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1、BRITISH STANDARD BS ISO 15490:2008 Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for tensile strength of monolithic ceramics at room temperature ICS 81.060.30 ? Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Bo
2、eing Co/5910770001 Not for Resale, 08/14/2008 22:17:14 MDTNo reproduction or networking permitted without license from IHS -,-,- BS ISO 15490:2008 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2008 BSI 2008 ISBN 978 0 580 62549 7 N
3、ational foreword This British Standard is the UK implementation of ISO 15490:2008. It supersedes BS ISO 15490:2000 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee RPI/13, Advanced technical ceramics. A list of organizations represented on this committ
4、ee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments/corrigenda issued s
5、ince publication DateComments Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 22:17:14 MDTNo reproduction or networking permitted without license from IHS -,-,- Reference number ISO 15490:2008
6、(E) INTERNATIONAL STANDARD ISO 15490 Second edition 2008-01-15 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 des cramiques monolithiques temprature
7、 ambiante BS ISO 15490:2008 Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 22:17:14 MDTNo reproduction or networking permitted without license from IHS -,-,- ii Copyright British Standards In
8、stitution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 22:17:14 MDTNo reproduction or networking permitted without license from IHS -,-,- iii Contents Page Foreword iv 1 Scope . 1 2 Normative references. 1 3 Terms and definitions
9、. 1 4 Principle. 2 5 Apparatus 2 6 Test specimen. 2 7 Procedures 3 8 Calculation. 5 9 Report 5 Annex A (informative) Shape and dimensions of test specimen 7 Bibliography. 10 BS ISO 15490:2008 Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=
10、Boeing Co/5910770001 Not for Resale, 08/14/2008 22:17:14 MDTNo reproduction or networking permitted without license from IHS -,-,- iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing In
11、ternational 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
12、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 techn
13、ical 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
14、 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 15490 was prepared by Technical Committee ISO/TC 206, Fine ceramics. This second edition cancels and replaces the f
15、irst edition (ISO 15490:2000), which has been technically revised. BS ISO 15490:2008 Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 22:17:14 MDTNo reproduction or networking permitted without
16、 license from IHS -,-,- 1 Fine ceramics (advanced ceramics, advanced technical ceramics) Test method for tensile strength of monolithic ceramics at room temperature 1 Scope This International Standard specifies the test method for determining the tensile strength under uniaxial loading of monolithic
17、 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 generation. 2 Normative references Th
18、e 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 3611:1978, Micrometer callipers for external me
19、asurement ISO 7500-1:2004, Metallic materials Verification of static uniaxial testing machines Part 1: Tension/compression testing machines Verification and calibration of the force-measuring system 3 Terms and definitions For the purposes of this document, the following terms and definitions apply.
20、 3.1 tensile stress value of tensile force applied to a test specimen divided by the original cross-sectional area of the gauge part of a test specimen 3.2 tensile strength maximum tensile stress applied to a test specimen during a tensile strength test 3.3 maximum tensile force maximum force applie
21、d to a test specimen during a tensile strength test 3.4 gauge section parallel portion of the test specimen having the same cross-section as its middle part 3.5 gripped region end part of a test specimen which is held by the gripping device of a tensile test machine BS ISO 15490:2008 Copyright Briti
22、sh Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 22:17:14 MDTNo reproduction or networking permitted without license from IHS -,-,- 2 3.6 gripping device device to hold a test specimen and to transfer a force
23、 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 axial misalignment, divided by the average strain 3.8 percent bending bending strain component times 100 3.9 strain fractional increase in l
24、ength when a test specimen is loaded in tension 3.10 breaking force force at which fracture occurs 4 Principle The test consists of applying a tensile force to a test specimen by uniaxial loading until fracture, for the purpose of determining the tensile strength. 5 Apparatus 5.1 Tensile testing mac
25、hine The testing machine used for the tensile test shall conform to the requirements of lSO 7500-1:2004, Class 1. 5.2 Gripping devices Every endeavour shall be made to ensure that test specimens are held in such a way that the force is applied as axially as possible (see 7.2). For this purpose, vari
26、ous types of gripping device may be used. NOTE The gripping devices that have been applied to measuring tensile strength of monolithic ceramics and their advantages/disadvantages are shown in ASTM C 1273. 6 Test specimen 6.1 Shape and dimensions The shape and dimensions of the test specimens depend
27、on several factors, including the 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 s
28、o that the tensile stress is applied 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 dimensiona
29、l accuracy greater than 0,5 %. The test specimens that have been applied to testing fine ceramics are shown in Annex A. BS ISO 15490:2008 Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 22:17:
30、14 MDTNo reproduction or networking permitted without license from IHS -,-,- 3 6.2 Test 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-roughness-related
31、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 to the appl
32、ied tensile stress. Care shall be taken in storage and handling of finished test specimens to avoid the introduction of random and severe flaws. NOTE In some cases, the final surface finish might not be as important as the subsurface damage produced during the grinding process. This damage is not re
33、adily observed or measured. 6.3 Number 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 with fr
34、actures outside the gauge section shall not be included in the calculation of the mean or standard deviation, but may be included in the calculation of Weibull statistics as censored tests. NOTE The number of test specimens needed for the test depends on the precision required for estimating the par
35、ameters of strength properties. 7 Procedures 7.1 Test 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 t
36、he multiple measurements shall be used in calculating the cross-sectional area. 7.2 Axial 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 sha
37、ll be symmetrically located about the longitudinal midpoint of the gauge section, and shall be separated by at least 3/4 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 longi
38、tudinal 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 (2 o). Ideally, the verification shall be made for all the individual test specimens to be tested. However, if this is not p
39、ossible or 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. Mount the test specimen in the gripping device and
40、apply a 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 the percent bending using the following equation: BS ISO 15490:2008 Copyright British Standards Institution Provided by IHS under license
41、 with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 22:17:14 MDTNo reproduction or networking permitted without license from IHS -,-,- 4 22 1/2 1324 1234 ()() 2100B + = + for four gauges and 2221/2 1231 22 33 1 123 () 2100B + = + for three gauges, where B is the pe
42、rcentage bending; 1, 2, 3 and 4 are the 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 with a percentage bending of 5 % or less is require
43、d 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 least at the beginning and end of each test series. Veri
44、fication 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 the uniform gauge section. NOTE Information on bendi
45、ng in tensile strength tests is available in ASTM C 1273-05, Annex. 7.3 Test mode and rates Various test modes, including force, 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 th
46、an 10 s in order to minimize environmental effects and thus obtain the intrinsic value of the ultimate tensile strength. In the case of evaluating rate effects, lower rates can be used. In all cases, the test mode and rate shall be reported. The most common test mode is displacement control. In this
47、 case, cross-head speeds greater than 0,008 33 mm/s (0,5 mm/min) are recommended. For force 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 th
48、e test. 7.4 Recording After conducting the test, the breaking force 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 microscope to determine the position and nature of the fracture origin. BS ISO 15490:2008 Copyright British Standards