SKM 2023 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 40: Mechanical Properties and Allloy Design
MM 40.1: Vortrag
Donnerstag, 30. März 2023, 15:45–16:00, SCH A 251
First principles validation of barriers in Ni3Al — •Adam Fisher1, Thomas Hudson1, Huan Wu2, Tyler London2, and Peter Brommer1 — 1University of Warwick, Coventry, UK — 2TWI Ltd, Cambridge, UK
Precipitates in Nickel-based superalloys form during heat treatment on a time scale inaccessible to direct Molecular Dynamics simulation, but can be studied using kinetic Monte Carlo (KMC). This requires reliable values for the barrier energies separating distinct configurations over the trajectory of the system. In this study, we validate barriers found with the activation relaxation technique nouveau (ARTn) method in a Ni3Al using a published potential for the atomic interactions against first-principles methods. In a first step, we confirmed that the ARTn barrier energies agree with those determined with the nudged elastic band (NEB) method. As the number of atoms used in those calculations is too great for direct ab initio calculations, we then cut the cell size to 255 atoms, thus controlling finite size effects. We then use the plane-wave density functional theory (DFT) code CASTEP and its inbuilt NEB method in the smaller cells. This provides us with a continuous validation chain from first principles to large-scale KMC and allows us to quantify the errors incurred in simulations of precipitate formation and evolution.