Effect of aging route on the precipitation behavior and thermal stability of Al-Cu-Mg-Ag alloy

In this study, the evolution of U plates during artificial aging and the effect of peak-aging treatment and over-aging treatment on the thermal stability of Al-Cu-Mg-Ag alloy were investigated by scanning electron microscopy (SEM) and transmission electron mi-croscopy (TEM). It was shown that the diameter distribution of U plates in the over-aged sample was narrower compared to the peak-aged one, which suppressed the Ostwald ripening in the over-aged sample. In addition, the U plates in the over-aged sample has a larger aspect ratio than that in the peak-aged sample, which makes it more likely for the soft impinge to inhibit the growth of the U plates. Quantitative analysis showed that after heat exposure, U plates in the over-aged sample contributed more to the yield strength compared to peak-aged sample. This study shows that better thermal stability can be obtained in exchange for a little loss of room temperature mechanical properties, improving the application potential of Al-Cu-Mg-Ag alloys.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

In this study, the evolution of U plates during artificial aging was investigated, and the effects of peak-aging and over-aging treatments on the thermal stability of Al-Cu-Mg-Ag alloy were analyzed. The results showed that the over-aged sample had a narrower diameter distribution of U plates, which suppressed Ostwald ripening. Additionally, the U plates in the over-aged sample had a larger aspect ratio, making them more susceptible to inhibition by soft impinge. Quantitative analysis revealed that the over-aged sample exhibited higher yield strength contributed by U plates compared to the peak-aged sample. This study demonstrates that improved thermal stability can be achieved at the expense of slight loss in room temperature mechanical properties, enhancing the application potential of Al-Cu-Mg-Ag alloys.