Atomistic-continuum modeling of dislocation interaction with Y2O3 particles in iron

Abstract Oxide dispersion strengthened (ODS) steels are promising candidates for applications in fusion and fission rectors. Y 2 O 3 particles dispersed in an iron matrix drastically improve the strength without adverse effects on ductility. We investigate here details of the dislocation core structure in Y 2 O 3 precipitates, and at the interface between the iron matrix and the Y 2 O 3 precipitate. We also simulate dislocation interaction with nano-size Y 2 O 3 precipitates. It is shown that the γ -surface energies on planes between oxygen atoms and metallic atoms are extremely high, and that dislocations in an iron matrix cannot penetrate into Y 2 O 3 particles. Three-dimensional parametric dislocation dynamics simulations of the interaction between an edge dislocation and an Y 2 O 3 particle are carried out. The results show that the critical resolved shear stress (CRSS) has a strong dependence on the lattice mismatch Y 2 O 3 particles and the iron matrix, and that it is lower than analytically calculated values of the Orowan stress.