Texture corrosion resistance of SDSS 2507/Inconel 625 GTA welds: a synergistic microstructural study

This study investigates the relationship between microstructure, crystallographic texture, and corrosion behavior in dissimilar gas tungsten arc (GTA) welded joints of super duplex stainless steel (sDSS2507) and Inconel 625 (IN625), employing ER2594 and ERNiCrMo-3 filler wires. Electron backscatter diffraction (EBSD) revealed dominant Brass {110}<112> and Goss {110}<100> textures in the base metals, while weld zones exhibited distinct features—ER2594 showed strong S {123}<412> and Brass textures, and ERNiCrMo-3 displayed {100}<uvw> fiber, Cube, and Rotated Cube components with a higher recrystallization fraction (up to 58 %). Texture intensity was reduced in IN625 HAZ compared to sDSS2507 HAZ, with γ-fiber and Cu components more prominent in the latter. Electrochemical analyses indicated that ERNiCrMo-3 welds exhibited the highest corrosion resistance, with a corrosion potential (Ecorr) of −124.7 mV and a significantly higher charge transfer resistance (R<inf>ct</inf>) of 21.85 kΩ cm2 compared to ER2594 (R<inf>ct</inf> = 7.42 kΩ cm2). Impedance modulus |Z| exceeded 105 Ω cm2 at low frequencies for ERNiCrMo-3, confirming superior barrier properties of the passive film. Bode plots revealed phase angles approaching 60°, indicative of stable capacitive behavior in both base metals and ERNiCrMo-3 welds. Corrosion mechanisms were strongly correlated with microstructural features. In ER2594 welds, localized corrosion initiated in the ferrite phase due to Cr<inf>2</inf>N and Laves phase precipitates, promoting chromium depletion and passive film breakdown. In contrast, ERNiCrMo-3 welds experienced pitting in the austenite matrix, where Nb–Mo-rich Laves phases coexisted with a more protective passive layer, resulting in reduced pitting susceptibility. These findings highlight the critical role of microstructure, texture, and passive film stability in determining corrosion behavior of dissimilar welds for marine applications. © 2025 Elsevier B.V., All rights reserved.