Pii: S1359-6454(99)00268-2
نویسنده
چکیده
ÐHow the core structure of an interface dislocation network depends on both mis®t and bond strength across the interface is investigated. It is shown that, in principle at least, it is possible to assess the bond strength by investigating the atomic structure of the dislocation cores. As examples, the mis®tdislocation structures at Ag/Mn3O4, Cu/MnO interfaces formed by parallel close-packed planes of Ag or Cu and O obtained by internal oxidation were studied using HRTEM and lattice static calculations. The lattice static calculations are instrumental in indicating the possible dislocation network and their results served as input for HRTEM image simulations which are then compared with experimental HRTEM images. In addition, the in ̄uence of dissolution of a segregating element (Sb) in these systems was also studied using HRTEM. The in ̄uence on Mn3O4 precipitates in Ag is distinct, namely: (i) the initial precipitates, sharply facetted by solely {111}, are changed into a globular shape with sometimes also short {220} and (002) facets, (ii) a partial reduction of Mn3O4 into MnO occurs for a part of the precipitates. Further Sb appeared to prevent Oswald ripening of the precipitates. # 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.
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Pii: S1359-6454(99)00264-5
ÐThe grain boundary segregation of Bi in dilute polycrystalline Cu±Bi alloys was systematically studied as a function of temperature and composition. The temperature dependencies of the Gibbsian excess of Bi at the grain boundaries exhibited discontinuous changes at the temperatures close to, but dierent from the bulk solidus temperatures. The observed segregational phase transition was interp...
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متن کاملPii: S1359-6454(99)00280-3
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