Molecular dynamics simulation analysis of hydrogen adsorption

Abstract

The adsorption and dissolution behaviour of hydrogen on metal surfaces is a key fundamental scientific issue for understanding the mechanisms of hydrogen-induced damage and the hydrogen embrittlement sensitivity of materials. In this study, based on first-principles principles and utilising molecular dynamics simulations, we systematically investigated the adsorption and dissolution behaviour of hydrogen molecules on the surface of α-Fe. The Embedded Atomic Model (EAM) was employed to accurately describe the interactions between α-Fe and H atoms. By constructing a surface model incorporating a vacuum layer and periodic boundary conditions, the dissociation, adsorption and dissolution of hydrogen molecules into the subsurface layer on an iron surface were simulated under various operating conditions. The results indicate that, at a given temperature, the adsorption of hydrogen on the metal surface is positively correlated with pressure; when the pressure increases from 5 MPa to 50 MPa, the hydrogen adsorption on the metal surface increases by a factor of 1.3. This provides a theoretical basis for a deeper understanding of the initial processes of hydrogen-induced damage and for the design of hydrogen embrittlement-resistant materials.