CEN/TS 843-6:2004

SLOVENSKI STANDARD
01-september-2004
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Advanced technical ceramics - Monolithic ceramics. Mechanical properties at room
temperature - Part 6: Guidance for fractographic investigation
Hochleistungskeramik - Monolithische Keramik - Mechanische Eigenschaften bei
Raumtemperatur - Teil 6: Leitlinie für die fraktographische Untersuchung
Céramiques techniques avancées - Céramiques monolithiques -Propriétés mécaniques
a température ambiante - Partie 6: Guide pour l'analyse fractographique
Ta slovenski standard je istoveten z: CEN/TS 843-6:2004
ICS:
81.060.30 Sodobna keramika Advanced ceramics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CEN/TS 843-6
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
June 2004
ICS 81.060.30
English version
Advanced technical ceramics - Monolithic ceramics. Mechanical
properties at room temperature - Part 6: Guidance for
fractographic investigation
Céramiques techniques avancées - Céramiques Hochleistungskeramik - Monolithische Keramik -
monolithiques -Propriétés mécaniques à température Mechanische Eigenschaften bei Raumtemperatur - Teil 6:
ambiante - Partie 6: Guide pour l'analyse fractographique Leitlinie für die fraktographische Untersuchung
This Technical Specification (CEN/TS) was approved by 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.
CEN 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 about 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, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 843-6:2004: E
worldwide for CEN national Members.

Contents Page
Foreword . 3
1 Scope. 4
2 Normative references. 4
3 Terms and definitions. 4
3.1 General terms . 4
3.2 Terms classifying inherently volume-distributed fracture origins . 5
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 Apparatus. 7
5.1 Preparation and cleaning facilities. 7
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 . 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 general 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.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-forma. 42
Bibliography . 44
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 mandate 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 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 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 Technical 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
1 Scope
This Technical Specification contains guidelines to be adopted when evaluating 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 technical 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 difficult.
2 Normative references
This Technical Specification incorporates 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 Specification 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 17025 General requirements for the competence of testing and calibration laboratories
(ISO/IEC 17025:1999).
3 Terms and 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 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-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 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, 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 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 continuously 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 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 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
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
interaction with the external environment
3.4 Terms classifying features on
...