Demonstration of the Stress Corrosion Resistance of Precipitation-Hardenable 5XXX Series Alloy AA5180

Author(s):

Taylor W. Cain

Abstract:

C-ring stress corrosion testing was performed on precipitation-hardenable Al-Mg-Zn-Cu alloy 5180 with a low (≈0.1 wt%) and high (≈0.225 wt%) Cu concentration in accordance with MIL-DTL-46027M. Samples in the as-received F-temper and solution-treated, waterquenched, and peak-aged T6-temper were found to survive the 96-h minimum requirement specified in MIL-DTL-46027M due to their exceptional ductility (>17% elongation to failure). Samples in the T6 condition failed after 15 days while samples in the F-temper did not fail after 28 days of testing. The discrepancy between tempers was linked to increased susceptibility of the T6-temper to intergranular corrosion attack, whereas no deviation between Cu content was observed.