Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 24: Transport & Diffusion II

MM 24.2: Vortrag

Dienstag, 12. März 2013, 12:00–12:15, H26

Thermal stability of fast diffusion pathways in ECAP-deformed Ag — •Jochen Fiebig¹, Sergiy Divinski¹, Werner Skrotzki², and Gerhard Wilde¹ — ¹Institute of Materials Physics, University of Münster, Münster, Germany — ²Institute of Structural Physics, Dresden University of Technology, Dresden, Germany

We performed a systematic study of grain boundary self-diffusion in ultrafine grained silver produced by equal channel angular pressing (ECAP) using the radiotracer method (^110mAg-tracer solution) in combination with parallel sectioning by microtome slicing. The grain boundary diffusion was measured depending on the deformation state and the resulting profiles unambiguously revealed the existence of grain boundaries with enhanced excess energy density, i.e. ’high-energy’ grain boundaries. Based on this result, we focused on the thermal stability of these specific grain boundaries. Therefore, the diffusion properties after different heat treatments were studied and the microstructure was analyzed with respect to structural elements that survived the heat treatment. Additionally, calorimetric measurements were performed. Applying Borisov’s formalism [1] the excess energy of high-energy grain boundaries was determined. The energy of general high-angle grain boundaries was measured to be about 0.5 J/m². The grain boundary energy of high-energy grain boundaries is about 10 % to 20 % higher.
[1]V.T. Borisov, V.T. Golikov, and G.V. Shcherbedinsky, Phys. Metall. Metallogr. 17, 881 (1964)