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MM: Fachverband Metall- und Materialphysik

MM 4: Materials for the Storage and Conversion of Energy

MM 4.2: Vortrag

Montag, 17. März 2025, 10:30–10:45, H22

Hydrogen kinetics in HPT-deformed bulk Mg and Mg-based alloys — •Giorgia Guardi¹, Sabine Schlabach^1,2,3, Julia Ivanisenko², Stefan Wagner¹, and Astrid Pundt¹ — ¹Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM-WK), Karlsruhe, Germany — ²Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology (INT), Karlsruhe, Germany — ³Karlsruhe Institute of Technology (KIT), Karlsruhe Nano Micro Facility (KNMFi), Karlsruhe, Germany

Magnesium (Mg) is a light and abundant element that can store hydrogen with a gravimetric density of 7.6 wt. % and a volumetric density of 110 kg H/m³. Therefore, it is a highly promising hydrogen storage material for a sustainable energy economy. However, its technical use is hindered by an inherent kinetic blockade in magnesium hydride. A high content of grain boundaries is expected to improve hydrogen kinetics in Magnesium samples, particularly in the magnesium hydride phase. This can be achieved in bulk samples through the use of severe plastic deformation techniques, such as High-Pressure Torsion (HPT).

High-pressure torsion is not fully effective in reducing the grain size in pure bulk magnesium due to dynamic recrystallization. To overcome this lower limit to bulk magnesium grain size, Mg- 2.3 at.% Zn- 0.17 at. % Zr alloys are used, reaching a final grain size of approximately 100 nm after HPT. This study examines the impact of the sample’s microstructure on hydrogen kinetics. Hydrogen absorption is studied at room temperature by gas-phase and electrochemical hydrogen loading.

Keywords: Magnesium; Hydride; kinetics