Classical Molecular Dynamics Simulation of the Interaction of Hydrogen with Defects in Tungsten

The interaction of interstitial hydrogen (H) with dislocations and point defects in tungsten (W) is studied via numerical simulation within the framework of classical molecular dynamics (MD). Two alternative models are considered to describe the interatomic interactions: the embedded-atom method (EAM) and the bond-saturation model (the bond-order potential (BOP)). The calculated results are compared with data obtained via ab initio quantum-mechanical simulation. The potential developed recently within the framework of the EAM model demonstrated better agreement with the ab initio results than the BOP one. Molecular- statics calculations showed that hydrogen atoms are attracted by the dislocation core in both cases of screw and edge dislocations. The classical MD simulation of hydrogen diffusion in the vicinity of the edge dislocation demonstrated one-dimensional migration along the dislocation line.