ISO-14705-2008.pdf

Reference number ISO 14705:2008(E) © ISO 2008 INTERNATIONAL STANDARD ISO 14705 Second edition 2008-02-01 Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for hardness of monolithic ceramics at room temperature Céramiques techniques Méthode d'essai de dureté des céramiques monolithiques à température ambiante Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 02/16/2008 03:46:24 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 14705:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT © ISO 2008 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii © ISO 2008 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 02/16/2008 03:46:24 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 14705:2008(E) © ISO 2008 All rights reserved iii Contents Page Foreword iv 1 Scope 1 2 Normative references1 3 Terms and definitions .1 4 Vickers hardness.2 4.1 Principle2 4.2 Symbols, abbreviations and designations2 4.3 Significance and use.4 4.4 Apparatus .5 4.5 Test pieces .5 4.6 Procedure .5 4.7 Test report7 5 Knoop hardness.10 5.1 Principle10 5.2 Symbols and designations.10 5.3 Significance and use.12 5.4 Apparatus .12 5.5 Test pieces .13 5.6 Procedure .13 5.7 Test report14 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 02/16/2008 03:46:24 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 14705:2008(E) iv © ISO 2008 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 14705 was prepared by Technical Committee ISO/TC 206, Fine ceramics. This second edition cancels and replaces the first edition (ISO 14705:2000), which has been technically revised. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 02/16/2008 03:46:24 MSTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 14705:2008(E) © ISO 2008 All rights reserved 1 Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for hardness of monolithic ceramics at room temperature 1 Scope This International Standard specifies a test method for determining the Vickers and Knoop hardness of monolithic fine ceramics at room temperature. 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. ISO 4545-1:2005, Metallic materials Knoop hardness test Part 1: Test method ISO 4545-2:2005, Metallic materials Knoop hardness test Part 2: Verification and calibration of testing machines ISO 4545-3:2005, Metallic materials Knoop hardness test Part 3: Calibration of reference blocks ISO 4545-4:2005, Metallic materials Knoop hardness test Part 4: Table of hardness values ISO 6507-1:2005, Metallic materials Vickers hardness test Part 1: Test method ISO 6507-2:2005, Metallic materials Vickers hardness test Part 2: Verification and calibration of testing machines ISO 6507-3:2005, Metallic materials Vickers hardness test Part 3: Calibration of reference blocks ISO 6507-4:2005, Metallic materials Vickers hardness test Part 4: Tables of hardness values 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 Vickers hardness value obtained by dividing the applied force by the surface area of the indentation computed from the mean of the measured diagonals of the indentations, assuming that the indentation is an imprint of the undeformed indenter NOTE 1 Vickers hardness may be expressed in two different units: a) with units of GPa, obtained by dividing the applied force, in kN, by the surface area of the indentation, in mm2; b) Vickers hardness number, obtained by dividing the applied force, in kgf, by the surface area of the indentation, in mm2, without the units specified. NOTE 2 Use of Vickers hardness with units of GPa is preferred. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 02/16/2008 03:46:24 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 14705:2008(E) 2 © ISO 2008 All rights reserved 3.2 Vickers indenter indenter in the shape of a right-angle pyramid with a square base and an angle between opposite faces of 136° See Table 1 and Figure 1. 3.3 Knoop hardness value obtained by dividing the applied force by the projected area of the indentation computed from the measurement of the long diagonal of the indentation, assuming that the indentation is an imprint of the undeformed indenter NOTE 1 Knoop hardness may be expressed in two different units: a) with units of GPa, obtained by dividing the applied force, in kN, by the projected area of the indentation, in mm2; b) Knoop hardness number, obtained by dividing the applied force, in kgf, by the projected area of the indentation, in mm2, without units specified. NOTE 2 The use of Knoop hardness with units of GPa is preferred. 3.4 Knoop indenter indenter in the shape of a rhombic-based pyramid with the two angles between the opposite edges at 172,5° and 130° See Table 3 and Figure 6. 4 Vickers hardness 4.1 Principle Forcing a diamond indenter in the form of a right-angle pyramid with a square base, and with a specified angle between opposite faces at the vertex into the surface of a test piece and measuring the length of the diagonals of the indentation left in the surface after removal of the test force, F. See Figures 1 and 2. 4.2 Symbols, abbreviations and designations 4.2.1 See Table 1 and Figures 1 and 2. 4.2.2 The Vickers hardness is denoted by the symbol HV preceded by the hardness value and followed by a number representing the test force (see Table 2). EXAMPLES a) Use of the SI unit (GPa). 