Hydrogen-related phenomena due to decreases in lattice defect energies- Molecular dynamics simulations using the embedded atom method potential with pseudo-hydrogen effects
R Matsumoto and S Seki and S Taketomi and N Miyazaki, COMPUTATIONAL MATERIALS SCIENCE, 92, 362-371 (2014).
Solute hydrogen atoms and lattice defects are known to have strong interactions that significantly weaken the strength of a material. Although molecular dynamics (MD) simulations can treat complicated interactions among various lattice defects, their timescales are insufficient for the treatment of hydrogen diffusion over long distances or cooperative motion of hydrogen atoms and lattice defects at room temperature. Here, we used an interatomic potential for body-centered- cubic iron (bcc Fe) including pseudo-hydrogen effects on the lattice defect energies to perform three kinds of MD simulations: crack growth, nanoindentation, and tensile loading of a polycrystalline nanorod. The simulations show that well-known hydrogen-related phenomena can occur depending on the boundary conditions and the initial conditions of the materials. Our analyses indicate that decreasing the lattice defect energies leads to typical deformation and fracture behaviors in a gaseous hydrogen environment and that these so-called defactant effects of hydrogen play a significant role in hydrogen embrittlement. (C) 2014 Elsevier B.V. All rights reserved.
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