Synergy of Intragranular and Intergranular Precipitation Behaviors in the Al-Mg-Xsi-Cu-Zn Alloys with High Corrosion Resistance

Abstract

The intergranular corrosion (IGC) resistance of age-hardening Al-Mg-Si-Cu alloys is closely related to the precipitation behavior adjacent to grain boundaries. In this study, we proposed to regulate the interaction of solute atoms and solute partitioning of Zn-containing Al-Mg-Si-Cu alloys by introducing dislocations, which can synergistically decorate the intergranular and intragranular precipitation behavior. Consequently, the continuity grain boundary precipitates and width of solute-depleted precipitate-free zones are inhibited accompanied with high number density or coarse precipitate in the matrix. As a result, the IGC resistance is greatly improved without strength and ductility loss, and the related mechanism has been proposed.

Keywords: Al-Mg-Si-Cu-Zn alloy, Si content, dislocation, Intergranular corrosion, Precipitation behavior