Back (Al-Base)

EN AW-7075 | AlZn5,5MgCu1,5 Fatigue Corrosion Cracking

Numeric designationEN AW-7075
Chemical designationAlZn5,5MgCu1,5
StateFatigue Corrosion Cracking

The 7000 Al alloys are classified as prone to stress and fatigue corrosion cracking. To assist crack propagation by a corrosive attack, even water  traces in the oil are sufficient. The fatigue crack surface combines the typical feather-like patterns of stress corrosion cracking with fatigue striations; the small final overload fracture is ductile (dimple fracture). The cause of failure in this case was the notch effect of a sharp-angled edge where several cracks started under cyclic loading.