2025/05/26 by Lukas Meier, Asif Iqbal Bhatti, Meier, Lukas +5
Materials Science · #Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Fusion materials and technologies #Hydrogen embrittlement and corrosion behaviors in metals #Materials Science (cond-mat.mtrl-sci) #Nuclear Materials and Properties
paper · pdf · doi:10.48550/arxiv.2505.20071
openalex publication_date 2025/05/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Hydrogen uptake into body-centered cubic (bcc) iron as a root cause for subsequent hydrogen embrittlement, is initiated at the surface. In this paper, we quantify how readily H diffuses from the surface into the bulk. We consider a set of low-index, vicinal and general Fe surfaces and treat H-permeation as a two-step process. First, density-functional calculations determine the adsorption energy of an isolated H atom at every crystallographically distinct surface site. Second, for each adsorption site we map the minimum-energy pathway that carries the atom beneath the surface and into the lattice. Across all ten orientations studied, a clear trend emerges: sites that bind hydrogen most weakly (highest adsorption energy) are the starting point of the lowest-barrier diffusion channels into the metal interior. Thus, the least-favorable adsorption pockets act as gateways for efficient subsurface penetration. These insights provide a practical design rule: suppressing or minimizing exposure of such high-energy adsorption motifs - through appropriate surface texturing or orientation control - should make bcc-iron components less susceptible to hydrogen uptake and the associated embrittlement.