Regensburg 2022 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 6: Computational Materials Modelling: Defects / Alloys

MM 6.7: Vortrag

Montag, 5. September 2022, 17:30–17:45, H44

Using MD simulations to better understand and control self-propagating reactions in Al-Ni multilayers — •Fabian Schwarz and Ralph Spolenak — Laboratory for Nanometallurgy, Department of Materials, ETH Zürich, CH-8093 Zürich, Switzerland

Reactive multilayers are capable of releasing large amounts of heat in a short time, making them a possible tool for energy storage or joining applications. Molecular Dynamics (MD) simulations can be used as a tool to study the front propagation, while varying certain system parameters. We study the influence of the crystal structure on the reaction front propagation in Al-Ni multilayers by looking at various microstructures, such as amorphous, single crystal or different grain structures. We found that crystallinity has a significant impact on the front propagation speed, which is likely related to different diffusion mechanisms. The more disordered the individual layers become, e.g., by increasing the grain boundary density, the higher is the resulting propagation speed. Furthermore, we study the influence of a premixed interlayer at the interface on the reaction propagation. For this, premixed interlayers with different, namely homogeneous, gradient and s-shaped profiles are studied and compared to existing experimental results. Beyond better understanding of the premixed interlayer, we show that it can be used to control the front propagation speed in reactive multilayers. Furthermore, we show that the heat of crystallization of amorphous AlNi to B2-AlNi alone is high enough for a self-propagating reaction to occur.