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1、Reference number ISO 15490:2000(E) ISO 2000 INTERNATIONAL STANDARD ISO 15490 First edition 2000-07-01 Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for tensile strength of monolithic ceramics at room temperature Cramiques techniques Mthode dessai de rsistance la traction
2、 des cramiques monolithiques temprature ambiante Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:01:46 MDTNo reproduction or networking permitted without license from IHS -,-,
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6、 given below. ISO 2000 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 ISOs me
7、mber 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.ch Web www.iso.ch Printed in Switzerland ii ISO 2000 All rights reserved Copyright International Organization for Standardization Provi
8、ded by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:01:46 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15490:2000(E) ISO 2000 All rights reservediii ContentsPage Foreword.iv 1Scope 1 2Normative references1 3T
9、erms and definitions .1 4Principle2 5Apparatus.2 6Test specimen2 7Procedures.3 8Calculation5 9Report .5 Annex A (informative) Shape and dimensions of test specimen .7 Bibliography10 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technica
10、l Standards 1/9972545001 Not for Resale, 04/21/2007 02:01:46 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15490:2000(E) iv ISO 2000 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards b
11、odies (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 organizati
12、ons, 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
13、 ISO/IEC Directives, Part 3. 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 s
14、ome of the elements of this International Standard may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 15490 was prepared by Technical Committee ISO/TC 206, Fine ceramics. Annex A of this International Stand
15、ard is for information only. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:01:46 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STAN
16、DARDISO 15490:2000(E) ISO 2000 All rights reserved1 Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for tensile strength of monolithic ceramics at room temperature 1Scope This International Standard specifies the method of test for determining the tensile strength under un
17、iaxial loading of monolithic fine ceramics and whisker or particulate-reinforced ceramic composites at room temperature. This test method, in which parasitic bending is minimized, may be used for material development, material comparison, quality assurance, characterization and design data generatio
18、n. 2Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agre
19、ements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registe
20、rs of currently valid International Standards. ISO 3611:1978, Micrometer callipers for external measurement. ISO 7500-1:1999,MetallicmaterialsVerificationofstaticuniaxialtestingmachinesPart 1: Tension/compression testing machines Verification and calibration of the force-measuring sytem. 3Terms and
21、definitions For the purposes of this International Standard, the following terms and definitions apply. 3.1 tensile stress value of tensile load applied to a test specimen divided by the original sectional area of the gauge part of a test specimen 3.2 tensile strength maximum tensile stress applied
22、to a test specimen during a tensile strength test 3.3 maximum tensile load maximum load applied to a test specimen during a tensile strength test 3.4 gauge section parallel portion of the the test specimen having the same cross section as its middle part Copyright International Organization for Stan
23、dardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:01:46 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15490:2000(E) 2 ISO 2000 All rights reserved 3.5 gripped region end part of a test speci
24、men which is held by the gripping device of a tensile test machine 3.6 gripping device device to hold a test specimen and to transfer a load to a test specimen during a tensile test 3.7 bending strain component value of bending strain generated on the surface of the gauge part of a test specimen by
25、axial misalignment, divided by the average strain 3.8 percent bending bending strain component times 100 3.9 strain fractional increase in length when a test specimen is loaded in tension 3.10 breaking load load at which fracture occurs 4Principle The test consists of applying tensile force to a tes
26、t specimen by uniaxial loading until fracture, for the purpose of determining the tensile strength. 5Apparatus 5.1Tensile testing machine The testing machine used for tensile test shall conform to the requirements of ISO 7500-1:1999, Class 1. 5.2Gripping devices Every endeavour shall be made to ensu
27、re that test specimens are held in such a way that the force is applied as axially as possible (see 7.2). For this purpose, various types of the gripping devices may be used. 6Test specimen 6.1Shape and dimensions The shape and dimensions of the test specimens depend on several factors, including th
28、e purpose of the tensile test itself, the gripping devices and the shape and dimensions of the ceramic products whose tensile strength is to be determined. Therefore, various shapes and dimensions may be used. The shapes and dimensions, however, shall be determined so that the tensile stress is appl
29、ied uniformly in the gauge section (see 7.2). Also, it shall be ensured that stress concentrations which could lead to undesired fractures outside the gauge section are minimized. In addition, the cross section of the gauge section shall be uniform with a dimensional accuracy greater than ? 0,5 %. T
