Effect of Cerium on Precipitated Phase and Corrosion Resistance of 2101 Duplex Stainless Steel

2101 duplex stainless steel is widely used because of its good mechanical properties of ferrite and excellent corrosion resistance of austenite. Due to the special dual-phase structure in steel, it is easy to cause secondary phase precipitation during hot working and reduce the corrosion resistance of steel. The effect of rare earth Ce on precipitated phase and corrosion resistance of aged 2101 duplex stainless steel was studied by means of electron microscope, XRD phase analysis and electrochemical workstation. The results show that the type of inclusions in the steel gradually changes from Al₂O₃ to CeAlO₃, Ce₂O₂S, Ce₂O₃ and a small amount of CeS; Rare earth solution at grain boundaries can effectively inhibit the formation of secondary precipitates. Electrochemical impedance spectroscopy also shows that the addition of rare earth can improve the capacitive arc resistance and corrosion resistance of steel. Rare earth modifies the inclusions in steel, which passivates the metal anode and forms a dense passivation film, which further hinders the occurrence of pitting corrosion.