Simulations of hydrogen embrittlement in Ni-based super alloys

Hydrogen embrittlement (HE) is a major issue affecting the lifetime and operational safety of Ni-based superalloys especially at intermediate temperatures. We aim to use first-principles calculations at finite temperatures in combination with machine learning (ML) techniques to derive an accurate picture of HE in these alloys. The first-principles energies and forces will be used to train Moment Tensor Potentials (MTPs) – a recent and powerful type of machine learning potentials – which will be employed, e.g., in large scale Molecular Dynamics (MD) simulations of hydrogen diffusion in bulk Ni and Ni3Al. This interatomic potential will also allow for the determination of the temperature dependent antiphase boundary energy (APB energy) for 0 precipitates (i.e., Ni3Al) which is a measure for the ability of dislocations to enter and propagate in these precipitates. The resulting knowledge of this key quantity together with the availability of a very accurate machine trained interatomic potential will provide a fundamental basis for the future design of hydrogen-tolerant and creep resistant Ni-based superalloys.