The Effect of a Sc : Zr Ratio on the Corrosion Resistance of Cast Al–Mg Alloys

The results of the studies of the corrosion resistance of Al–Mg alloys with different contents of magnesium and different ratios of scandium and zirconium (Sc : Zr) have been presented. The alloys have been obtained using induction casting. The effect of the annealing temperature on the microhardness and specific electrical resistivity of cast Al–Mg–Sc–Zr alloys has been studied. Electrochemical corrosion tests were performed in an environment simulating intergranular corrosion in aluminum alloys. It has been shown that an increase in the content of magnesium results in an increase in the corrosion current, and a decrease in the content of scandium (under the condition of Sc + Zr = const) results in a decrease in the rate of intergranular corrosion. It has been established that the dependence of the corrosion current density on the annealing temperature of Al–Mg–Sc–Zr alloys with an increased Sc : Zr ratio exhibits a non-monotonic pattern with a maximum.