Aluminum Stress Corrosion Cracking
Aluminum stress corrosion cracking is a sudden deterioration of aluminum alloys under the influence of tensile stresses and corrosive environment. The material dissolves at the cracks, leading to sudden failure.
Physicochemical Mechanism of Action
Aluminum stress corrosion cracking occurs due to the attraction of chloride ions (Cl-) and other corrosive ions to stress areas in aluminum alloys. These ions react with the aluminum, which dissolves there, leading to a molten film. This film protects the aluminum core from further corrosion until it is destroyed again by mechanical stress or chemical reactions.
Metallurgical Relevance & Risks in Welding
This form of corrosion is especially dangerous because it can occur suddenly and without warning signs. It leads to sudden material failure, which can cause serious damage or even accidents in the workshop. Stresses can arise from mechanical stress, incomplete cooling, or faulty welding.
Workshop Practice & Action Guidelines
To avoid aluminum stress corrosion cracking, it is crucial to use correct welding procedures and materials. This includes thorough cleaning of the material before welding, using corrosion-resistant filler metal, and adhering to proper cooling times. Be especially cautious with aluminum alloys with high chloride content and take special corrosion prevention measures if necessary.