Corrosion behaviour of AZ80 Mg/beryllium–bronze–alloy galvanic couples in typical marine environment

A high-strength AZ80 Mg alloy was prepared via multi-direction forge, thermal extrusion and peak-aged heat treatment. The corrosion behaviour of AZ80 Mg/beryllium–bronze–alloy galvanic couples in a typical marine environment was investigated. Beryllium–bronze alloy (QBe1.7 Cu) acted as cathode, accelerating the corrosion of AZ80 Mg alloy. With the increase in contact areas, the corrosion rates and galvanic effect also increased, and the galvanic potentials moved positively. However, with a prolonged exposure time, the galvanic potentials and current densities decreased. The corrosion products mainly consisted of MgCl2, Mg5(CO3)4(OH)2·5H2O and MgSO4·7H2O. According to the standard of galvanic corrosion sensitivity from the Air Force Materials Laboratory (AFML), AZ80 Mg alloy was not allowed to make contact with QBe1.7 Cu alloy without effective protection.