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MM: Fachverband Metall- und Materialphysik
MM 19: Transport
MM 19.4: Talk
Tuesday, March 15, 2011, 14:45–15:00, IFW D
Diffusion in a Cu bicrystal with near Σ 5 grain boundary — •Henning Edelhoff1, Sergej Prokofjev2, Sergij Divinski1, and Gerhard Wilde1 — 1Institute of Materials Physics, University of Münster, Münster, Germany — 2Institute of Solid State Physics, Chernogolovka, Moscow region, Russia
For the overall understanding of kinetic processes along grain boundaries of polycrystalline and nanocrystalline materials it is essential to understand the processes in a single, well defined grain boundary. In this work, for the first time, the grain boundary diffusion of a solute is measured in a single grain boundary in the C kinetics regime according to the common Harrison classification. The radiotracer technique in combination with parallel sectioning by microtome is used to determine 110mAg diffusion rates in Cu Σ 5 (310) [001] bicrystal along and perpendicular to the <001> misorientation axis under formal conditions of the B-type and C-type regime.
These studies provided in the B-type regime the values of the triple product P = s · d · Dgb of the segregation coefficient s, the effective (diffusional) grain boundary width d and the grain boundary diffusion coefficient Dgb, with the latter being directly determined in the C-type regime. A moderate but measurable anisotropy of the grain boundary diffusion is established. The anisotropy of the product s · d, which could be related to a heterogeneous segregation of Ag in the grain boundary, is estimated.