Atomistic Investigation of the Influence of Hydrogen on Mechanical Response during Nanoindentation in Pure Iron

The effects of hydrogen on the mechanical response of pure iron with randomly distributed hydrogen atoms under nanoindentation were systematically investigated by molecular dynamics simulations with the aim to further understand hydrogen embrittlement mechanism in the steels.The simulations results revealed that,for the three models with[001],[110]and[111]surface normal,hydrogen reduced the critical load of the pop-in event,promoted the dislocation slipping and reduced the plastic region size and dislocation density around the indenter compared to the hydrogen free model.Meanwhile,the different mechanical responses of the three models with different surface normal were further explained in the perspective of Schmid factor.