FIRST-PRINCIPLES STUDY OF THE OCCUPANCY OF BORON AND THE INTERACTION WITH VACANCY IN GAMMA-IRON

摘要

The solution type of boron and the interaction between boron atoms and vacancies in gamma-iron is analyzed using density function theory. The computational results show that boron atoms prefer to occupy the octahedral sites. The formation energy of octahedral boron is smaller than that of substitutional boron in gamma-iron. At elevated temperatures, boron atoms may enter into substitutional site if one of the nearest-neighbor sites around boron atom is vacancy. The binding energy is about 0.36ev, 1.17ev for the substitutional boron-vacancy complex and octahedral boron-vacancy complex, respectively. The non-equilibrium segregation of boron in gamma-Fe is mainly contributed by the substitutional boron-vacancy complex.