Li, S.Z.S.Z.LiLi, Y.G.Y.G.LiLo, Y.C.Y.C.LoNeeraj, T.T.NeerajSrinivasan, R.R.SrinivasanDing, X.D.X.D.DingSun, J.J.SunQi, L.L.QiGumbsch, P.P.GumbschLi, J.J.Li2022-03-0518.05.20172015https://publica.fraunhofer.de/handle/publica/24218510.24406/publica-r-24218510.1016/j.ijplas.2015.05.017By 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 alpha-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) similar to 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.en620journal article