Interaction between vacancies and the α-Fe/Y2O3 interface: A first-principles study.

Oxide dispersion strengthened (ODS) ferritic steels are perceived as the most promising structural materials for advanced fission- and future fusion-reactor applications owing to their excellent irradiation resistance and high-temperature mechanical properties. To understand the role of interfaces under irradiation, the first-principles calculations have been performed to investigate geometric, energetic and electronic properties of the {1 0 0}<1 0 0>Fe//{1 0 0}<1 0 0>Y 2 O 3 interface as well as their interaction with radiation point defects. For O monovacancy in the Y 2 O 3 layer, its formation energy slightly increases when it approaches to interface. For Fe monovacancy, the vacancy formation energy decreases when the vacancy is close to the interface. For Fe–Fe divacancies, the formation energy of the first nearest neighbor (1NN) and 2NN Fe–Fe divacancies at the interface are −9.48 eV and −10.49 eV, while their binding energies are −2.46 eV and −1.45 eV, respectively. These results suggest that the α-Fe/Y 2 O 3 interface tends to attract vacancies in Fe matrix, yet prevents to form voids at the interface, which enhances radiation resistance of ODS steels. [ABSTRACT FROM AUTHOR]