Radiation induced segregation in quaternary Fe-Ti-Y-O alloys

Radiation induced segregation of alloying elements in nanostructured ferritic alloys (NFAs), a material used for fuel cladding, results in embrittlement at grain boundaries, which comprises the lifetime of the material. This study models this segregation by the creation, migration, recombination, and annihilation of point defects by electron irradiation using rate theory. A progression was used in the development of the models from simplistic pure iron to binary Fe-Y to the complex Fe-Ti-Y-O. The rate theory equations break from previous ternary alloy models found in literature by modeling the movement of oxygen, an element preferentially found in the octahedral sites and travels by interstitial diffusion. The simulations from both models showed agreement with literature with enrichment of alloying elements Y, Ti, and O at grain boundaries. A validation method of the model based on thermal segregation is also described.