Regensburg 2022 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 20: Computational Materials Modelling: HEA, Alloys & Nanostructures
MM 20.3: Vortrag
Mittwoch, 7. September 2022, 10:45–11:00, H44
Phase Stability and Ordering in Ta-Mo-Cr-Ti-Al Refractory High Entropy Alloys — •Yilun Gong1, Alexander Shapeev2, Fritz Koermann1,3, and Joerg Neugebauer1 — 1Max-Planck-Institut für Eisenforschung GmbH, Germany — 2Skolkovo — 3Delft University of Technology, The Netherlands
Predictive capabilities of phase stability and ordering in multi-component systems are critical to designing better alloys. This is particularly important for properties which are difficult to be quantified by traditional experimental techniques.
In the present work, a class of body-centered-cubic (bcc) refractory high entropy alloys was studied. In contrast to its superior high-temperature behaviour, it shows less-satisfying ductility below 600 ∘C. As origin of the poor mechanical performance long-range B2-ordering at low temperatures has been proposed but is still controversially discussed due to contradicting experimental findings. To predict and to quantify the temperature-dependent stable structure, we employed on-lattice machine-learning interatomic potentials (namely low-rank potentials). This type of potentials is capable of accurately describing chemical interactions in multi-component systems used in subsequent Monte Carlo simulations. Systematic studies of training qualities, statistical uncertainties and impact of local lattice distortions were conducted. Computed ordering sequence, site occupancies, short-range order parameters and alloying with interstitial O will be discussed.