P. Holler· V. Hauk· G. Dobmann C. O. Ruud . R. E. Green (Eds.) Nondestructive Characterization of Materials Proceedings of the 3rd International Symposium Saarbriicken, FRG October 3-6, 1988 Organized by Deutsche Gesellschaft fur zerstorungsfreie Priifung e.Y. (DGZiP), Berlin and Fraunhofer-Institut fur zerstorungsfreie Priifverfahren (!ziP), Saarbriicken With 609 Figures Springer-Verlag Berlin Heidelberg NewY ork London Paris Tokyo Hong Kong Prof. Dr. Paul Holler Prof. Dr. Viktor Hauk Fraunhofer Institut Institut fUr Werkstoffkunde fUr zerstorungsfreie Priifverfahren Rhein. Westf. Technische Hochschule Universitat, Gebaude 37 5100 Aachen 6600 Saarbriicken 11 FRG FRG Prof. Dr. Clayton O. Ruud Dr. G. Dobmann 159 Materials Research Laboratory Fraunhofer Institut The Pennsylvania State University fUr zerstorungsfreie Priifverfahren University Park, Pennsylvania 16802 Universitat, Gebaude 37 USA 6600 Saarbriicken 11 FRG Robert E. Green, Jr. Center for Nondestructive Evaluation The Johns Hopkins University Baltimore, Maryland 21218 USA ISBN -13: 978-3-642-84005-0 e-ISBN-13 :978-3-642-84003-6 DOl: 10.1007/978-3-642-84003-6 This work is subject to copyright. All rights are reseIVed, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, re-use of illustrations, recitation, broadcasting, reproduction on microfilms or in otherways,and storage in data banks. Duplication ofthis publication or parts thereofis only permitted under the provisions of the German Copyright Law ofSeptember9, 1965, in its version ofJ une 24, 1985,and a copyright fee must always be paid. Violations fall underthe prosecution act of the German Copyright Law. © Springer-Verlag Berlin Heidelberg 1989 Softcoverreprint of the hardcover 1st edition 1989 The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and there fore free for general use. 216113020543210 Preface Engineering structures for reliable function and safety have to be designed such that operational mechanical loads are compensated for by stresses in the components bearable by the materials used. Vhat is "bearable"? First of all it depends on the properties of the chosen materials as well as on several other parameters, e.g. temperature, corrosivity of the environment, elapsed or remaining serviceable life, unexpected deterioration of materials, whatever the source and nature of such deterioration may be: defects, loss of strength, embrittlement, wastage, etc. DEFECTS and PROPERTIES of materials currently determine loadability. Therefore in addition to nondestructive testing for defects there is also a need for nondestructive testing of properties. The third type of information to be supplied by nondestructive measurement pertains to STRESS STATES under OPERATIONAL LOADS, i.e. LOAD-INDUCED plus RESIDUAL STRESSES. Residual stresses normally cannot be calculated; they have to be measured nondestructively; well-approved elastomechanical finite element codes are available and used for calculating load-induced stresses; for redundancy and reliability, engineers, however, need procedures and instrumentation for experimental checks. Three quantitative ndt-categories should be available for the qualification and/or quality assurance of structures during fabrication and operation: - ndt for DEFECTS (ndtd) - ndt for PROPERTIES (ndtp) - ndt for STRESSES (ndts) Ndtd and ndts are much further developed and more frequently applied than ndtp. In addition, the technical communities for ndtd and ndts are much larger than that for ndtp. National and international ndt conferences deal far more with ndtd than ndts and ndtp. In November 88 the second International Conference on Residual Stresses was held in Nancy (less than 60 miles from SaarbrUcken), at which 205 papers were presented and with 280 participants attending. Most contributions dealt with just one ndts-technique, X-RAY DIFFRACTION. Second place was occupied by relaxation techniques in which residual stresses are partially released by drilling holes or