Microstructure and corrosion behavior of Al-Cu intermetallics in laminated sheets

Abstract

The corrosion resistance of Al-Cu laminated sheets is crucial for industrial applications in harsh environments. Understanding the microstructure–corrosion coupling and stability of Al–Cu intermetallic compounds (IMCs) is crucial for enhancing their durability. The microstructural evolution and corrosion behavior of Al–Cu IMCs were investigated via high-resolution transmission electron microscopy (HRTEM) under various annealing conditions. The interfacial structures were studied based on the corresponding crystallographic planes. Compared with Al, Al-Cu intermetallics demonstrate greater corrosion resistance, although they remain less resistant than Cu. Corrosion initiates on the Al, followed by galvanic crevice corrosion of the intermetallics and exfoliation. These findings elucidate the corrosion mechanisms of Al-Cu intermetallics and offer guidance for optimizing interface design to improve their durability in corrosive environments.