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1、INTERNATIONAL STANDARD ISO 17565 First edition 2003-12-15 Reference number ISO 17565:2003(E) ISO 2003 Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for flexural strength of monolithic ceramics at elevated temperature Cramiques techniques Mthode dessai de rsistance la fle
2、xion des cramiques monolithiques temprature leve Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:45:57 MDTNo reproduction or networking permitted without license from IHS -,-,
3、- ISO 17565:2003(E) ii ISO 2003 All rights reserved PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes 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 compute
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6、ntral Secretariat at the address given below. ISO 2003 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
7、 at the address below or ISOs 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 Copyright International Organization for Standardization Pro
8、vided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:45:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 17565:2003(E) ISO 2003 All rights reserved iii Contents Page 1Scope 1 2Normative references 1 3Terms an
9、d definitions 1 4Principle 3 5Apparatus . 3 5.1Testing machine 3 5.2Heating device . 3 5.3Temperature measuring and indicating instruments . 4 5.4Testing fixture 5 5.5Micrometer . 9 6Test pieces . 9 6.1Test piece size . 9 6.2Test piece preparation 10 7Procedure . 10 8Calculation . 13 8.1Standard for
10、mula for the flexural strength in four-point flexure . 13 8.2Standard formula for the flexural strength in three-point flexure . 14 8.3Corrections for chamfer size 14 8.4Corrections for thermal expansion 14 8.5Mean strength and standard deviation 15 9Accuracy and precision 15 10Test report 15 11Stre
11、ngth scaling factors 16 Annex A (informative) General information . 17 Annex B (normative) Chamfer correction factors . 18 Annex C (normative) Corrections for thermal expansion . 21 Annex D (informative) Weibull scaling factors . 23 Annex E (informative) VAMAS round robin 25 Bibliography . 26 Copyri
12、ght International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:45:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 17565:2003(E) iv ISO 2003 All rights reserved For
13、eword 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 tech
14、nical 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
15、 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 t
16、o 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
17、 identifying any or all such patent rights. ISO 17565 was prepared by Technical Committee ISO/TC 206, Fine ceramics. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:45:57 MDTN
18、o reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARDISO 17565:2003(E) ISO 2003 All rights reserved 1 Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for flexural strength of monolithic ceramics at elevated temperature 1Scope This Int
19、ernational Standard describes the method of test for determining the flexural strength of monolithic fine ceramics and whisker- or particulate-reinforced ceramic composites at elevated temperature. Flexural strength is one measure of the uniaxial strength of fine ceramics. This test method may be us
20、ed for materials development, quality control, characterization and design data generation purposes. 2Normative 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 late
21、st edition of the referenced document (including any amendments) applies. ISO 3611:1978, Micrometer callipers for external measurement ISO 7500-1:1), Metallic materials Verification of static uniaxial testing machines Part 1: Tension/compression testing machines Verification and calibration of the f
22、orce-measuring system ISO 14704:2000, Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for flexural strength of monolithic ceramics at room temperature IEC 60584-1:1995, Thermocouples Part 1: Reference tables 3Terms and definitions For the purposes of this document, the fol
23、lowing terms and definitions apply. 3.1 flexural strength maximum nominal stress at fracture of a specified elastic beam loaded in bending 3.2 four-point flexure configuration of flexural strength testing where a test piece is equally loaded by two bearings symmetrically located between two support
24、bearings See Figure 1. NOTEThe bearings may be cylindrical rollers or cylindrical bearings. 1)To be published. (Revision of ISO 7500-1:1999) Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale,
25、04/12/2007 22:45:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 17565:2003(E) 2 ISO 2003 All rights reserved 3.3 four-point-1/4 point flexure specific configuration of four-point flexural strength testing where the inner bearings are situated one quarter of the supp
26、ort span away from the two outer bearings See Figure 1 a). a)Four-point-1/4 point flexure b)Four-point-1/3 point flexure c)Three-point flexure Key 1loading bearings 2support bearing Figure 1 Flexural test configurations Copyright International Organization for Standardization Provided by IHS under l
27、icense with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:45:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 17565:2003(E) ISO 2003 All rights reserved 3 3.4 four-point-1/3 point flexure specific configuration of four-point flexural
28、 strength testing where the inner bearings are situated one third of the support span away from the two outer bearings See Figure 1 b). 3.5 three-point flexure configuration of flexural strength testing where a test piece is loaded at a location midway between two outer bearings See Figure 1 c). NOT
