Berlin 2012 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 5: Transport and Diffusion I
MM 5.2: Talk
Monday, March 26, 2012, 10:30–10:45, H 1029
Temperature induced transitions of the grain boundary structure studied by radiotracer diffusion — •Sergiy Divinski1, Henning Edelhoff1, Sergey Prokofjev2, and Gerhard Wilde1 — 1Institute of Materials Physics, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany — 2Institute of Solid State Physics, Chernogolovka, Russia
Grain boundary diffusion of 110mAg in Cu near Σ 5 bicrystals is measured parallel and perpendicular to the ( 001 ) misorientation axis in both, C and B kinetic regimes after common Harrison’s classification. For the first time, the grain boundary diffusion coefficients of a single grain boundary in a true dilute limit of the solute concentration are determined in the C kinetic regime and the values of triple products P = s · δ · Dgb are measured in the B regime (here s and δ are the segregation factor and the diffusional grain boundary width, respectively). A significant anisotropy of the grain boundary diffusion is established which disappears at the temperatures above 823 K. This temperature corresponds also to a kink in the Arrhenius temperature dependence of the triple product. The phenomenon is discussed in term of a special-to-general transition of the grain boundary structure. The anisotropy of the product s · δ for a single grain boundary is determined. The effect of non-linear segregation on Ag diffusion in the Cu bicrystal is elucidated via controlled variation of the total amount of the applied tracer material.
The financial support by DFG is acknowledged.