微结构演变的计算机模拟
(中南大学 材料科学与工程学院， 长沙 410083)
摘 要: 采用Monte-Carlo方法模拟了时效初期Al-4.0Cu-0.3Mg-(0.4Ag)-(0.2Sc)合金的原子分布。研究结果表明： 在时效过程中含微量钪的Al-Cu-Mg合金中镁原子逐步向钪原子周围偏聚，而铜原子并没有向钪原子周围聚集的倾向， 时效初期出现了大量的Mg/Sc原子团簇及Mg/Sc/空位复合体； 微量钪的存在促进了镁原子团簇化，但抑制了铜原子的团簇化； 而含微量银的合金中镁原子向银原子周围偏聚的倾向比铜原子大得多， 时效初期出现了大量的Ag/Mg原子团； “Sc/空位”机制是微量钪影响Al-Cu-Mg合金时效初期原子分布与形态的关键所在。
关键字: Monte-Carlo 方法； 铝合金； 时效
microalloyed Al-4.0Cu-0.3Mg alloys
（ School of Materials Science and Engineering,
Central South University, Changsha 410083, China）
Abstract: The Monte-Carlo method was applied to simulate the distribution of solutes in the microalloyed Al-4.0Cu-0.3Mg alloys during the initial ageing stage. The simulation results show that the distribution and morphology of the clusters have been modified by trace element additions, and it is found that one of the key factors governing this effect is Sc/vacancy mechanism. Small additions of Sc to Al-Cu-Mg alloys exhibit a strong tendency to form Mg/Sc cluster and Mg/Sc/vacancy complexes in the atom configurations. The presence of Sc stimulates the clustering of Mg, while depresses the clustering of Cu. A small addition of Ag to Al-Cu-Mg alloys exhibits a strong tendency to form Ag/Mg cluster.
Key words: Monte-Carlo method; aluminium alloys; ageing
