Microstructure characterization in a sensitized Al–Mg–Mn–Zn alloy

Abstract

Abstract Alloying elements, present in the aluminum solid solution or the precipitates, influence the corrosion resistance of Al–Mg–Mn–Zn alloys. In this study, sensitizing treatment was applied to an Al–Mg–Mn–Zn alloy to modify the precipitation at the grain boundaries or in the grains. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) were used to characterize various second‐phase particles and determine their orientation relationship with the Al matrix. After sensitizing treatment, τ‐phase (Mg 32 (Al, Zn) 49 ) is observed to precipitate along the grain boundaries in a coarser size, producing a discontinuous grain boundary precipitate structure. In addition, Mn‐rich particles are found to form with various shapes, such as global, plate and rhombus.