Scripta METALLURGICA Vol. 24, pp. 1547-1552, 1990 Pergamon Press plc et MATERIALIA Printed in the U.S.A. All rights reserved MICROSTRUC'IZIRAL STUDY OF STATIC AND DYNAMIC DEFORMED POLYCRYSTALLINE COPPER BY X-RAY DIFFRACTION PROFILE ANALYSIS Ning Jl and Jean-Lou LEBRUN LMMM, UA CNRS 1219, ENSAM, 151 Bd. de l'H6pital, 75013 Paris, France (Received April 25, 1990) (Revised June 5, 1990) INTRODUCTION To understand the response for a material imposed on a mechanical loading, it is necessary to study the material's microstructural evolution concurrendy with macroscopical tests. In particular, knowledge on plastic deformation is strongly advanced with dislocation observations and analysis on Transmission Electron Microscope (T.E.M.). Nevertheless, there are few studies carried out for deformed materials in dynamic conditions (1,2). Since the 1950's, it is well known that profile analysis of broadened X-ray diffraction peak could be used to study microsu'uctural evolution for plastic deformed crystalline materials. This technique is applicable nondesu'uctively to "macroscopic" volumes of bulk material. It is complementary to T.E.M. in so far as it provides reliable information especially for high dislocation densities that are not easily investigated by T.E.M. technique (3-5). In this study on polycrystalline copper, we try to follow microstructural evolution of dynamic deformation comparing with results obtained in the case of static deformation by the use of broadened X-ray diffraction profile analysis technique. The results obtained by profile analysis will be compared with the information acquired by other techniques, such as T.E.M. observation, stored energy measurement. MATERIALS AND TREATMENTS Polycrystalline copper specimens used in our study are relatively pure (99.999% Cu). Cold-rolling to 30% reduction and an anneal treatment (at 450°C in 6 h after rolling) are carried out on the raw material. Its grain size is about 80 pro. Two mechanical plastic deformation modes are taken to have a varied range of true deformation: - static compression: deformation rate is about 5"10-4 s -t - dynamic compression: the utilization of a Hopkinson bar permits us to obtain a high plastic deformation rate between 800 and 4000 s-t. Note: This present study has been carried out on samples prepared for a previous study by F. Cheval and L. Priester (Scripta Metallurgica, Vol. 23, pp 871-876.) 1547 0036-9748/90 $3.00 + .00 Copyright (c) 1990 Pergamon Press plc