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MM: Fachverband Metall- und Materialphysik

MM 25: Interface Controlled Properties, Nanomaterials and Microstructure Design IV

MM 25.3: Talk

Tuesday, March 19, 2024, 12:15–12:30, C 230

Nano-scale investigation of fractal abnormal grains and grain boundaries in Pd-Au using atom probe tomography — •Johannes Wild¹, Torben Boll^1,2,3, Fabian Andorfer⁴, Svetlana Korneychuk^2,3, Jules M. Dake⁴, Dorothée Vinga Szabo^1,2,3, Stefan Wagner¹, Carl E. Krill III⁴, and Astrid Pundt^1,2 — ¹Institute for Applied Materials (IAM-WK), Karlsruhe Institute of Technology — ²Institute of Nanotechnology (INT), Karlsruhe Institute of Technology — ³Karlsruhe Nano Micro Facility (KNMFi), Karlsruhe Institute of Technology — ⁴Institute of Functional Nanosystems, Ulm University

Nanocrystalline (NC) Pd-Au prepared by inert gas condensation exhibits fractal abnormal grain growth during heat treatment. The resulting microstructure is characterized by a bimodal grain size distribution with micrometer-sized grains (FG) embedded in a matrix of NC grains (NG). To elucidate this unusual manifestation of grain growth, we extracted sharp tip samples from FG and NG bulk regions, as well as from the FG-FG and FG-NG interface regions and analysed them with a LEAP 4000X HR atom probe. The NG region exhibited an O content that was multiple times higher in comparison with the FG region. Cluster analysis confirmed the presence of a multitude of O-rich clusters in the NG, but not in the FG region. Furthermore, the reconstructions of the boundary regions revealed an unexpected diversity of host and contamination element distributions at the FG-FG and FG-NG interfaces.

Keywords: abnormal grain growth; fractal; atom probe tomography