A Survey of Sensitization in 5xxx Series Aluminum Alloys

Abstract

The 5xxx series (Al-Mg-based) aluminum alloys suffer from intergranular corrosion and intergranular stress corrosion cracking when the alloy has become “sensitized.” Sensitization refers to insidious precipitation of β phase (Mg2Al3), which is problematic when present at grain boundaries. The β phase is electrochemically active and may preferentially dissolve. This paper reviews the relevant works that have documented the degree of sensitization for various 5xxx series alloys, providing a holistic overview of the issue, along with attention to the bulk composition, heat treatment, and microstructure.