The kinetics of clustering in Al–Mg–Si alloys studied by Monte Carlo simulation

Abstract

Abstract The kinetics of clustering in Al–Mg–Si alloy is studied by means of Kinetic Monte Carlo simulations. The simulations take into account the probability of vacancy jumping to nearest neighbour sites. This probability is calculated by considering both the activation energies for single vacancy migration and the difference of interaction energies before and after jumping. The simulations show that clustering in Al–Mg–Si is fast and takes place in three stages. In the initial stage, dimers, trimers and small co-clusters form. The number density of such clusters increases rapidly and solute atoms aggregate to those clusters until a maximum number density value is reached after 2 min. In the second stage, from 2 min to around 100 min, a decrease in the number density of clusters is accompanied by an increase in the fraction of solute contained in all the clusters. Finally, a further reduction in the cluster number density is observed, while the amount of solute atoms in the clusters remains constant. We discuss how robust the results are with respect to changes in the input parameters.