machining notches. Releasing strain is measured by arrays of small strain gauges (rosettes). For shallow bore holes or notches this RELAXATION TECHNIQUE is at most slightly destructive. Both techniques, X-ray diffraction and relaxation, measure strains which are directly related to the stress states to be measured by the second order elastic moduli. Unfortunately the major mechanical properties describe the nonelastic i.e. nonreversible -- behaviour of materials, which physically is not correlated to elastic behaviour; however, only testing in the elastic area is nondestructive. Consequently, it is due to physical reasons that ndtp is not possible for MECHANICAL properties in a direct manner as ndtd is for defects and ndts for stresses. (Nevertheless elastic moduli have become important ndt quantities; they carry information pertaining to the stiffness and microstructure of materials. Several papers were presented on this subject during the symposium). Other physical properties such as nonelastic mechanical properties -- electric, thermal, magnetic, etc. can be measured using ndt techniques. They strongly correlate with the microstructure of materials. Macroscopic nonelastic properties and behaviour of materials, especially metals, physically depend on solid solutions (alloys), microstructure (dislocations, precipitations, etc.) and stresses. Physical metallurgy deals with these dependencies and will continue research on them as long as optimization and development of materials exist. The situation at present: we do not have nd testing methods offering direct access to macroscopic mechanical properties and describing behaviour under loads,' however, we do have nd testing technology for microstructure (and microstresses). Moreover, physical metallurgists have the know-how to derive macroscopic properties from microstructural data measured nondestructively. The scenario described above is illustrated by two diagrams. The first diagram shows microstructural parameters and defects relevant to strength VII and toughness of materials plotted against their linear dimensions, resulting in the resolution needed for nondestructive materials characterization. A wide band from 10-10 to 10-2 is covered; the most important area for metals and ceramics and composites as well is 10-9 to 10-5• In the second diagram ndt techniques are plotted with the same abscissa. There are more ndt techniques for microstructures and defects above 10-5 than below; but those below 10-5 already provide access to the most important microstructures relevant for mechanical properties and early stages of deterioration. The nondestructive characterization (ndc) of materials by electromagnetic techniques was born at least 50 years ago. A few names of pioneers, for laboratory applications as well as for industrial testing should be mentioned (in alphabetical order): W.A. Black, F. Forster, W. Gerlach, W. Jellinghaus, H. Lange. One of these pioneers, F. Forster, has accepted our invitation to present a paper on the origin of electromagnetic methods. It is the merit of C.O. Ruud and R.E. Green that a series of symposia devoted to nondestructive materials characterization was started in 1983. This first symposium, held in Hershey Pennsylvania, was a considerable success. The same holds true for the second symposium, organized by J.F. Bussiere in Montreal. During a meeting of the organizing committee and the international advisory board held during the second symposium the representatives of several countries indicated their willingness and interest to host and organize the third symposium. The decision was made in favour of Saarbrlicken, FRG. The 3rd IS-NDC, organized by the DGZfP and the FhG-IzfP, was conducted in Saarbrlicken from October 3-6, 1988. 