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MM: Fachverband Metall- und Materialphysik

MM 45: Mechanical Properties and Alloy Design: e.g. Light-Weight, High-Temperature, Multicomponent Materials IV

MM 45.4: Vortrag

Mittwoch, 20. März 2024, 16:30–16:45, C 230

Parameterising dislocation dynamics in Ni-based superalloys from atomistic simulations — •Geraldine Anis, Thomas Hudson, and Peter Brommer — University of Warwick, Coventry CV4 7AL, UK

Ni-based superalloys are important materials for high temperature applications. Nanoscale precipitates in their microstructure hinder dislocation motion, which results in an extraordinary strengthening effect at elevated temperatures. In the present work, we parameterise the motion of edge dislocations in pure face-centred cubic (FCC) Ni, which we use to represent an idealized γ phase in Ni-based superalloys. Molecular dynamics (MD) simulations with classical effective potentials were used to obtain edge dislocation trajectories, and the parameters of equations of motion were then fitted using Differential Evolution Monte Carlo (DE-MC) within a Bayesian framework. The reduced model accounts for dislocation-dislocation and dislocation-precipitate interactions, and the fitting procedure yields physically meaningful parameters. Using DE-MC sampling makes it possible to obtain parameter distributions and propagate uncertainties through the model, quantifying the uncertainty in its predictions: the dislocation positions and velocities. This work serves as a first step towards building a more comprehensive surrogate model that can describe the deformation behaviour of Ni-based superalloys, where the parameterisation approach employed here can offer a quantitative measure of the effect of precipitates on dislocation dynamics in these materials.

Keywords: Dislocations; Molecular dynamics; Ni-based superalloys; Surrogate modelling; Uncertainty quantification