Highly efficient and transferable interatomic potentials for {\alpha}-iron and {\alpha}-iron/hydrogen binary systems using deep neural networks

TL;DR

This paper introduces a new deep neural network interatomic potential for { extalpha}-iron and hydrogen systems that is over 40 times faster than previous models, enabling large-scale simulations of hydrogen embrittlement effects.

Contribution

The authors developed a highly efficient and transferable neural network potential for iron-hydrogen systems, significantly reducing computational costs while maintaining accuracy.

Findings

Hydrogen promotes brittle cleavage at crack tips.

Hydrogen facilitates intergranular nanovoid nucleation.

The new potential enables large-scale atomic simulations.

Abstract

Artificial neural network potentials (NNPs) have emerged as effective tools for understanding atomic interactions at the atomic scale in various phenomena. Recently, we developed highly transferable NNPs for {\alpha}-iron and {\alpha}-iron/hydrogen binary systems (Physical Review Materials 5 (11), 113606, 2021). These potentials allowed us to investigate deformation and fracture in {\alpha}-iron under the influence of hydrogen. However, the computational cost of the NNP remains relatively high compared to empirical potentials, limiting their applicability in addressing practical issues related to hydrogen embrittlement. In this work, building upon our prior research on iron-hydrogen NNP, we developed a new NNP that not only maintains the excellent transferability but also significantly improves computational efficiency (more than 40 times faster). We applied this new NNP to study the impact of hydrogen on the cracking of iron and the deformation of polycrystalline iron. We employed large-scale through-thickness {110}<110> crack models and large-scale polycrystalline {\alpha}-iron models. The results clearly show that hydrogen atoms segregated at crack tips promote brittle-cleavage failure followed by crack growth. Additionally, hydrogen atoms at grain boundaries facilitate the nucleation of intergranular nanovoids and subsequent intergranular fracture. We anticipate that this high-efficiency NNP will serve as a valuable tool for gaining atomic-scale insights into hydrogen embrittlement.