Atomistic simulation of phosphorus segregation to Sigma 3 (111) symmetrical tilt grain boundary in alpha-iron

K Ebihara and T Suzudo, MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING, 26, 065005 (2018).

DOI: 10.1088/1361-651X/aace6a

Irradiation-induced grain boundary (GB) phosphorus segregation is an important factor for estimating the embrittlement of nuclear reactor pressure vessel steels, but the physical process of phosphorus migration to grain boundaries is still unclear. We numerically studied phosphorus migration toward a Sigma 3(111) symmetrical tilt GB in alpha-iron using molecular dynamics. We found that, in the vicinity of the GB within similar to 1 nm distance, an iron-phosphorus mixed dumbbell and an octahedral interstitial phosphorus atom push a self-interstitial atom into the GB, and the phosphorus atom becomes a substitutional atom. A phosphorus-vacancy complex in the region also becomes dissociated, and the vacancy is absorbed in the GB without dragging phosphorus. The results claim that a novel view of the segregation process is required.

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