A preliminary investigation of the corrosion and stress-corrosion susceptibility of thermomechanically processed high magnesium aluminum magnesium alloys

Abstract

The stress corrosion cracking susceptibility and general corrosion characteristics of four thermomechanically processed high-Magnesium, Aluminum-Magnesium alloys were evaluated and compared to those of 7076-T6. Results obtained from stress-corrosion testing and from tension testing after stress-corrosion exposure indicate that these 8-10% Mg alloys are less susceptible to stress corrosion cracking than 7076-T6. the addition of Cu or CU and Mn to a 10% Mg alloy raises strength, homogenizes the microstructure and reduces the tendency of such an alloy to exhibit intergranular cracking and exfoliation, especially in a sensitized condition. Results of accelerated general corrosion testing and marine exposure both indicate that binary 8% Mg and 10% Mg alloys are highly resistant to corrosion. Alloying with Cu or Cu and Mn accelerates weight loss, but to a lesser degree than observed for 7075-T6