Al-Zn-Mg-(Sc)-(Zr)合金时效初期微结构演化的Monte Carlo模拟

Monte Carlo simulation of the microstructure evolution of Al-Zn-Mg-(Sc)-(Zr) alloys during the initial aging stage

采用Monte Carlo模拟方法研究了微量Sc、Zr对Al-2.1Zn-1.4Mg合金时效初期微结构演变的影响。结果表明:Al-2.1Zn-1.4Mg合金时效初期出现了Zn/Mg原子短程有序排布的共同团簇。由于"Sc/空位"机制,添加微量Sc后抑制了Al-2.1Zn-1.4Mg合金时效初期Zn/Mg共同团簇的偏聚,而微量Zr对时效初期Zn/Mg共同团簇的影响并不明显。微量Sc的添加使Al-2.1Zn-1.4Mg合金大量空位被Sc捕捉,形成Sc/空位团簇,剩余的空位与Zr原子和Mg原子结合,而Zn原子一般不容易被空位捕捉。Mg原子容易向Sc/空位团簇偏聚,Zn原子次之,Zr原子向Sc/空位团簇聚集的可能性较小。

The Monte Carlo simulation method were applied to study the effect of Sc and Zr on the initial aging microstruc-ture 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 va-cancies.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.