Molecular dynamics study on diffusion behavior of Li in α-Fe

Liquid lithium has been considered as a candidate material for several components of future fusion devices. Since the containment materials are usually ferrous alloys, molecular dynamics simulations were performed to study the diffusion behavior of lithium atoms in bcc iron lattices. The stable interstitial sites for lithium atoms and the diffusion mechanism, as well as the diffusion barrier, were computed by using nudged elastic band method. The influence of vacancies was analyzed. The results suggest a strong binding effect. Through abundant simulations, the interaction between lithium atoms inside iron lattices was investigated, which interprets the forming process of lithium clusters. The temperature effect on the diffusion behavior of lithium atoms was discussed for all the cases including in the system with pure iron atoms, vacancies and interstitial lithium atoms. In addition, the diffusion coefficient of Li atoms in bcc Fe crystal was evaluated and analyzed.