The interaction of dislocations and hydrogen-vacancy complexes and its importance for deformation-induced proto nano-voids formation in α-Fe

Suzhi Li, Yonggang Li, Yu-Chieh Lo, Thirumalai Neeraj*, Rajagopalan Srinivasan, Xiangdong Ding, Jun Sun, Liang Qi, Peter Gumbsch, Ju Li

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

84 Scopus citations

Abstract

By using molecular dynamics and cluster dynamics simulations, we probed the role of hydrogen-vacancy complexes on nucleation and growth of proto nano-voids upon dislocation plasticity in α-Fe. Our atomistic simulations reveal that, unlike a lattice vacancy, a hydrogen-vacancy complex is not absorbed by dislocations sweeping through the lattice. Additionally, this complex has lower lattice diffusivity; therefore, it has a lower probability of encountering and being absorbed by various lattice sinks. Hence, it can exist metastably for a rather long time. Our large-scale molecular dynamics simulations show that when metals undergo plastic deformation in the presence of hydrogen at low homologous temperatures, the mechanically driven out-of-equilibrium dislocation processes can produce extremely high concentrations of hydrogen-vacancy complex (10-5 ∼ 10-3). Under such high concentrations, these complexes prefer to grow by absorbing additional vacancies and act as the embryos for the formation of proto nano-voids. The current work provides one possible route for the experimentally observed nano-void formation in hydrogen embrittlement of steels and bridges atomic-scale events and damage with macroscopic failure.

Original languageEnglish
Article number1925
Pages (from-to)175-191
Number of pages17
JournalInternational Journal of Plasticity
Volume74
DOIs
StatePublished - 1 Nov 2015

Keywords

  • Corrosion and embrittlement
  • Crystal plasticity
  • Fracture mechanisms
  • Numerical algorithms

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