Effect of Friction Stir Welding Parameters on Microstructure and Corrosion Behavior of 2101 Duplex Stainless Steel in Simulated Body Fluid

This study examines the effect of various parameters of friction stir welding (FSW) on 2101 lean duplex stainless steel (LDSS) microstructural features, and corrosion properties in simulated body fluid (SBF) for possible biomedical applications. 2101 LDSS FSW joints were characterized using scanning electron microscopy (SEM). X-ray diffraction (XRD) was used to investigate changes to crystalline phases. The Corrosion behavior was evaluated in Ringer solution by Tafel potentiodynamic polarization (PDP), as well as by cyclic polarization (CP) and electrochemical impedance spectroscopy (EIS) tests. The microstructural observations show that the heat input was not high enough to form a heat affected zone (HAZ), with three separate zones identified around the weld zone. The three identified zones are: stir zone (SZ), thermomechanical affected zone (TMAZ) and base metal (BM). A positive linear correlation between the rotational speed and the corrosion resistance were detected, with the behavior related to the more balanced microstructure or to grain refinement.