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M: Metallphysik

M 33: Postersitzung

M 33.30: Poster

Donnerstag, 29. März 2001, 15:15–19:00, Foyer S4, CCH

Misfit disclinations and amorphous intergranular films in nano- and polycrystalline films — •Anna Kolesnikova, Ilya Ovid’ko, Anna Reizis, and Alexei Romanov — Institute of Problems of Mechanical Engineering, Russian Academy of Sciences, Bolshoj 61, Vas.Ostrov, St.Petersburg 199178, RUSSIA

The two theoretical models are proposed which describe generation of misfit disclinations at interphase boundaries and formation of amorphous intergranular layers in nanocrystalline and polycrystalline films. The former model focuses on a new physical mechanism for relaxation of misfit stresses in nanocrystalline and polycrystalline films, which is the formation of misfit disclinations at interphase (film/substrate) boundaries. It is shown that the formation of misfit disclinations is energetically favourable, if the film thickness ranges from 0 to some optimum value h0. In the framework of the second model, the driving force for the formation of an amorphous intergranular layer is revealed and estimated, which is related to changes in the elastic energy density of a conventional grain boundary that transforms into the amorphous layer. Predictions of the model are in satisfactory agreement with the corresponding experimental data reported in the scientific literature. Support of INTAS grant 99-1216 is acknowledged.