Role of the Sink Density in Non-Equilibrium Chemical Redistribution in Binary Alloys
Résumé
Non-equilibrium chemical redistribution in open systems submitted to external forces, such as particle irradiation, leads to changes in the structural properties of the material, potentially driving the system to failure. Such redistribution is controlled by the complex interplay between the production of point defects, the atomic transport and the sink character of the microstructure. In this studywe apply a recently developed kinetic Monte Carlo (KMC) algorithm with an underlying atomistic model for the Fe-Cr alloy to study the effect of perfect defect sinks on Cr concentration profiles, with a particular focus on the role of interface density. We observe that the amount of segregation decreases linearly with decreasing interface spacing. Within the framework of the thermodynamicsof irreversible processes, an analytical model is derived and assessed against the KMC simulations to elucidate the structure-property relationship of this system. Interestingly, in the kinetic regime where elimination of point defects at sinks is dominant, the solute segregation does not directly depend on the dose rate but only on the density of sinks. This model provides with a simple and quantitative tool for the design of microstructures that mitigate chemical redistribution and improve radiation tolerance.