The susceptibility of high-strength aluminium alloys to intercrystalline corrosion still represents a great challenge in the development of these classes of materials. Intergranular corrosion; a form of corrosion in which the grain boundaries are preferentially dissolved and, owing to its deep penetration, can represent considerable safety risks, is considered as a potential initiator and promoter of stress corrosion cracking. On superposing the corrosive attack with mechanical stresses, SCC can lead to catastrophic component failure in high-strength aluminium alloys - in particular in Al-Zn-Mg-(Cu) alloys.
In the KKS (department for Corrosion and Corrosion Protection), intergranular corrosion and SCC are primarily investigated on precipitation-hardened wrought alloys and the corrosion mechanisms are correlated with the microstructural attributes. The grain boundaries and matrix precipitates, the dislocation density and structure, texture, stress state and other material parameters which are specifically set by means of forming and manufacturing processes as well as by heat treatment are the focus of the investigations.