Monte carlo simulations of precipitation under irradiation

Abstract

Atomistic kinetic Monte Carlo (AKMC) is a powerful technique to study the microstructural and microchemical evolution of alloys controlled by diffusion processes. AKMC simulations are thus ideal tools to study precipitation, under irradiation and during thermal aging. In this chapter, we briefly present the method, underlining the different hypotheses usually made in the studies which have been done so far and the increasing contribution of density functional theory (DFT) calculations. We then proceed to present several simulations of the first stages of precipitation that can be quantitatively compared with experimental studies, in order to show the complexity introduced by the irradiation. We move to the mesoscale and introduce event kinetic Monte Carlo (EKMC) and object kinetic Monte Carlo (OKMC) methods which until now have mostly dealt with point defect cluster distributions in pure metals or “gray alloys” and were thus not really appropriate to study precipitation. However, they can be coupled with AKMC to speed up the calculations and recent developments take into account solute atoms more explicitly.We expose then recent advances that relieve some of the simplifying assumptions of standard AKMC models and conclude with a few challenging issues that we feel need to be addressed to predict correctly the behavior of alloys under irradiation but have been barely introduced in the models.