29、EFour-point flexure is usually preferred since a larger amount of material is exposed to the maximum stress. See Bibliography for more information. 4Principle A beam test piece with a rectangular cross section is loaded in flexure until fracture. The load at fracture, the test fixture and test piece
30、 dimensions are used to compute the flexural strength, which is a measure of the uniaxial tensile strength of a ceramic. The material is assumed to be isotropic and linearly-elastic. Testing is performed at elevated temperature in air or inert atmosphere. Load is monitored versus displacement or tim
31、e in order to confirm that the beam test piece fractured under elastic conditions. This International Standard is an elevated-temperature adaptation of ISO 14704. See Annex A for additional information on this test method. 5Apparatus 5.1Testing machine A suitable testing machine capable of applying
32、a uniform crosshead speed shall be used. The testing machine shall be in accordance with ISO 7500-1: Class 1 with an accuracy of of indicated load at fracture. 5.2Heating device 5.2.1General The furnace shall be capable of heating the test fixture and test piece as well as maintaining a uniform and
33、constant temperature during the strength test. The furnace may have an air, inert gas or vacuum environment, as required. If an inert gas or vacuum chamber is used, and it is necessary to transmit the load through a seal, bellows or a fitting, it shall be verified that load losses or errors are less
34、 than of the expected fracture loads. The furnace may be designed so that test pieces are loaded into either hot or cold furnaces. 5.2.2Test piece temperature stability The furnace shall be controlled by a device for maintaining a constant temperature within or better within the working space of the
35、 furnace, during the time that the test piece is loaded to fracture. 5.2.3Test piece temperature uniformity The furnace shall be capable of maintaining the test piece temperature uniform. It shall previously be determined that the temperature of the test piece shall not vary more than over its lengt
36、h after a hold time at the required test temperature. 1 % 1 % 2 C 10 C 15 min Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:45:57 MDTNo reproduction or networking permitted
37、without license from IHS -,-,- ISO 17565:2003(E) 4 ISO 2003 All rights reserved 5.2.4Furnace heating rate The furnace control device shall also be capable of controlling the heating rates of the furnace and preventing temperature overshoots. 5.2.5Furnace stability The time for the system to reach th
38、ermal equilibrium at test temperature shall be determined for the test temperature to be used. 5.3Temperature measuring and indicating instruments 5.3.1General Thermocouple temperature measuring equipment shall have a resolution of at least and an accuracy of or better. Optical pyrometers, if used,
39、shall have a resolution of at least and an accuracy of or better. NOTE 1Resolution should not be confused with accuracy. Beware of instruments that have a resolution (read out) of , but have an accuracy of only ; e.g., an instrument with a accuracy would only be accurate to at . NOTE 2Thermocouple t
40、emperature measuring instruments typically approximate the temperature-electromotive force (EMF) tables, but with a few degrees error. 5.3.2Thermocouples Thermocouples in accordance with IEC 60584-1 shall be used. The thermocouples shall exhibit low thermal inertia (the diameter of the wires shall n
41、ot be greater than ). The thermocouples shall have a sufficient length within the furnace (with respect to heat conduction along the wires). The measuring thermocouple tip shall be as close as possible to or contacting the test piece. NOTE 1In some furnaces, a control thermocouple may be installed a
42、t a location within the furnace which is convenient for furnace control and a second measuring thermocouple may be in close proximity to the test piece. NOTE 2The thermocouple should not contact the test piece if there is a chance the test piece will be misaligned. NOTE 3The thermocouple should not
43、contact the test piece if it will chemically react with the test piece. 5.3.3Verification of the thermocouple temperature measuring system Thermocouples shall be checked periodically since calibration may drift with usage or contamination. 5.3.4Radiation pyrometers Radiation pyrometers (thermometers
44、) may be used in instances wherein suitable thermocouples are not available, particularly at temperatures above . Pyrometers may either be of the disappearing filament type or an automatic type. Pyrometers may either be spectral (operate over a narrow wavelength band), dual wavelength (operate over
45、two narrow wavelength bands) or total (integrate or average over all wavelengths). Radiation pyrometry requires special care in order to obtain accurate and precise results. Ensure that blackbody conditions are obtained, or correct the temperature for the actual emissivity of the test piece in its e
46、nvironment. The pyrometer should view the test piece at right angles to one of the four long surfaces. The target size (or viewed area) of the pyrometer shall be less than in diameter. Corrections for radiation absorption or reflectance may be necessary if the furnace has a window. The window shall
47、be sufficiently large such that the radiation emanating from the window completely fills the objective lens of the radiation thermometer, but the window should not be so large as to cause appreciable heat loss or thermal gradients in the furnace. NOTESee ASTM Standard Test Methods E 452, E 639, E 12
48、56, and BS 1041, part 5 for additional information. 1 C 5 C 5 C 5 C 1 C 10 C 1 %12 C 1 200 C 0,5 mm 1 600 C 3 mm Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/12/2007 22:45:57 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 17565:2003(E) ISO 2003 All rights reserved 5 5.4Testing fixture 5.4.1General Thre