Modeling radiation-induced segregation in austenitic Fe–Cr–Ni alloys

Abstract

To better predict radiation-induced segregation (RIS) in austenitic Fe–Cr–Ni alloys, a model is developed which uses pair interaction energies, ordering energies and local atomic configuration to calculate diffusion parameters. The model allows a single set of input parameters to describe a range of bulk alloy compositions. Comparisons of RIS measurements in austenitic Fe–Cr–Ni alloys with calculations using an inverse Kirkendall model have shown that composition specific diffusion parameters must be used to accurately predict segregation behavior, thus limiting the model's predictive capability when no prior segregation measurements exist. This paper describes the improved model and compares model calculations to segregation data from seven alloys irradiated at temperatures between 200 and 600°C and to doses from 0.1 to 3.0 dpa. Results show that the dose, temperature and composition dependence of the measured segregation data can be modeled using a single set of input parameters with no error greater than 5 at.%, but usually less than 2 at.%.