Insight on Interfacial Microstructure and Corrosion Characteristics of Mg/Al Explosive Welded Composite Plates

Abstract

Interfacial corrosion performance is crucial to the reliability of Mg/Al explosively welded composite plates. Nevertheless, more understanding is required concerning such interfacial corrosion. In this work, a combination of numerical simulation and experimental investigation was used to clarify the microstructure evolutions of AZ80‐Mg alloy/1060‐Al explosively welded composite plate. The formation of interfacial wave structure and the thermodynamic state were insighted through numerical simulation, which further enhanced the correlation between the interfacial microstructural heterogeneities and the interfacial corrosion characteristics. Galvanic corrosion was produced by the significant potential difference between the AZ80‐Mg and 1060‐Al, with multiple micro‐galvanic couples in the vortex zone. The corrosion occurred near the interface and gradually advanced away from the interface. After 1 h, the composite plates exhibited severe corrosion with deep pits on the Mg side, while the Al side was less affected. Within the vortex, however, the Mg‐rich region underwent little corrosion, whereas the Al‐rich region underwent significant corrosion, attributed to the increase in pH value caused by the Mg corrosion.