Effects of Solution Treatment on Corrosion Properties of Mg–6 mass%Al–1 mass%Zn–2 mass%Ca (AZX612) and Mg–6 mass%Al–1 mass%Zn (AZ61) Alloys

Abstract

The effects of solution treatment on the corrosion properties of Mg–6 mass%Al–1 mass%Zn–2 mass%Ca (AZX612) alloy were investigated, and the results were compared with those for Mg–6 mass%Al–1 mass%Zn (AZ61) alloy. Solution treatment at 693 K for 48 h significantly reduced the corrosion rates of both AZX612 and AZ61 alloys in 5 mass% NaCl solution. After solution treatment, not only intermetallic phases but also the Al-rich α phase around intermetallic phases reduced or dissolved in both alloys. The microstructural evolution induced by solution treatment may inhibit galvanic corrosion and pit-like corrosion, leading to improvement in the corrosion resistance of AZX612 and AZ61 alloys.