15,0 GPa HV 9,807 N represents a Vickers hardness of 15,0 GPa, determined with a test force of 9,807 N (1 kgf). b) Use of the Vickers hardness number (no units specified). 1 500 HV 1 represents a Vickers hardness number of 1 500, determined with a test force of 9,807 N (1 kgf). Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 02/16/2008 03:46:24 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 14705:2008(E) © ISO 2008 All rights reserved 3 Table 1 Symbols, abbreviations and designations for Vickers hardness testing Symbol or abbreviation Designation Angle between the opposite faces at the vertex of the pyramidal indenter (136° ± 0,5°) F Test force, in newtons d Arithmetic mean, in millimetres, of the two diagonals d1 and d2 HV Vickers hardness Test force Constant Surface area of indentation =× (1) units of GPa (preferred) 22 136 2sin 2 0,0010,001854 F F dd ° = (2) hardness number (no units specified) 22 136 2sin 2 0,1020,1891 F F dd ° = c Arithmetic mean of the half of the two median crack lengths 2c1 and 2c2 S.D. Standard deviation () 2 HVHV 1 n n = where HV is the arithmetic mean of the Vickers hardness HVn n = HVn is the HV obtained from nth indentation n is the number of indentations NOTE 11 Constant0,102 9,807g = where g is the acceleration due to gravity. Table 2 Hardness symbols and the nominal values of test forces, F, for Vickers hardness testing Hardness symbol Test force, F (nominal value) HV 4,903 N or HV 0,5 HV 9,807 N or HV 1 HV 19,61 N or HV 2 HV 29,42 N or HV 3 HV 49,03 N or HV 5 HV 98,07 N or HV 10 HV 196,1 N or HV 20 4,903 N 9,807 N 19,61 N 29,42 N 49,03 N 98,07 N 196,1 N Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 02/16/2008 03:46:24 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 14705:2008(E) 4 © ISO 2008 All rights reserved Figure 1 Vickers indenter (diamond pyramid) Figure 2 Vickers indentation 4.3 Significance and use Vickers indentation diagonal lengths are approximately 2,8 times shorter than the long diagonal of Knoop indentations, and the indentation depth is approximately 1,5 times deeper than Knoop indentations made at the same force. Vickers indentations are influenced less by the specimen surface flatness, parallelism of the diamond axis to the test piece surface normal, and surface finish than Knoop indentations, but these parameters should be considered nonetheless. Vickers indentations are much more likely to cause cracks in fine ceramics than are Knoop indentations. Conversion between hardness scales shall not be made. Vickers indentations on metallic materials are mainly formed by the plastic deformation. However, Vickers indentations on fine ceramics are formed by micro-cracking and micro-fracture, besides plastic deformation. This difference shall be noted for comparing the hardnesses of metals and ceramics. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 02/16/2008 03:46:24 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 14705:2008(E) © ISO 2008 All rights reserved 5 4.4 Apparatus 4.4.1 Testing machine, capable of applying a predetermined test force in the range of 4,903 N (0,5 kgf) to 98,07 N (10 kgf), preferably 9,807 N (1 kgf), in accordance with ISO 6507-2. Verification of the test force shall be carried out in accordance with ISO 6507-2. 4.4.2 Diamond indenter, in the shape of a right-angle pyramid with a square base, as specified in ISO 6507-1 and ISO 6507-2. Verification of the indenter shall be carried out in accordance with ISO 6507-2. 4.4.3 Measuring device, capable of measuring the indentation diagonals with a readout resolution of ± 0,2 µm or finer. A numerical aperture (NA) of between 0,60 and 0,95 for the objective lens for the microscope is recommended. Verification of the measuring device shall be carried out in accordance with ISO 6507-2. NOTE Indirect verification can be carried out by means of standardized blocks calibrated in accordance with ISO 6507-3, following ISO 6507-2, or other approved and traceable ceramic standard reference blocks. 4.5 Test pieces 4.5.1 The test shall be carried out on a surface which is smooth, flat and free from foreign matter. The test piece shall be polished to permit accurate measurement of the diagonal lengths of the indentation. Preparation shall be carried out in such a way that any alteration of the surface hardness is minimized. 4.5.2 The thickness of the test piece shall be at least 0,5 mm. It shall be at least 1,5 times the diagonal of the indentation, d, and at least 2 times the crack length, c, whichever is greater. No indentation damage shall be visible at the back of the test piece on completion of the test. 4.6 Procedure 4.6.1 In general, the test shall be carried out at room temperature within the limits of 10 °C to 35 °C. Tests carried out under controlled conditions shall be made at a temperature of 23 °C ± 5 °C. 4.6.2 The recommended test force is 9,807 N (1 kgf). In cases where significant chipping or lateral crack- spalling occurs or where the impression is too faint, the test forces within the range 4,903 N (0,5 kgf) to 196,1 N (20 kgf), listed in Table 2, may be used. Other instances where a heavier load may be required are where the grain structure is very coarse and the indentation area at lower loads may contact only a few grains of the material (e.g. a multiphase