Molecular dynamics simulations of cascade damage near the Y ₂ Ti ₂ O ₇ nanocluster/ferrite interface in nanostructured ferritic alloys

Abstract

A comparative study of cascades in nanostructured ferritic alloys and pure Fe is performed to reveal the influence of Y 2 Ti 2 O 7 nanocluster on cascades by molecular dynamics simulations. The cascades with energies of primary knock-on atom (PKA) ranging from 0.5 keV to 4.0 keV and PKA's distances to the interface from 0 Å to 50 Å are simulated. It turns out that the Y 2 Ti 2 O 7 nanocluster can absorb the kinetic energy of cascade atoms, prevent the cascade from extending and reduce the defect production significantly when the cascades overlap with the nanocluster. When the cascade affects seriously the nanocluster, the weak sub-cascade collisions are rebounded by the nanocluster and thus leave more interstitials in the matrix. On the contrary, when the cascade contacts weakly the nanocluster, the interface can pin the arrived interstitials and this leaves more vacancies in the matrix. Moreover, the results indicate that the Y 2 Ti 2 O 7 nanocluster keeps stable upon the displacement cascade damage.