225 scientists from 14 different countries took part. 81 oral presentations were given, 15 of them were invited plenary lectures and 37 poster presentations complementing the comprehensive program. The panel discussion involving P. Adam, G. Nardoni, H. Schneider, M. G. Seitz, Ch. Thoma, F. TOnolini and R. Zeller was chaired by D. O. Thompson. R. Sharpe gave an evaluation of the conference in his concluding speech along with providing an outlook for future objectives and development trends. VIII We would like to especially thank the numerous ladies and gentlemen of the staffs at the DGZfP, Berlin, and at the Institut fUr zerstorungsfreie prUfverfahren, SaarbrUcken, for their untiring efforts in helping to organize and conduct this symposium. We would also like to extend our thanks to the members of the international advisory board and the organizing and program committees. The present proceedings volume contains 103 articles submitted by the authors. This represents the current level of knowledge in the field of Nne of materials. The editors would like to thank the authors for adhering to the restrictions on length imposed. This means that they were forced to concentrate on essential results, dispense with details and supplementary work. We would like.to thank Springer Verlag for their efforts in quickly publishing the volume. P. Holler V. Hauk G. Dobmann x I Z ) s / m t / c / ( e Z / ef IZ / , . -2 d Z / J 0 Z ds/ / 1 d / el/ / an I ZI II k fi/ I / I f microstructure I I I Micro/Macro stresses /ZZZZZZZZZ/I I Texture, anisotropy vlllllll III gra1in size fZZZZZZZ/I I inclusions fZ Z Z ZI I s /] / / / / / I cracks/cracW/////////I I layers E://////// I I 0-10-4 6 dimensions o ~/ZZZ/ZI I dislocations vllllllll precipitations !2:/Z/ZZJ I I pore/ / / / / / / / Blochwalls vZ ZJ 110-8 ar ~ s e Line Atom-distancZ ZI f: void -10 0 ....., (.) ,.... <D <D "C "'-<D 10.. :::s ....., (.) :::s ....., 10.. en 0 10.. .-(.) E 1 x - n ~ ~- y, ZI / - - m) near dimensions Ui·catt~ing I I I e7ZZ Z7ZJ I I Echo-defect detection Absor~tion Z / / / / / / / / / / / / / / 7 / /1 r j US-microscopy 7 Ph;t; o~tfc ~If,a::':nd I E:///////1 ----------mic micromagnetic, eddy current ZZZZZZZZZZZZZZZZ~ I current perturbatio~ZZZZZZI I NMR ~ZZZZZZ/ZZZZZZZZZ--I Micro-radio-and tomography fZZ////Z/ZZZZI I Macro-radio-and tomographIfZZZZZZZZZZI X-ray diffraction ////////////////7/////----------------- ----------------- 10 10 10-2 -4 -6 ( NOT for li [JJ sound velocity 7 7 Z Z Z Z ---f---ent Dyna-0 ~ZZZ --------f- 1V7------1-o-force ZZZZ) --f-1" 10 .. 8 rr~ 1 mZT u - -erZ ---dy cv --- --Th~Z-- 0 1=/Ed f- - ~ 0-1 tn CD ::s .-0" s:::: .c (,) CD I-C z 1 Table of Contents 1. Research Programmes Y.van der Eijk Presentation of the next BRITE-EORAH-Programme H.Pero (1989-1992) ••.••.•••••••••••••••••••••••••••••.•••••• 3 Y.Faul Materials Research-Programme of the Federal Ministry for Research and Technology (BMFT) •••••••••• 8 2. Ceramics H.Schmidt Properties, preparation and requirements to testing of ceramic materials ••••••••••••••••••••.••• 17 T.Kishi Material characterization of ceramics by K.Kitadate various nondestructive testing methods .••••••••••••• 26 E.Brinksmeier Requirements on nondestructive testing methods H.Siemer after machining of ceramics ••••••••••••••••••••••••• 36 H.G.Yobker P.S.Nicholson Ultrasonic nde of advanced ceramics ••••••••••••••••. 46 J.Goebbels Tomodensitometry with x- and gamma-rays ••••••••••••. 56 H.Heidt B.Illerhaus P.Reimers G.Schlieper Nondestructive density measurements in powder V.Arnhold metallurgy and ceramics ••••••••••••••••••••••••••••• 65 H.Dirkes Y.Sachse New developments for the ultrasonic character- K.Y.Kim ization of materials •••••••••••••••••••••••••••••••• 73 3. Composites S.Datta Graphite-magnesium elastic constants: H.Ledbetter Composite and fiber ••••••••••••••••••••••••••••••••• 83 D.Y.Fitting Monitoring of anisotropic material elastic A.V.Clark properties using ultrasonic receiving arrays •••••••• 91 M.J.Ehrlich Anisotropy measurements and indication of ply J.Y.Yagner orientation in composite materials using holo graphic mapping of large amplitude acoustic waves ••••••••••••••••••••••••••••••••••••••••••••••• 99