Study on the Structure and Corrosion Behavior of AlCrCuFe2NiMo0.2Nb0.2Tix High-Entropy Overlay Welding Alloys

Due to the revolutionary changes in composition, high-entropy alloys have excellent properties. In this work, AlCrCuFe₂NiMo_0.2Nb_0.2Ti_x high-entropy overlay welding alloys is prepared on the surface of carbon steel plate by gas metal arc welding. The influence of titanium content on the microstructure and corrosion resistance of alloys is studied. The results show that the phases of the alloys are mainly composed of BCC solid solution containing FeCr phase and a small amount of (Nb, Ti)C. With the continuous addition of Ti element, the self-corrosion current density of the polarization curve decreases, and the corrosion resistance of the alloys increases. In the low-frequency region of the impedance spectrum, there are inductive impedance components with a tendency toward pitting corrosion. The doping of Ti element can enhance the stability of the passivation film and reduce the dissolution rate of the passivation film. When Ti is added to 0.8 mol, the self-corrosion current density is 3.5758 × 10⁻⁵ mA/cm², the self-corrosion potential reaches −0.70773 V, and the R_pass is 7.34 Ω cm². The corrosion resistance of the passivation film is the largest, and the corrosion resistance of the high-entropy overlay welding alloy is the best.