Aluminum-Zinc-Magnesium Stress Corrosion Cracking
Aluminum-zinc-magnesium stress corrosion cracking is corrosive deterioration of cracks under tensile stress in high-strength alloys, promoted by active grain boundary precipitates.
Physical-Chemical Mechanism of Action
Under tensile stress, active grain boundary precipitates in aluminum-zinc-magnesium alloys can react corrosively. These reactions release chemical compounds that further enlarge and damage the crack area.
Metallurgical Relevance & Welding Risks
This corrosion can lead to more crack-prone materials, especially when the alloy is high-strength. This increases the risk of crack propagation and reduces component life.
Workshop Practice & Action Instructions
When welding Al-Zn-Mg alloys, use filler materials with high thermal conductivity to speed up cooling. Ensure proper weld cooling and avoid overly slow cooling times that can lead to the formation of active grain boundary precipitates.