Al-Cu-Li-xMg合金时效初期微结构演变的Monte Carlo模拟

采用基于Multi-States Ising Model的Monte Carlo算法,模拟研究了Al-Cu-Li-xMg合金时效初期微观结构的演变过程,结果表明:时效早期,在Al-1.2Cu-5.7Li合金中微结构的主要形态是Li原子团簇、Li-Cu原子对和空位团簇,且空位团簇的出现多出现在Li原子团簇附近,形成共生形态;而Al-1.2Cu-5.7Li-xMg合金中,出现明显的Cu-Clusters,而Li原子的偏聚过程则受到抑制,且空位团簇的形态也发生了变化,多与Cu-Mg原子团簇形成共生形态;微量Mg的作用是通过Mg/Li原子间存在强烈的相互作用调整Li原子团簇的偏聚形态,导致大量被Li原子Clustering过程锁定的Cu原子和空位被置换出来,进而影响Li、Cu原子团簇的形态和空位的分布形态,并影响随后的析出相分布形态.

Monte Carlo simulation of microstructural evolution of Al-Cu-Li-xMg alloys during initial ageing stage

The Monte Carlo Method,which based on the Multi-States Ising Model,was applied to simulate the microstructural evolution of Al-Cu-Li-xMg alloys during the initial ageing stage.The simulation results show that: there are Li-clusters,Li-Cu co-clusters and vacancy-clusters in Al-Cu-Li alloy during the initial ageing stage,and Li clusters exhibit a tendency to co-existed with vacancy clusters;with small addition of Mg,Cu clusters are provoked,while the clustering of Li atoms is restrained,the vacancy clusters have a tendency to co-existed with Cu-Mg co-clusters.Small addition of Mg has strongly effect on the morphology of Li clusters,which can release Cu atoms and vacancies from the locking-state by Li clusters.Therefore,the morphology of precipitates can be affected by the addition of Mg subsequently.