on fracture surfaces . 6 4 Significance and use 6 5 Apparat

13、us 6 5.1 Preparation and cleaning facilities 6 5.2 Observational facilities . 7 6 Recommended procedure 9 6.1 Outline 9 6.2 Specimen storage and cleaning of fracture surfaces . 9 6.3 Visual inspection . 9 6.4 Optical microscope examination . 10 6.5 Identification of major fracture surface features .

14、 10 6.6 Scanning electron microscope examination . 12 6.7 Identification of fracture origin 12 6.8 Identification of chemical inhomogeneity at fracture origin 13 6.9 Drawing conclusions 13 7 Report . 13 Annex A (informative) Crack patterns in ceramic bodies . 14 Annex B (informative) Examples of gen

15、eral features of fracture surfaces 17 Annex C (informative) Examples of procedure for fracture origin identification. 19 C.1 Single large pores . 20 C.2 Agglomerates 22 C.3 Large grains . 24 C.4 Compositional inhomogeneities . 26 C.5 Delaminations 28 C.6 Handling damage 30 C.7 Machining damage 31 C.

16、8 Oxidation pitting 33 C.9 Complex origins 35 C.10 No obvious origins 36 Annex D (informative) Use of fracture mechanical information to aid fractography. 37 D.1 Fracture stress and origin size 37 D.2 Fracture stress and fracture mirror size . 40 Annex E (informative) Example layout of reporting pro

17、-forma . 42 Bibliography . 44 EN 843-6:2009 (E) DIN EN 843-6:2009-12 2Foreword This document (EN 843-6:2009) has been prepared by Technical Committee CEN/TC 184 “Advanced technical ceramics”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national stan

18、dard, either by publication of an identical text or by endorsement, at the latest by February 2010, and conflicting national standards shall be withdrawn at the latest by February 2010. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent righ

19、ts. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes CEN/TS 843-6:2004. EN 843 Advanced technical ceramics Mechanical properties of monolithic ceramics at room temperature consists of six parts: Part 1: Determination of flexural

20、 strength Part 2: Determination of Youngs modulus, shear modulus and Poissons ratio Part 3: Determination of subcritical 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

21、 for fractographic investigation According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, H

22、ungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN 843-6:2009 (E) DIN EN 843-6:2009-12 31 Scope This Part of EN 843 contains guidelines to be adopted when eva

23、luating the appearance of the fracture surface of an advanced technical 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 technica

24、l ceramics are amenable to fractography. In particular, coarse-grained 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 diffic

25、ult. 2 Normative references The following referenced documents are indispensable for the 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 ISO/IEC 17025, Gen

26、eral requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:2005) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 General terms 3.1.1 crack distinct microstructural discontinuity arising during or after manufac

27、ture caused by the action of thermal and/or mechanical stress and leading to the generation 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

28、the component is defective. 3.1.3 fracture process of propagation of a crack through a test-piece or component 3.1.4 fracture origin source from which failure commences 3.2 Terms classifying inherently volume-distributed fracture origins 3.2.1 agglomerate unintentional microstructural inhomogeneity

29、usually of altered density, for example a cluster of grains of abnormal size, particles, platelets or whiskers, resulting from non-uniformity in processing EN 843-6:2009 (E) DIN EN 843-6:2009-12 43.2.2 compositional inhomogeneity local variations in chemical composition, usually manifest as agglomer

30、ates (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 contamination by a foreign bod

31、y 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 continuously interconnected with othe

32、rs 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 or organic contamination in p

33、rocessing 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 items, test-pieces or fracture

34、 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 3.3.4 open pore void connected to the external surface, usually by virtue of machining 3.3.5 p

35、it surface depression or surface connected shallow pore, usually resulting from manufacturing conditions or interaction with the external environment EN 843-6:2009 (E) DIN EN 843-6:2009-12 53.4 Terms classifying features on fracture surfaces 3.4.1 fracture lines ridges or troughs running approximate

36、ly 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 with low fracture toughness, additional lines can be found on fracture surfaces resulting from interactions of the crack with free surfaces or other feat

37、ures, including so-called Wallner lines, arrest lines, wake hackle, etc. Definitions of such terms can be found in ASTM C1256 (see reference 1 in the 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 radia

38、lly from the fracture origin (3.1.4) 3.4.3 mirror area of a fracture surface, usually approximately circular (or semicircular for near-edge fracture origins) and immediately surrounding a fracture origin (3.1.4), which is relatively flat and featureless compared with regions further removed from the

39、 fracture origin NOTE Not all materials or fractures show obvious fracture mirrors. They tend to be visible most clearly in high-stress, accelerating 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

40、the direction of fracture NOTE The mist region is most clearly seen in glasses, glass-ceramics or ceramics with very fine grain sizes which produce smooth surfaces on fracture. 4 Significance and use Fractography is recommended as a routine diagnostic aid to the interpretation of fracture tests on t

41、est-pieces or of failures in components. Observation of the macroscopic features of fragments, such as cracks and their relative disposition, chips and scratches, provides information about the likely directions of stressing. Observation of intermediate scale features on the fracture surface, such a

42、s 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 additio

43、nal information about the conditions of fracture (stresses, forces, temperature, time under stress, likelihood of impact, etc.) is highly desirable for achieving justifiable conclusions. 5 Apparatus 5.1 Preparation and cleaning facilities 5.1.1 Cutting wheel, for large specimens. A diamond-bladed sa

44、w. NOTE This is needed to cut small samples for microscope observation, particularly in the scanning electron microscope EN 843-6:2009 (E) DIN EN 843-6:2009-12 65.1.2 Ultrasonic bath, for cleaning the fracture surface. 5.1.3 Compressed air supply, for drying specimens after cleaning and for removal

45、of dust or lint. The supply should be dry and oil-free. 5.2 Observational facilities 5.2.1 Small hand lens, with a magnification in the range 3 to 8 times. 5.2.2 Optical microscope, preferably with photomicrographic facilities, and with variable magnification in the range 5 to 50 times. NOTE As an a

46、lternative to photomicrographic facilities, a camera with appropriate lenses and a macrophotography stand. 5.2.3 Illumination system, a light source that can be positioned to the side of the test-piece to provide contrast on the fracture surface. 5.2.4 Scanning electron microscope (SEM), preferably

47、with energy-dispersive X-ray (EDX) analysis equipment fitted. EN 843-6:2009 (E) DIN EN 843-6:2009-12 7Location of originCollection and cleanfragmentsHistory of fractureObjection Acton: Deduction: Result:Visual inspectionPrimary fracturefaceBinocular macroscopeinspectionIdentify features and locate o

48、riginTentativeclassification oforiginMore ?Mechanicalnature of originSEM inspection.Origin size, fracturemechanicsMechanicalcircumstancesof fractureMore ?Chemicalnature of originReportOverallconclusionsChemical causes of failure EDX analysis.Origin chemicalinhomogeneityNoNoYesYesFigure 1 Flow chart

49、for general fractographic procedure EN 843-6:2009 (E) DIN EN 843-6:2009-12 86 Recommended procedure 6.1 Outline The sequence of steps in undertaking fractography on a specimen is outlined in Figure 1. It should be noted that not all the steps will be necessary on every occasion; for example, if only a check on approximate position of failure is needed, SEM examination is not generally necessary. Thus, the following series of paragraphs should be used as appropriate to the task, defined by the type of investigation needed. 6.2 Specimen sto