Effects of Sn Addition on Precipitation of Al-Zn-Mg Alloy at Early Stage of Natural Aging

Abstract

We investigated the effects of microalloying Sn addition on solute clustering in Al-Zn-Mg alloys during the early stages of natural aging. This study demonstrates that Sn retards the natural aging behavior by facilitating the formation of Mg-Sn clusters, which suppress the formation of Guinier-Preston zones (I) during the earliest aging stage. This is because Sn strongly binds with Mg-vacancy pairs to form Mg-Sn clusters due to their high binding energy.

Keywords: aluminum alloys, precipitation, natural aging, atom-probe tomography, density functional theory