Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 24: Transport & Diffusion II

MM 24.1: Vortrag

Dienstag, 12. März 2013, 11:45–12:00, H26

Diffusion and microhardness in ultrafine grained nickel produced by high-pressure torsion — •Simon Trubel, Sergiy Divinski, Martin Peterlechner, Gerrit Reglitz, Jörn Leuthold, Matthias Wegner, Christian Simon, and Gerhard Wilde — Institut für Materialphysik, Wilhelm-Klemm-Str. 10, 48149 Münster

Ultrafine grained and nanocrystalline materials produced by methods of severe plastic deformation have roused a growing interest in science and technology due to their unusual property combinations. Here, tracer diffusion is used as a sensitive probe to determine how the internal interfaces in a material are affected by severe deformation. Nanoindentation was applied to obtain information about the local mechanical properties of the material and their evolution with annealing temperature. EBSD (electron backscatter diffraction) and TEM (transmission electron microscopy) were utilized for microstructure examination. Nickel material of 99.6 wt. % purity was subjected to high pressure torsion (HPT), performing several rotations under a quasi-hydrostatic pressure of 2 GPa. By this treatment, ultrafine grained Ni is produced. Subsequently, grain boundary self-diffusion was measured at several temperatures applying the radioactive isotope 63Ni. The measurements indicate that the specific grain boundary diffusivity is significantly enhanced. The results of the complementing methods are discussed in the context of grain boundary structure modifications through severe plastic deformation.