Abstract
Stress corrosion cracking (SCC) in Cu-free Al-Zn-Mg (7xxx) aluminium alloys limits its
use in many applications. In this work, we study in detail the microstructure of a peak and slightly
overaged condition in an AA7003 alloy using transmission- and scanning electron microscopy in
order to provide a comprehensive understanding of the microstructural features related to SCC.
The SCC properties have been assessed using the double cantilever beam method and slow strain
rate tensile tests. Grain boundary particles, precipitate free zones, and matrix precipitates have
been studied. A difference in the SCC properties is established between the two ageing conditions.
The dominating difference is the size and orientation of the hardening phases. Possible explanations
correlating the microstructure and SCC properties are discussed.
use in many applications. In this work, we study in detail the microstructure of a peak and slightly
overaged condition in an AA7003 alloy using transmission- and scanning electron microscopy in
order to provide a comprehensive understanding of the microstructural features related to SCC.
The SCC properties have been assessed using the double cantilever beam method and slow strain
rate tensile tests. Grain boundary particles, precipitate free zones, and matrix precipitates have
been studied. A difference in the SCC properties is established between the two ageing conditions.
The dominating difference is the size and orientation of the hardening phases. Possible explanations
correlating the microstructure and SCC properties are discussed.