The objective of this project is to investigate the effect of alloy composition and metallurgical state on the environmentally assisted cracking (EAC) behaviour of 7xxx Al alloys. Material with systematically varying alloy chemistry and microstructures will first be lab cast. The thermomechanical processing of cast alloys will be modified. Large area EBSD scans and TEM will be used to characterize the microstructure. EAC performance will be investigated by 4‐pt bend testing in humid air conditions to quantify EAC initiation time and crack growth rates of the alloys produced, and post‐mortem 3D imaging of cracked samples. Furthermore, analysis of the fracture surfaces to characterize EAC initiation sites and microstructurally short‐crack propagation will be performed.