Regensburg 2022 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 28: Transport in Materials: Diffusion / Electrical Transport & Magnetism
MM 28.5: Vortrag
Donnerstag, 8. September 2022, 11:15–11:30, H44
On correlations between local chemistry, distortions and kinetics in high entropy nitrides: an ab initio study — David Holec1, •Ganesh K. Nayak1, Andreas Kretschmer2, Paul H. Mayrhofer2, Marcus Hans3, and Jochen M. Schneider3 — 1Department of Materials Science, Montanuniversität Leoben, Leoben, Austria — 2Institute of Materials Science and Technology, TU Wien, Vienna, Austria — 3Materials Chemistry, RWTH Aachen University, Aachen, Germany
High entropy alloys (HEAs) have triggered significant scientific interest due to their unusual structural stability combined with excellent mechanical and other functional properties. Recently, exploration of materials used as protective coatings has also entered this room by exploring high entropy borides, oxides, carbides, and nitrides. These chemically complex systems provide huge combinatorial space for tuning the composition, hence making the experimental exploration tedious. High-throughput simulations based on unbiased ab initio calculations provide an ideal tool to guide the experiments.
We will show that for high entropy nitrides (HENs), strain is equally important for the stabilization as entropy. Our predictions were validated by experimental investigations on the thermal stability of selected HEN coatings. The predicted structures are further characterized in terms of their local distortions, one of the core effects of HEAs. Another core effect is sluggish bulk diffusion. Therefore, in the second part of the talk, we will explore correlations between migration barriers for bulk diffusion, local chemical compositions, and local distortions.