Molecular dynamics simulation of Surface-Adsorbed-Hydrogen-Induced Dislocation Motion in a thin film

R Matsumoto and S Taketomi, COMPUTATIONAL MATERIALS SCIENCE, 171, 109240 (2020).

DOI: 10.1016/j.commatsci.2019.109240

Elucidating the effects of hydrogen on dislocation activities is important for revealing hydrogen embrittlement mechanisms. In situ transmission electron microscopy observations have shown that dislocation motion is enhanced or activated when hydrogen gas is introduced into the sample chamber, supporting the hydrogen-enhanced localized-plasticity mechanism. However, adsorbed hydrogen atoms affect dislocation activities in thin films. Here we analyzed the effects of hydrogen and sample thickness on the motion of screw dislocations through molecular dynamics simulations. The surface effect becomes significant with decreasing sample thickness, and the change in surface energy upon hydrogen adsorption induces motion of screw dislocations in ultrathin films.

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