Dresden 2017 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 8: Topical session: Interface-Controlled Microstructures: Mechanical Properties and Mechano-Chemical Coupling - Segregation and Embrittlement II

MM 8.4: Vortrag

Montag, 20. März 2017, 12:30–12:45, BAR 205

Investigations on Grain Boundary Segregation in Nanocryalline Materials with Atom Probe Tomography — •Rüya Duran and Guido Schmitz — Institut für Materialwissenschaft, Universität Stuttgart

Nanomaterials are not just opening new opportunities for improvement of materials, but also challenges in characterizing and understanding the changed atomic structures and the chemical and physical behavior within the material. Grain boundaries have the major influence on the properties. An important property is the segregation at these defects. The grain boundary interacts with solute atoms which change their chemical composition and change the boundary and so, the material properties. In this work, the temperature and concentration dependence of grain boundary segregation in Cu/Ni thin films is investigated. For the analysis the Atom Probe Tomography (APT) is used. With the APT a very high spatial resolution in all three dimensions is achieved which makes the analysis of such a fine defect more precise. Since the APT allows chemical analysis in single atom sensitivity, segregation to grain boundaries can be easily identified. With the knowledge of the chemical composition, concentration profiles can be formed from which the widths and also the amplitudes of the segregation zones can be determined. With a new evaluation method the data will be extracted by using a model function for the defect which is fitted to the point data to increase the spatial resolution and to avoid artefacts.