Ye Qilu, Wu Jianxin, Zhao Jiqing, Yang Gang, Yang Bin
Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083, China.
Institute for Special Steels, Central Iron and Steel Research Institute, Beijing 100081, China.
Materials (Basel). 2021 Aug 12;14(16):4523. doi: 10.3390/ma14164523.
The mechanism of the clustering in Al-Mg-Si-Cu alloys has been a long-standing controversial issue. Here, for the first time, the mechanism of the clustering in the alloy was investigated by a Kinetic Monte Carlo (KMC) approach. In addition, reversion aging (RA) was carried out to evaluate the simulation results. The results showed that many small-size clusters formed rapidly in the early stages of aging. With the prolongation of aging time, the clusters merged and grew. The small clusters formed at the beginning of aging in Al-Mg-Si-Cu alloy were caused by initial vacancies (quenching vacancies). The merging and decomposition of the clusters were mainly caused by the capturing of vacancies, and the clusters had a probability to decompose before reaching a stable size. After repeated merging and decomposition, the clusters reach stability. During RA, the complex interaction between the cluster merging and decomposition leaded to the partial irregular change of the hardness reduction and activation energy.
Al-Mg-Si-Cu合金中团簇形成的机制一直是一个长期存在争议的问题。在此，首次采用动力学蒙特卡罗（KMC）方法研究了该合金中团簇形成的机制。此外，还进行了回复时效（RA）以评估模拟结果。结果表明，在时效初期迅速形成了许多小尺寸团簇。随着时效时间的延长，团簇合并并长大。Al-Mg-Si-Cu合金时效初期形成的小团簇是由初始空位（淬火空位）引起的。团簇的合并和分解主要是由空位的捕获引起的，并且团簇在达到稳定尺寸之前有分解的可能性。经过反复的合并和分解后，团簇达到稳定状态。在回复时效过程中，团簇合并和分解之间的复杂相互作用导致硬度降低和激活能出现部分不规则变化。
