1、TECHNOLOGY TRENDS ASSESSMENT lSO/TTA 2 First edition 1997-04- 15 Tensile tests for discontinuously reinforced metal matrix composites at ambient temperatures Essais de traction pour composites 2 matrice renforcke de manike discontinue de mktal h temperatures ambiantes Reference number ISO/TTA 2:1997
2、E) ISO/TTA 2: 1997(E) CONTENTS Page FOREWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 EXEC
3、UTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv INTRODUCTION - VALIDATION EXERCISE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V MATERIAL
4、S AND TESTPIECES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V lARTiClPATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V DISCUSSIOlV OF RESULTS . 0.e. vi CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xii 1 . 2 . 3 . 4 . 5 . 6 e 7 e 8 . 9 . 10 . 11 . 12 . 13 . 14 . 15 . 16 . SCOPE . . . . . . . . . 0. 1 PRINCIPLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 DEFINITIONS .
8、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 SYMBOL DESIGNATIONS . . . . . . . . . . . . . . . . . . .
9、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 TESTPIECES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 DETERMINATION OF ORIGINAL CROSS-SECTIONAL AREA (SJ . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 MARKING THE ORIGINAL GAUGE LENGTH (L,) . . . . . . . . . . . . . . . . . . . .
11、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 ACCURACY OF TESTING APPARATUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 CONDITIONS OF TESTING . . . . . . . . . . . . .
12、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 DETERMINATION OF PERCENTAGE ELONGATION AFTER FRACTURE (AP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 DETERMINATION OF PROOF STRENGTH (NON-PROPORTIONAL EXTENSION) (Rp) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 DETERMINATION OF PROOF STRENGTH (TOTAL EXTENSION) (R,) . . . . . . . . . . . . . . . . . . . . 8 DETERMINATION OF YOUNGS MODULUS (E) . .
15、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 DETERMINATION OF PROPORTIONAL LIMIT (PL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 DETERMINATION OF TENSILE STRENGTH . . .
16、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 TEST REPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 ANNEXES A TESTPIECE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18、 . 11 B TEST REPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 C BIBLIOGRAPHY . . . . . . . . . . . .
19、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 0 ISO 1997 All rights reserved. Uniess otherwise specified, no patt of this publication ma
20、y be reproduced or utilized in any form or by any means, electronie or mechanical, including photocopying and microfilm, without Permission in writing from the publisher. International Organization for Standardization Case postale 56 l CH-121 1 Geneve 20 l Switzerland Internet central iso.ch x.400 c
21、ch; a=400net; p=iso; o=isocs; s=central Printed in Switzerland ii ISO ISO/lTA 2: 1997(E) 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 ou
22、t through ISO technical committees. Esch 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, govemmental and non-govemmental, in liaison with ISO, also take part in the work. ISO coll
23、aborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical Standardisation. To respond to the need for global collaboration on standardization questions at early stages of technological innovation, the ISO CounciI, following recommendations of the IS
24、O/IEC Presidents Advisory Board on Technological Trends, decided to establish a new series of ISO publications named Technology Trends Assessments” (ISO/ITA). These publications are the results of either direct cooperation with prestandardization organizations or ad hoc Workshops of experts concemed
25、 with standardization needs and trends in emerging fields. Technology Trends Assessments are thus the result of prestandardization work or research. As a condition of publication by ISO, ISO/TTAs shall not conflict with existing International Standards or draft International Standards (DIS), but sha
26、ll contain information that would normally form the basis of standardization. ISO has decided to publish such documents to promote the harmonization of the objectives of ongoing prestandardization work with those of new initiatives in the Research and Development environment. It is intended that the
27、se publications will contribute towards rationalization of technological choice Prior to market entry. This Technology Trends Assessment, ISO/TTA 2, has been developed by the Versailles Project on Advanced Materials and Standards (VAMAS) and is published under a Memorandum of Understanding concluded
28、 between ISO and VAMAS. It reports the results of the Technical Working Area (TWA) 15 of VAMAS, which has the task of investigating mechanical test methods for metal matrix composites and which retains the responsibility for the technical content of this ISO/TTA. Users of this ISO/TTA who would like
29、 information on the research project should refer to a recent report of VAMAS TWA 15 which was prepared by Dr B Roebuck, Dr L N McCartney and Dr J D Lord of the NPL under the leadership of Dr Steve J Johnson at Georgia Tech., Atlanta, USA. The ISO Technical Board approved the publication of this cla
30、ssification as an ISO/ITA in late 1995. Whilst ISO/TTAs are not Standards, it is hoped that they will be used as a basis for Standards development in future national and international standardization processes. In the particular case of ISO/TTA 2, the publication has been brought, in the first insta
31、nce, to the attention of ECISS/TCl, Tensile Testing Standards, for use in its Standardisation work. ISO/TTA 2: 1997(E) EXECUTIVE SUMMARY There is a need for a tensile testing Standard for discontinuously reinforced metal matrix composites (MMC). Use of the current ISO Standard for metals EN 10002 le
