Abstract
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.
Highlights
IntroductionWith the development of light-weight automobiles in recent years, aluminum alloys (especially 6000-series aluminum alloys) have become widely used to produce automobile body sheets due to their good formability, corrosion resistance and baking hardening [1]
With the development of light-weight automobiles in recent years, aluminum alloys have become widely used to produce automobile body sheets due to their good formability, corrosion resistance and baking hardening [1]
The initial Kinetic Monte Carlo (KMC) configuration is usually a single-phase structure obtained by quenching, so the initial model with 25 × 25 × 25 super-cell was established according to the composition and the vacancy concentration CV of the alloy quenched from 803 K to room temperature, and CV was calculated by Equation (1) [18]: CV
Summary
With the development of light-weight automobiles in recent years, aluminum alloys (especially 6000-series aluminum alloys) have become widely used to produce automobile body sheets due to their good formability, corrosion resistance and baking hardening [1]. The early aging in Al-Mg-SiCu alloys, which directly affects the mechanical properties of these alloys by forming a main strengthening β” phase, is associated with the aggregation of solute atoms (clusters) without structural changes [4]. Research on the aging behavior of clusters can provide ways for improving the properties of the alloy. Due to the rapid aging, low contrast of solute atoms and metastable clusters, the early aging behavior of the alloy has been a longstanding controversial issue [5,6]. The detection efficiency of atoms mainly depends on the advanced level of the APT instruments. The detection efficiency was usually 37% to 57%, recently, it has been increased to 80% for advanced instruments such as the CAMECA
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
