The long-term corrosion resistance of commercially pure aluminum (AA1050) processed by equal channel angular pressing (ECAP) was evaluated in a saline environment. The study compared the microstructure and corrosion behavior of ECAP-processed samples in route A with 1X, 4X, and 8X passes to an annealed sample using a 3.5% NaCl solution. Characterization techniques, including optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), and electrochemical impedance spectroscopy (EIS), were employed. Results indicate that ECAP processing enhances the passive corrosion resistance compared to the undeformed sample. However, the improvement in corrosion resistance did not consistently increase with the number of ECAP passes. Factors such as the distribution of high- and low-angle grain boundaries, dislocation density, and fragmentation and redistribution of coarse dispersoid particles play a significant role in the corrosion behavior post-ECAP. Additionally, findings suggest that long-term immersion tests are required to obtain a more reliable electrochemical response.

The aim of this study concerns the effect of multi-pass shielded metal arc welding (SMAW) on the corrosion behavior of CW6MC cast nickel alloy. Using optical and SEM techniques the welded joint is analyzed. Vickers microhardness mapping and potentiodynamic polarization in NaCl and H₂SO₄ solutions are also evaluated. Both the Laves phase and NbC-type carbides are identified in the base metal (BM) and weld metal (WM) regions. The main microstructural difference observed between these regions is the morphology aspect and fineness of the dendritic arrays. The welding process promotes the finer columnar grains formation with refined intermetallic particles in the WM than equiaxed grains of the BM, which in turn results in higher microhardness values in the former region. However, no substantial changes were observed in the corrosion behavior between the BM and WM regions, considering both acid and saline media. Nevertheless, during the multi-pass SMAW process, some non-metallic micrometric inclusions (Mo and S-rich regions) can be constituted to occur in the WM region. This is associated with a significant drop in the corrosion performance of this region when the electrochemical tests are evaluated.