1、BSI Standards PublicationBS ISO 17139:2014Fine ceramics (advancedceramics, advanced technicalceramics) Thermophysicalproperties of ceramiccomposites Determinationof thermal expansionBS ISO 17139:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 17139:2014.Th
2、e UK participation in its preparation was entrusted to TechnicalCommittee RPI/13, Advanced technical ceramics.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users
3、 are responsible for its correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 77171 2ICS 81.060.30Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of the
4、Standards Policy and Strategy Committee on 30 June 2014.Amendments issued since publicationDate Text affectedBS ISO 17139:2014 ISO 2014Fine ceramics (advanced ceramics, advanced technical ceramics) Thermophysical properties of ceramic composites Determination of thermal expansionCramiques techniques
5、 Proprits thermophysiques des composites cramiques Dtermination de la dilatation thermiqueINTERNATIONAL STANDARDISO17139First edition2014-06-15Reference numberISO 17139:2014(E)BS ISO 17139:2014ISO 17139:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All rights reserved. U
6、nless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at th
7、e address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 17139:2014ISO 17139:2014(E) ISO 2014 All rights reserved iiiContent
8、s PageForeword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 24.1 General . 24.2 Direct measurement . 24.3 Differential method . 25 Apparatus . 25.1 Construction materials 25.2 Heating and cooling device. 25.3 Temperature measurement . 25.4 Test piece mounting . 25.5 Sy
9、stem for measuring and recording the thermal expansion 35.6 Test piece measurement . 36 Specimens 36.1 Test pieces . 36.2 Reference pieces 36.3 Dimensions . 37 Procedure. 48 Calculations 58.1 Direct measurement . 58.2 Differential method . 59 Test report . 6Annex A (normative) Direct measurement app
10、aratus 9Annex B (normative) Differential type measurement apparatus .11Bibliography .12BS ISO 17139:2014ISO 17139:2014(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International St
11、andards 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
12、 take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In
13、 particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements
14、 of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (s
15、ee www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence
16、to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 206, Fine ceramics.iv ISO 2014 All rights reservedBS ISO 17139:2014INTERNATIONAL STANDARD ISO 17139:2014(E)Fine ceramics (ad
17、vanced ceramics, advanced technical ceramics) Thermophysical properties of ceramic composites Determination of thermal expansion1 ScopeThis International Standard describes methods for the determination of linear thermal expansion characteristics of ceramic matrix composite materials up to 2 300 K,
18、and is applicable to 1D, 2D, and nD materials.The method describes general principles of construction, calibration, and operation of the equipment.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application
19、. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO/IEC 17025, General requirements for the competence of testing and calibration laboratoriesIEC 60584-1, Thermocouples Part 1: Reference
20、tables3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1linear thermal expansionpositive or negative change in one dimension that occurs when a material is subjected to a change in temperature3.2linear thermal expansion coefficient at temperature
21、Tderivative of the length L with respect to temperature at the temperature T, divided by the length at temperature TT=1LdLdT3.3mean linear thermal expansion coefficient between temperatures T1and T2linear thermal expansion between temperatures T1and T2divided by the temperature increment T1to T2and
22、the length at temperature T1 TTLT LTLT TT12211211,()=() ()()()3.4representative volume elementRVEminimum volume which is representative of the material considered ISO 2014 All rights reserved 1BS ISO 17139:2014ISO 17139:2014(E)4 Principle4.1 GeneralA test piece is heated and subsequently cooled, eit
23、her at a specified uniform rate or using defined temperature increments. Its change of length and its temperature are measured continuously, or at regular frequent intervals during the imposed temperature cycle.One of two methods can be used to determine the linear thermal expansion coefficient, eit
24、her by direct measurement or by a differential method.4.2 Direct measurementIn this method, the variation in length of the test piece is measured directly. It is necessary to know the change in dimensions of the test piece support system by previous calibration.The test piece is placed in a specimen
25、 holder and is made to contact a displacement transducer by using a push rod, made of the same material as the holder. This assembly is put in a furnace. The differential expansion between the test piece and the test piece holder is measured during the increase and the decrease in temperature.The ap
26、paratus is shown in Figure 1.4.3 Differential methodThis method consists of measuring the changes in length between a reference piece (6.2) and the test piece. It is not therefore necessary to know the change in dimensions of the test piece support system.The apparatus is shown in Figure 2.5 Apparat
27、us5.1 Construction materialsThe test piece holder and the push rod shall be made from thermomechanically stable materials of the same type, which shall be chemically inert and thermally compatible with the test piece material under the environmental conditions of the test.NOTE For temperatures above
28、 1 400 C, it is necessary to employ a vacuum or inert gas atmosphere, with a non-oxide material appropriate for the test environment, such as a grade of dense graphite.5.2 Heating and cooling deviceFurnace, capable of working in a controlled atmosphere when required, and of controlling the temperatu
29、re of the test piece to within 1 % of its mean temperature, expressed in K.5.3 Temperature measurementThermocouples, in accordance with IEC 60584-1, subject to the upper temperature requirements and environmental consideration, except for tungsten-rhenium couples which may be used at higher temperat
