Influence of the microstructure on the corrosion behaviour of a shape memory Cu-Al-Be alloy in a marine environment

The influence of the microstructure on the corrosion behaviour of a shape memory Cu-11.40Al-0.55Be (wt.%) polycrystalline alloy in 3.5% NaCl has been studied by microscopical examinations, spectroscopical and X-ray diffraction measurements, and electrochemical tests. Chloride environment can produce a dealuminization attack, and the corrosion behaviour is affected by the alloy microstructural conditions. After long times of immersion, the single β phase microstructure suffers localized corrosion in some regions but dealuminization is generalized on the whole surface. However, in the (β + γ₂) microstructure, preferential dissolution of γ₂ dendritic precipitates occurs, which seems to protect β matrix from dealloying.