Revealing foundations of the intergranular corrosion of 5XXX and 6XXX Al alloys

Here, the nature of intergranular corrosion features and mechanisms for commercial 5083-H111, 6082-T6 and 6005A-T6 Al alloys are investigated comprehensively, supporting foundations for their management and maintenances under environmental conditions. It is found that the localized corrosions including the pitting, intergranular corrosion (IGC), exfoliation together with their coupling effects tend to the follow the direction and the morphology of precipitations and the elongated rolling/extrusion directions, suggesting grain refinement would be an effective approach to enhance the strength and IGC resistance. The microstructure characterizations and orientation statistics reveal the indicators improving durability and damage tolerance properties in the development of advanced Al alloys.