Repository logo
 

Grand canonical approach to modeling hydrogen trapping at vacancies in α-Fe

Published version
Peer-reviewed

Type

Article

Change log

Authors

Davidson, ERM 
Finnis, MW 

Abstract

Vacancies in iron are hydrogen traps, important in the understanding of hydrogen embrittlement of steel. We present a grand canonical approach to computing the trap occupancy as a function of both temperature and hydrogen concentration from practically zero to super-saturation. Our method couples a purpose-made machine-learned H-Fe potential, which enables rapid sampling with near density functional theory accuracy, with a statistical mechanical calculation of the trap occu- pancy using the technique of nested sampling. In contrast to the conventional assumption (based on Oriani theory) that at industrially relevant hydrogen concentrations and ambient conditions vacancy traps are are fully occupied, we find that vacancy traps are less than fully occupied under these conditions, necessitating a reevaluation of how we think about “mobile hydrogen” in iron and steel.

Description

Keywords

40 Engineering, 4018 Nanotechnology

Journal Title

Physical Review Materials

Conference Name

Journal ISSN

2475-9953
2475-9953

Volume Title

4

Publisher

American Physical Society (APS)

Rights

All rights reserved
Sponsorship
Engineering and Physical Sciences Research Council (EP/L014742/1)