An atomistic study on the HELP mechanism of hydrogen embrittlement in pure metal Fe

Hasan M. S., Kapci M. F., Bal B., Koyama M., Bayat H., Xu W.

International Journal of Hydrogen Energy, cilt.57, ss.60-68, 2024 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 57
  • Basım Tarihi: 2024
  • Doi Numarası: 10.1016/j.ijhydene.2023.12.274
  • Dergi Adı: International Journal of Hydrogen Energy
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Artic & Antarctic Regions, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, Environment Index, INSPEC
  • Sayfa Sayıları: ss.60-68
  • Anahtar Kelimeler: Atomistic modeling, HELP mechanism, Hydrogen, Hydrogen embrittlement, Iron
  • Abdullah Gül Üniversitesi Adresli: Evet

Özet

The Hydrogen Enhanced Localized Plasticity (HELP) mechanism is one of the most important theories explaining Hydrogen Embrittlement in metallic materials. While much research has focused on hydrogen's impact on dislocation core structure and dislocation mobility, its effect on local dislocation density and plasticity remains less explored. This study examines both aspects using two distinct atomistic simulations: one for a single edge dislocation under shear and another for a bulk model under cyclic loading, both across varying hydrogen concentrations. We find that hydrogen stabilizes the edge dislocation and exhibits a dual impact on dislocation mobility. Specifically, mobility increases below a shear load of 900 MPa but progressively decreases above this threshold. Furthermore, dislocation accumulation is notably suppressed at around 1 % hydrogen concentration. These findings offer key insights for future research on Hydrogen Embrittlement, particularly in fatigue scenarios.