Molecular dynamics study of phosphorus migration in Σ5 grain boundary of α-iron

To understand the de-trapping from grain boundaries of phosphorus atoms that bring about grain boundary embrittlement in steels, we numerically simulated using molecular dynamics the migration of a P atom in the grain boundary region of a Σ5 symmetrical tilt grain boundary of α-iron where the structure is largely different from that of α-iron. The behavior of iron atoms in the grain boundary region was also analyzed. The results were compared with the case of Σ3 symmetrical tilt grain boundaries. As a result, we found that the aspect of P atom migration and the behavior of iron atoms were significantly different between the two grain boundary cases. (author)