32、ads to unsatisfactory uncertainties in the property values measured, particularly for Youngs modulus and proportional limit. The measurement of Youngs modulus in MMC is important for several reasons: a Improvements in specific stiffness are an important driver in increasing the use of MMC over conve
33、ntional materials. An accurate knowledge of the engineering value of Youngs modulus is vital for preliminary design studies. W Proof stress measurements require a Prior knowledge of the Youngs modulus. If the material of interest has a high work hardening rate in the early Stage of yield then inaccu
34、racies in the Youngs modulus tan lead to significant inaccuracies in proof stress. 4 MMC have low proportional limits because of internal residual Stresses. It is important to be able to measure the proportional limit accurately and to assess the extent of yield at low strains. An accurate value of
35、Youngs modulus is required to obtain reliable values for the proportional limit. 4 Accurate measurements of Youngs modulus are required to give good fits to the constitutive expressions for the stress/strain data. Following analysis of the results of a UK exercise to examine the sources of uncertain
36、ty in the measurement of the tensile properties of Sic particulate reinforced Al alloys a draft procedure was written for tensile tests on particulate MMC at ambient temperatures. The draft procedure recommends appropriate testpiece dimensions, testing rates, methods of gripping and strain measureme
37、nt techniques. It also defines methods for measuring Youngs modulus, proportional limit, proof stress, tensile strength and elongation to failure. Significantly it contains a recommended proforma for the test report in anticipation of future database requirements. The draft procedure forms the basis
38、 of this ISO/TTA document. It was validated by two interlaboratory exercises, one through VAMAS (internationally) and one in the UK (led by NPL). The outcome of this Validation exercise is also summarised in the Introduction to the ISO/TTA document. The style of the draft procedure is similar to tha
39、t adopted for the current EN tensile testing Standards, EN10002 pt 1 (tensile tests for metals) and its sister document for Aerospace materials EN20024 part 1. ISO INTRODUCTION - VALIDATION EXERCISE ISOKTA 2:1997(E) Two Validation exercises were carried out to tonfirm the Utility of the draft proced
40、ure: VAMAS An intercomparison using the tensile testing draft procedure l was instigated under the guidance of the VAMAS Technical Working Area 15 on Metal Matrix Composites. One of the important objectives of VAMAS is to harmonise testing procedures intemationally. The current exercise included Org
41、ankations from the UK, USA, Japan, France, Spain and Germany. UK MMC Forum Another intercomparison was organised by NPL through a sub-committee of the UK FORUM on TEST METHODS for MMC. It included a subset of the organisations involved in the first UK exercise 2 which were Chosen to be representativ
42、e of industry, academia and research organisations. Appropriate testpieces were distributed by NPL to the participating organisations in each exercise together with copies of the draft tensile testing procedure. Esch Organisation tested 3-4 testpieces. The results were retumed to NPL for collation a
43、nd analysis. MATERIALS AND TESTPIECES VAMAS: The MMC was provided by ACMC Ltd (USA) and was in the form of extruded 2009 A1/20% Sic,. It was machined into dogbone rectangular testpieces (Type Tl l - 6 mm x 3 mm Cross section; 25 mm gauge length) by NRIM, Japan. UK Forum: An MMC and an unreinforced A
44、l matrix alloy were included in this study. The MMC was provided by AMC Ltd (UK) as rolled plate 2124 Al/20% SiCp. The Al alloy was provided by Alcan International Ltd as extruded bar (Alcan Cospray 2618). Both materials were machined at NPL into similar geometry testpieces as those used in the VAMA
45、S exercise (Type Tl 11). All the testpieces were machined using diamond (PCD) Tooling. PARTICIPATIORI VAMAS: NPL UK DRA (Farnborough) UK BAe (Warton) UK NIST USA NASA USA Inasmet Spain Bordeaux Univ BMW DLR TUHH Honda NRIM France Germany Germany Germany JP a an JP a an ISO/lTA 2: 1997(E) UK Forum: N
46、PL ERA DRA (Famborough) BAe (Warton) Lucas Oxford Univ Hi-Tee Sheffield Univ In reporting the results, alI the VAMAS participants were identified (by agreement); in the UK exercise participants remained anonymous and coded. DISCUSSION OF RESULTS GENERAL COMMENTS It is significant that alI the partic
47、ipants were able to use the draft procedure and results proforma without any major Problems and this clearly validated the draft procedure as a satisfactory written document. A number of comments were made on the tests and results by some of the participants and these remarks were used to make small
48、 changes to the procedure outlined in this document. YOUNGS MODULUS AND STRAIN MEASUREMENT METHOD The draft procedure for tensile testing l allowed three different types of analysis method to be used to calculate Youngs modulus. These are referred to as Ml, M2 and M3 and there are two subsets of M2
49、 M2A and M2B. These methods tan be summarised as follows. Ml - Graphical From a straight line drawn parallel to the initial Portion of a load/strain curve, idealIy plotted as close as possible to 45O to the strain axis on A3 Paper. M2 - Chorda1 (using Computer Software) From a straight line between two arbitrarily Chosen limits on the initial Portion of the stress/strain curve. M2A - M2B - direct straight line between the two Points. linear regression fit to the data between the Points. M3- Tangent wng Computer Software) This is the NPL recommen
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