ANNポテンシャルを用いたα鉄中における格子間原子の拡散挙動とその活性化エネルギに関する研究

抄録

Neutron irradiation enhances the formation of vacancies and Self Interstitial Atoms (SIAs), which cause the material embrittlement as a consequence of the interaction with dislocations. The vacancies and SIAs spontaneously form their clusters due to their self-diffusion. In this study, we calculated the activation energies and the minimum energy paths of five different diffusion mechanisms (Event 1 ~ 5) in α-iron by means of the Nudged Elastic Band (NEB) method with an Artificial Neural Network (ANN) interatomic potential. The result of the NEB analysis suggests that the activation energy of the Event 1 mechanism is the lowest and is 0.34 eV whereas an EAM potential gives the activation energy as 0.31 eV. The ANN potential can also reproduce well the activation energies and the minimum energy paths of the other mechanisms as well as the first principles calculations. The reaction pathway analysis also tells us that the Event 2 ~ 5 mechanisms can be reproduced by the multiple reptations of the Event 1 mechanism.