Abstract
In this work, we apply atomistic simulations to consider hydrogen behavior in Fe in presence of the given lattice distortions, namely, crystal defects or lattice expansion/compression due to applied stresses. Simulations are based on new interatomic potential developed by the authors of the current work. Firstly, we consider the segregation of hydrogen on typical defects of different complexity: from vacancies to grain boundaries (GBs). The reported values of segregation energies obtained for different types of grain boundaries generally agree with the existing DFT data. Moreover, performed atomistic simulations give information on several types of GBs, which, due to their complex structure and considerable model size, are usually inaccessible for ab initio modeling. High-temperature simulations of H diffusion in the presence of GBs also show that for bcc Fe hydrogen diffusion coefficient in the boundary is much lower than that in bulk. For bulk under the stress, we discuss variations in hydrogen migration barriers (at zero temperature) and compare them with the results of the finite-temperature hydrogen diffusion simulations. We see that while variations in the lattice parameter change hydrogen migration barrier, they show no significant impact on the finite-temperature hydrogen diffusion coefficients.