Berlin 2012 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 20: Topical Session Bulk Nanostrucured Materials IV - Microstructure and Characterization II

MM 20.1: Topical Talk

Tuesday, March 27, 2012, 10:15–10:45, H 0107

Stabilisation of nanocrystalline materials by defects — •Harald Rösner — Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, Germany

The stability of nanocrystalline materials is an important issue and of technological interest. Grain growth occurs in polycrystalline materials to reduce the grain boundary area and hence the total energy of the system. Therefore, the high density of interfaces in nanocrystalline materials is likely to provide a significant driving force for grain growth. However, grain growth can be suppressed by the presence of either impurities or defects. In this talk a comprehensive study of defect-stabilized nanocrystalline Pd using aberration-corrected transmission electron microscopy is presented. Local strains were quantified at grain interiors and interfaces (grain/twin boundaries, triple/quadruple junctions) using the geometric phase analysis; a technique that allows calculation of the in-plane components of the strain tensor. The results obtained suggest that rotational defects play a significant role as stabilising elements for nanocrystalline structures.