Berlin 2012 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 47: Topical Session Modern Atom Probe Tomography III - Functional and Nanostructured Materials

MM 47.5: Vortrag

Donnerstag, 29. März 2012, 11:30–11:45, H 0107

Triple junction and grain boundary diffusion in the Ni/Cu system — •Mohammed Reda Chellali, Zoltán Balogh, and Guido Schmitz — Institut für Materialphysik, Westfälische Wilhelms Universität Münster; Münster (Germany)

A topological defect of the grain boundary structure, the so called triple junction, plays a dominant role for grain growth and atomic transport in nano-crystalline materials. By means of atom probe tomography measurement of atomic transport along triple junctions and grain boundaries became possible recently [1]. Heat treatment was chosen in the kinetic C-B regime according to generalized Harrison categories for the hierarchy of volume, grain boundary and triple junction transport. A significant dependence of the thickness of the grain boundaries on the annealing temperature in the range of 563-643 K is detected and taken into account to determine the activation energy along triple junctions. The determined energies are found to be 120 KJ/mol and 82kJ/mol along the grain boundaries and triple junctions respectively. Thus, triple junctions represent a significantly faster diffusion route than grain boundaries.

[1] M-R. Chellali, Z. Balogh, L. Zheng and G. Schmitz Scripta Mater. 65/4 (2011) 343