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M: Metallphysik

M 18: Nanoskalige Materialien I

M 18.2: Vortrag

Samstag, 5. März 2005, 09:30–09:45, TU H111

MICROSTRUCTURAL EVOLUTION OF ULTRA-FINE GRAINED ECAP COPPER DURING ANNEALING — •Sheila Bhaumik, Myrjam Winning, and Günter Gottstein — Institut für Metallkunde und Metallphysik, RWTH Aachen, Kopernikussrt. 14, 52056 Aachen

The reduction of the grain size down to the submicrometer regime opened new and fascinating aspects for research in several fields of materials science. One of the most important characteristics of ultra-fine grained or nanocrystalline materials is that with decreasing grain size the ratio between surface and volume strongly increases, so that the properties of the internal interfaces become more and more important. On the other hand volume effects like dislocation multiplication are hindered or even suppressed. The structure as well as the thermal stability of massive ultra-fine grained copper was investigated. The used samples were produced by severe plastic deformation using the ECAP method (equal channel angular pressing). The influence of grain boundary triple junctions and the influence of the deformation character of the microstructure on the thermal behavior was investigated by ex-situ investigations using SEM/EBSD for increasing number of the ECAP passes. The experiments were designed to yield information on the correlation between the microstructure of ultra-fine grained materials and its stability against recrystallization and grain growth.