Hydrogen diffusion in magnesium using machine learning potentials: a comparative study

Author(s)
Andrea Angeletti, Luca Leoni, Dario Massa, Luca Pasquini, Stefanos Papanikolaou, Cesare Franchini
Abstract

Understanding and accurately predicting hydrogen diffusion in materials is challenging due to the complex interactions between hydrogen defects and the crystal lattice. These interactions span large length and time scales, making them difficult to address with standard ab-initio techniques. This work addresses this challenge by employing accelerated machine learning (ML) molecular dynamics simulations through active learning. We conduct a comparative study of different ML-based interatomic potential schemes, including VASP, MACE, and CHGNet, utilizing various training strategies such as on-the-fly learning, pre-trained universal models, and fine-tuning. By considering different temperatures and concentration regimes, we obtain hydrogen diffusion coefficients and activation energy values which align remarkably well with experimental results, underlining the efficacy and accuracy of ML-assisted methodologies in the context of diffusive dynamics. Particularly, our procedure significantly reduces the computational effort associated with traditional transition state calculations or ad-hoc designed interatomic potentials. The results highlight the limitations of pre-trained universal solutions for defective materials and how they can be improved by fine-tuning. Specifically, fine-tuning the models on a database produced during on-the-fly training of VASP ML force-field allows the retrieval of DFT-level accuracy at a fraction of the computational cost.

Organisation(s)
Computational Materials Physics
External organisation(s)
University of Bologna, National Centre for Nuclear Research (NCBJ)
Journal
npj Computational Materials
Volume
11
No. of pages
8
ISSN
2096-5001
DOI
https://doi.org/10.48550/arXiv.2407.21088
Publication date
03-2025
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics, 103006 Chemical physics, 103043 Computational physics
ASJC Scopus subject areas
Modelling and Simulation, General Materials Science, Mechanics of Materials, Computer Science Applications
Portal url
https://ucrisportal.univie.ac.at/en/publications/18ae2f4c-87dc-44bb-b141-0d8a0fe7483e