The performance of additively manufactured CuNi alloys with respect to resistance to various forms of corrosion damage is of great interest. Assessment of that performance also requires an understanding of the interconnections between microstructure, AM processing parameters, minor alloying elements and corrosion performance. A gap exists regarding understanding of how laser powder bed fusion (LPBF) CuNi performs in these regards relative to either wrought or cast legacy materials of the same nominal composition. Filling these gaps is a critical need for successful implementation of LPBF AM to utilize CuNi alloys in marine applications. This work is focused on evaluation of AM Cu30Ni alloy in comparison to wrought and cast alloys when assessed with respect to crevice corrosion behavior in 0.6M NaCl as well as ASTM D1141-98 simulated seawater (ASW). Different types of crevice formers (i.e., metal to metal, inert crevice former) were employed to understand the initiation sites, propagation and crevice dealloying mechanisms. The results indicated development of macro crevices inside and outside the crevice former; more crevice corrosion sites were observed for Cu30Ni immersed in naturally aerated ASW vs 0.6 NaCl. Fewer crevices were found for AM materials (when assessing average depth, max depth, crevice area) in comparison to both the cast and wrought conditions. Both Ni and Cu dealloying were observed and varied under relatively similar exposure conditions. Diagnostic H-cell experiments were performed in order to further understand crevice corrosion mechanisms.
