Stress Corrosion Cracking Susceptibility of Additively Manufactured Aluminum Alloy 7050 Produced by Selective Laser Melting in Chloride Environments

Additively manufactured, high-strength aluminum alloy 7050 (Al-Zn-Mg-Cu) produced by selective laser melting (SLM) was evaluated for stress corrosion cracking (SCC) susceptibility in chloride-containing environments relative to 7050-T7451 wrought plate. Constant extension rate tests and constant strain tests were conducted in 3.5% sodium chloride (NaCl) solutions. Test coupons were characterized for evidence of SCC following the test. The effects of chloride concentration and the presence of an oxidizer, i.e., hydrogen peroxide, on SCC and corrosion susceptibility were also studied. Results of the experiments implied that the 7xxx-series SLM alloy generally showed similar susceptibility to the 7050-T7451 plate with limited SCC initiation in the chloride environments. The presence of hydrogen peroxide changed the corrosion mode to intergranular corrosion and pitting.

Automated summary

The study found that additively manufactured, high-strength aluminum alloy 7050 produced by selective laser melting has similar stress corrosion cracking susceptibility as wrought plate 7050 in chloride environments, and the presence of an oxidizer can change the corrosion mode to intergranular corrosion and pitting.