30、he test specimens that have been applied to testing fine ceramics are shown in annex A. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:01:46 MDTNo reproduction or networking
31、permitted without license from IHS -,-,- ISO 15490:2000(E) ISO 2000 All rights reserved3 6.2Test specimen preparation Surface finishes in the gauge section of the order of average roughness, Ra 0,2 ?m to 0,4 ?m (measured in the longitudinal direction) are recommended in order to avoid surface roughn
32、ess-related fracture. Unless it is part of an exercise to determine the effects of grinding methods, it is highly recommended that the final grinding operation in the gauge section be performed along the longitudinal direction of the test specimen in order to ensure that grinding marks are parallel
33、to the applied tensile stress. Care shall be taken in storage and handling of finished test specimens to avoid the introduction of random and severe flaws. NOTEIn some cases the final surface finish may not be as important as the subsurface damage produced during the grinding process. This damage is
34、 not readily observed or measured. 6.3Number of test specimens As a general rule, a minimum of ten tests is required for the purpose of estimating a mean, and thirty or more tests are needed to estimate the strength distribution parameters such as Weibull modulus and characteristic strength. Tests w
35、ith fractures outside the gauge section shall not be included in the calculation of mean or standard deviation, but may be included in the calculation of Weibull statistics as censored tests. NOTEThe number of test specimens needed for the test depends on the precision required for estimating the pa
36、rameters of strength properties. 7Procedures 7.1Test specimen dimensions The diameter or thickness and width of the gauge section of each test specimen shall be determined to within 0,02 mm. Measurements on at least three different cross sections in the gauge section shall be made. The average of th
37、e multiple measurements shall be used in calculating the cross sectional area. 7.2Axial alignment The testing system shall be verified using the following procedures. Three or four strain gauges are equally spaced around the circumferences on two cross-sectional planes. The strain gauge planes shall
38、 be symmetrically located about the longitudinal midpoint of the gauge section, and shall be separated by at least of the length of the gauge section. When the gauge section is not long enough to have two strain gauge planes, one plane may be used. In this case, the location shall be the longitudina
39、l midpoint of the gauge section. When axial strain gauges are mounted, the gauge axis shall be aligned with the stress axis so that the deviation is less than 0,035 rad (2o). Ideally the verification shall be made for all the individual test specimens to be tested. However, if this is not possible o
40、r desired, a permanent strain-gauged “dummy” test specimen may be used, provided that the test specimen to be tested has exactly the same shape as the “dummy” one. It is most preferable that it be of the same material as that to be tested. Copyright International Organization for Standardization Pro
41、vided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:01:46 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15490:2000(E) 4 ISO 2000 All rights reserved Mount the test specimen in the gripping device and apply a
42、 load so as to give an average strain of one half of that expected at fracture. Measure the amount of strain as a function of average strain, and calculate percent bending using the following equation: B ? ? ? ?2100 13 2 24 2 1 2 1234 ( _ )( _ ) / ? ? for four gauges and 2221/2 1232 32 33 1 123 _ ()
43、 2100B ? ? ? ? ? ? ? ? for three gauges, where Bis the percentage bending; ? 1234 ,andare strain readings for strain gauges. When alignment is verified for the individual test specimens, percentage bending shall not exceed 7,5 % at an average strain of one half that expected at fracture. Alignment w
44、ith the percentage bending of 5 % or less is required when the testing system is verified using a permanent strain-gauged “dummy” test specimen, since this will minimize the contribution of the testing system to percentage bending in the actual test specimens. This verification shall be made at leas
45、t at the beginning and end of each test series. Verification is highly recommended for all the test specimens. Care shall be taken to avoid placing the strain gauges too near geometric transitions in the gauge section which can cause strain concentration and inaccurate measurements of the strain in
46、the uniform gauge section. 7.3Test mode and rates Various test modes including load, displacement (of the test machine cross-head) and strain control may be used. Sufficiently rapid testing rates are recommended so that final fracture is reached in less than 10 s using one half the breaking load in
47、order to minimize environmental effects and thus obtain the intrinsic value of ultimate tensile strength. In case of evaluating rate effects, lower rates can be used. In all cases the test mode and rate shall be reported. NOTEThe most common test mode is displacement control. In this case, cross-hea
48、d speeds greater than 0,008 33 mm/s (0,5 mm/min) are recommended. For load control, stress rates greater than 20 MPa/s are recommended. Generally, these conditions satisfy the above requirements, if the testing assembly is sufficiently rigid during the last half of the duration of the test. 7.4Recording After conducting the test, the breaking load shall be read to an accuracy of 1,0 % and noted for the report, and the fracture location shall be identified. If required, examine the fracture surface with a micr