30、ures but are not covered by IEC 60584-1, should be individually calibrated. For temperature in excess of 2 000 K, infrared detectors or any suitable device may be used.5.4 Test piece mountingThe device used shall allow free axial movement of the test piece and of the reference piece in case of diffe
31、rential measurement. The mechanical environment shall minimize stresses. For vertical 2 ISO 2014 All rights reservedBS ISO 17139:2014ISO 17139:2014(E)measurement apparatus, the test pieces shall be free standing and mechanically stable on the end-plate. For measuring apparatus which is horizontal or
32、 inclined to the horizontal, the sideways movement or twist of the test piece shall be restricted, without any restriction of axial movement, by a suitable arrangement.5.5 System for measuring and recording the thermal expansionSystem, capable of measuring displacements to an accuracy better than 0,
33、1 m. The system shall allow recording of the test piece temperature and the displacement simultaneously. The system for measuring of displacements shall be periodically calibrated in accordance with Annex A for direct measurement or Annex B for differential measurement.5.6 Test piece measurementDevi
34、ce for measuring the test piece dimensions, with an accuracy better than 0,05 mm (e.g. micrometer in accordance with ISO 3611 or callipers in accordance with ISO 6906).6 Specimens6.1 Test piecesThe dimensions of the test pieces depend on the type of apparatus used. For differential measurements, the
35、 test piece and the reference piece (6.2) shall have the same length L0(see Table 1).The test piece shall be cut in such a way that the axis of desired measurement is related to the principal fibre orientations in accordance with agreement between parties to the measurement.The end-faces of the leng
36、th of the test piece shall be plane, parallel to each other, and perpendicular to the long axis.6.2 Reference piecesReference materials shall be chosen so that their properties are as close as possible to the properties of the material to be tested. The reference piece shall have a volume of the sam
37、e order and, if possible, shall have the same dimensions as the test piece (see Table 1).For measurement at high temperature (over 2 000 K) under inert atmosphere, reference materials generally used are either tungsten or highly purified graphite. Reference materials shall be procured from a certifi
38、ed laboratory.6.3 DimensionsSee Table 1. ISO 2014 All rights reserved 3BS ISO 17139:2014ISO 17139:2014(E)Table 1 Recommended test piece dimensionsDimensions in millimetresMaterial with small RVE (3.4) such as 1D or 2DMaterial with large RVE (3.4) such as nD (n 3)TolerancesL0,total length 30 70 0,2B,
39、 width 7 Depending on material and equipmenth, thickness Depending on material and equipmentDepending on material and equipmentDepending on material and equipment, diameter - 30 Parallelism 0,01 0,01 A test piece volume of a minimum of 5 RVE (3.4) is recommended.The shape and dimensions of the test
40、piece depend on the structure of reinforcement. In the case of material such as 3D, a large test piece is often necessary when the representative volume element is important.For nD (n 3) composites with large RVE, thick beam specimens or cylinders with diameter are recommended. If dimensions differe
41、nt from the recommended ones are used, specimen volume shall be larger than 5 RVE. Tolerances: dimensions: 0,2 - Parallelism: 0,05.7 ProcedureIn order to simplify calibration procedures, test pieces and reference pieces of the same length should be used. If reference and test pieces have different l
42、engths, then it is necessary to take into account a base line shift. In this case, refer to EN 821-1. Measure the original length of the test piece at room temperature with devices (5.6).The accuracy shall be better than 0,05 mm for length of 10 mm and above, and 0,02 mm for length lower than 10 mm.
43、 Make sure that the equipment has been calibrated for the type of material prior to the test, according to the procedure described in Annex A for direct measurement determination of S and A(), and in Annex B for differential measurement (S and ). Introduce the test piece in test system and provide a
44、 good contact between the push rod and the test piece. The force to apply on the specimen depends on the test system and material, but values lower than 1 N are generally sufficient. Proceed with heating or cooling at a rate of between 1 K/min and 5 K/min, ensuring a fairly constant temperature grad
45、ient along the test piece. If the temperature is changed by steps, the hold temperature shall be maintained until the length of the test piece shows no change for at least 5 min before the measure. Record temperature T and displacement x.In case of large test pieces, a stepwise temperature rise is r
46、ecommended.The mean linear thermal expansion coefficient shall be calculated as the average from the results of tests on three test pieces.Push rod for test should not have any reaction with the test piece and the reference.4 ISO 2014 All rights reservedBS ISO 17139:2014ISO 17139:2014(E)8 Calculatio
47、ns8.1 Direct measurementCalculate the change in length, l, of a length of the sample holder material equal to the original test piece length L0, from Formula (1):lL TTA=()021 (1)using the calculated value of l, the change in length of L of the specimen is obtained from the measured displacement Sx:L
48、Sxl=+ (2)Calculate the mean linear thermal expansion coefficient of the test piece material from Formula (3): =()LLT T02 1(3)whereis the mean linear thermal expansion coefficient of the test piece material, in K1;Ais the mean linear thermal expansion coefficient correction for the apparatus over the
49、 temperature range used. It is determined from calibration (see Annex A);L0is the initial length of the test piece at room temperature, in mm;x is the recorded displacement (in mm, volt, etc.) over the temperature range;S is the measurement sensitivity of the displacement recording system;l is the change in length of the sample holder material, in mm;L is the change in length of the test piece, in mm;T2T1is the temperature interval in K for which the change in length is measur
