Berlin 2024 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 19: Topical Session: In Situ and Multimodal Microscopy in Materials Physics (joint session MM/KFM)
KFM 19.3: Vortrag
Mittwoch, 20. März 2024, 16:15–16:30, C 130
Strain mapping of a sigma 5(310) grain boundary in a Cu bi-crystal using scanning transmission electron microscopy — •Anoosheh Akbari1, Harald Rösner1, Esakkiraja Neelamegan1, Hui Ding2, Christian.H Liebscher2, Sergiy Divinskiy1, and Gerhard Wilde1 — 1Institute of Materials Physics, University of Münster, Münster, Germany — 2Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany
Grain boundaries play an important role in determining the physical properties of materials. With respect to diffusion, extended strain fields localized at GBs can modify atomic transport along GBs. In order to understand the effect of strain on GB diffusion in more detail, the evolution of strain along GBs under mechanical treatment is investigated. For this purpose, a Cu bi-crystal containing a sigma 5(310) GB was fabricated by a modified Bridgman technique, followed by annealing at 800 °C. The surface was mirror-liked polished subsequently followed by FIB lamella target preparation of the GB in cross-sectional view. The elastic strain along and around the GB was measured on a nanometer scale, using nano-beam diffraction patterns (NBDPs) acquired using a 1 nm STEM probe with grains oriented in zone axis conditions. A custom written code was employed to extract the strain maps. On the atomic scale, the strain was characterized using geometrical phase analysis applied to high resolution STEM images confirming the results obtained by NBDP. The analysis was finally extended to deformed samples.
Keywords: strain; grain boundary; transmission electron microscopy; diffusion; bi-crystal