SKM 2023 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 27: Hydrogen in Materials

MM 27.8: Vortrag

Mittwoch, 29. März 2023, 12:15–12:30, SCH A 215

Visualizing radiation-induced damage by Hydrogen/Deuterium — •Aparna Saksena, Binhan Sun, Heena Khanchandani, and Baptiste Gault — Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straβe 1, Düsseldorf 40237, Germany

Atom probe tomography (APT) is now extensively used to measure the local chemistry of materials. APT proceeds by field evaporating a sharp, needle-shaped specimen with a radius * 50 nm, often prepared by focused ion beam (FIB) milling. The interaction of the ion beam at high currents is known to amorphize crystalline materials by changing the lattice and creating vacancies. Therefore, a platinum protective layer and a low-energy ion shower are routinely used to avoid or remove the damaged layer from the specimen. Additionally, for investigating the local chemistry of defects such as interfaces via APT, transmission Kikuchi diffraction (TKD) can be performed during milling steps. The damage resulting from these techniques is considered negligible. Here, we use deuterium charging to probe the damage associated with specimen preparation as vacancies are known to be strong trapping sites for hydrogen/deuterium. We analyzed a medium Mn steel containing austenite (fcc) and ferrite (bcc). APT specimens were charged in a deuterium gas atmosphere, and the distribution of deuterium shows clusters of point defects after Pt deposition, conventional Ga-FIB preparation, and TKD. These deuterium-rich clusters are sequentially minimized by systematically eliminating these preparation-induced damages.