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Hydrogen-modified interaction between lattice dislocations and grain boundaries by atomistic modelling

Journal Article


Abstract


  • © 2020 Hydrogen Energy Publications LLC Dislocation plasticity in the vicinity of grain boundaries (GBs) plays a critical role in H-induced intergranular failure. Their interaction mechanisms under H environment, however, remain largely unexplored. Here, the underlying interaction of a screw dislocation with [11¯0] symmetric tilt GBs was studied by using molecular dynamics simulation, with special concerns on the role of solute H in it. Our results show several interaction mechanisms including dislocation dissociation, transmission, nucleation and reflection, depending on different glide planes and GB structures. The presence of H tends to transform these reactions into ones involving dislocation absorption due to H-hindered GB migration and H-enhanced localised plasticity. Furthermore, it is quantified that solute H leads to an increase in energy barrier for dislocation-grain-boundary interaction. After dislocation absorption, the GB segregated with H atoms is activated to a more disordered atomic structure, which can be correlated to the crack nucleation and hence the ultimate fracture. These findings advance a mechanistic understanding on H-induced plasticity-mediated intergranular failure.

Authors


  •   Li, Jiaqing (external author)
  •   Lu, Cheng
  •   Pei, Linqing (external author)
  •   Zhang, Che (external author)
  •   Wang, Rui (external author)

Publication Date


  • 2020

Citation


  • Li, J., Lu, C., Pei, L., Zhang, C. & Wang, R. (2020). Hydrogen-modified interaction between lattice dislocations and grain boundaries by atomistic modelling. International Journal of Hydrogen Energy,

Scopus Eid


  • 2-s2.0-85079374894

Place Of Publication


  • United Kingdom

Abstract


  • © 2020 Hydrogen Energy Publications LLC Dislocation plasticity in the vicinity of grain boundaries (GBs) plays a critical role in H-induced intergranular failure. Their interaction mechanisms under H environment, however, remain largely unexplored. Here, the underlying interaction of a screw dislocation with [11¯0] symmetric tilt GBs was studied by using molecular dynamics simulation, with special concerns on the role of solute H in it. Our results show several interaction mechanisms including dislocation dissociation, transmission, nucleation and reflection, depending on different glide planes and GB structures. The presence of H tends to transform these reactions into ones involving dislocation absorption due to H-hindered GB migration and H-enhanced localised plasticity. Furthermore, it is quantified that solute H leads to an increase in energy barrier for dislocation-grain-boundary interaction. After dislocation absorption, the GB segregated with H atoms is activated to a more disordered atomic structure, which can be correlated to the crack nucleation and hence the ultimate fracture. These findings advance a mechanistic understanding on H-induced plasticity-mediated intergranular failure.

Authors


  •   Li, Jiaqing (external author)
  •   Lu, Cheng
  •   Pei, Linqing (external author)
  •   Zhang, Che (external author)
  •   Wang, Rui (external author)

Publication Date


  • 2020

Citation


  • Li, J., Lu, C., Pei, L., Zhang, C. & Wang, R. (2020). Hydrogen-modified interaction between lattice dislocations and grain boundaries by atomistic modelling. International Journal of Hydrogen Energy,

Scopus Eid


  • 2-s2.0-85079374894

Place Of Publication


  • United Kingdom