关键词: Monte Carlo模拟, Al-Zn-Mg合金, 微结构演化, 时效

Abstract:

The Monte Carlo simulation method were applied to study  the effect of Sc and Zr on the initial aging microstructure evolution of Al-2.1Zn-1.4Mg alloy. The simulation results showed that there were Zn／Mg short range orderings in Al-2.1Zn-1.4Mg alloy during the initial aging stage. Due to  the  ‘Sc／vacancy’ mechanism, the aggregation of Zn／Mg clusters was depressed during the initial aging by adding  Sc to Al-2.1Zn-1.4Mg alloy. Addition of Zr has little effect on the size of Zn／Mg co-clusters. The addition of Sc to Al-2.1Zn-1.4Mg alloy could  induce most vacancies combining to Sc forming Sc／vacancies clusters, the remaining vacancies combined with Zr and Mg, while Zn atoms are not easy to be captured by vacancies. Mg atoms  could easily aggregate to the ‘Sc／vacancy’ clusters and then follow Zn atoms, while Zr atoms were less likely to aggregate to these clusters.

Key words:  Monte Carlo simulation, Al-Zn-Mg alloys, microstructure evolution, aging