Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 17: Poster Session
MM 17.79: Poster
Montag, 26. März 2012, 17:00–19:00, Poster B
Reactive Diffusion and Stress in Core-Shell Nanostructures — Zoltan Erdelyi1, Christian Buchholz2, and •Guido Schmitz2 — 1Department of Solid State Physics, University of Debrecen, Hungary — 2Wilhelm-Klemm-Str. 10, 48149 Münster, Germany
In comparison to planar multilayers, core-shell and hollow nanospheres show remarkably different kinetics of solid state reaction, since much higher levels of reaction-induced stress can develop in closed spherical geometries. We present a completely analytical model to calculate the development and anisotropic plastic relaxation of stress during reactive diffusion in spherical geometry. The complex model can be considered as a generalization of Stephenson's model (Acta Metallurgica 1988; 36:2663). It is demonstrated that growth rates in nanometric spherical diffusion couples may switch from fast Darken interdiffusion to slow Nernst-Planck interdiffusion regime in dependence of layer stacking sequence. In triple layers A/B/A, the reaction rate at both interfaces may become remarkably different as has been indeed observed experimentally (Schmitz et al. Acta Mat. 2009; 57:2673) by atom probe tomography.