Simulation of clusters formation in Al-Cu based and Al-Zn based alloys

摘要

A Monte Carlo computer simulation is adopted to investigate the role of micro-alloying elements Mg and Ag in Al-Cu and Al-Zn alloys. Small amount additions of Mg to the Al-Cu alloy markedly retard the formation of Cu clusters due to the preferential trapping of free-vacancies available for Cu diffusion. On the other hand, additions of Mg to the Al-Zn alloy promote the formation of Zn clusters due to the preferential Mg-Zn interaction. As for the effect of Ag, it is found that, in both Al-Cu-Mg and Al-Zn-Mg alloys, Ag atoms are preferentially bounded to Mg-Cu-vacancy or Mg-Zn-vacancy complexes. However, in Al-Cu-Mg alloy Ag atoms interact with Mg, while in Al-Zn-Mg alloy they interact with both Mg and Zn.