Mapping the chemistry within, and the strain around, Al-alloy precipitates at atomic resolution by multi-frame scanning transmission electron microscopy

Abstract

Al-Mg-Si(-Cu)alloys, used primarily in the transportation sector, are strengthened by nano-sized precipitate particles. There is a plethora of possible phases, depending onwhich elements are added to the alloy and how the material is heat treated.Here we present results fromthe S, β’’, β’Geand Q’ phases,which allformrod-shaped precipitate with typical dimensions 7x7x50 nm. These phases are meta-stable, which means that they cannot exist outside the Al matrix.