MECHANICAL PROPERTIES AND TOPOLOGICAL CHANGES IN A Fe-CRYSTAL WITH FIXED AND MIGRATING H-ATOM: A NUMERICAL STUDY

摘要

A numerical study, within the framework of molecular statics, is conducted to assess the effect of a fixed and migrating hydrogen atom on the stress-strain data and the topological changes taking place in a 3D BCC α-iron crystal subjected to a tensile elongation. A pair-wise Morse potential is used to describe the interatomic forces. The results for a crystal with 2324 iron atoms show that the presence of a hydrogen atom, either migrating or fixed, produces relatively small effect on the stress-strain data within the elastic and some plastic range of loading. However, the topological changes, represented by the changes in the nearest neighbors for each atom within the cut-off distance after each displacement increment, are substantially different. Similarly, a comparison of the changes in the atomic potential energies when the sudden drop in stresses takes place shows differences between the two cases.