Simulating corrosion of Al2CuMg phase by measuring ionic currents, chloride concentration and pH

• Localized electrochemical techniques are applied to study the corrosion of Al2CuMg phase.
• Al2CuMg phase reveals high level of self-dissolution.
• The alkalization of S phase can lead to the trenching of Al matrix around it.

The coupling of pure Al, Cu and Mg wires and the coupling of Al2CuMg intermetallic rod and Al wire were used to study the corrosion process of Al2CuMg phase particles in 2024-T3 aluminium alloy, by means of scanning vibrating electrode technique (SVET) and scanning ion-selective electrode technique (SIET). The results show the preferential dissolution of Mg in the coupling of Al, Cu and Mg. Al2CuMg was found to show self-dissolution when coupled with Al, rather than anodic dissolution. According to the results, a mechanism of early corrosion of S phase in AA2024-T3 is proposed.