Effect of Ti Addition on the Microstructure and Corrosion Resistance of AlCrCuFeNiNb0.2 High-Entropy Alloy

With rapid developments in industry, the unique design of high-entropy alloys (HEAs) has become a research hotspot in the field of corrosion. In this work, AlCrCuFeNiNb0.2Tix HEAs were prepared through flux-cored wire and deposited on the surface of low-carbon steel by gas metal arc welding (GMAW). The effect of Ti on the phase structure and corrosion resistance of AlCrCuFeNiNb0.2Tix HEA surfacing layer is discussed in detail. The results demonstrate that the microstructure of the surfacing layer was mainly composed of BCC solid solution with Fe-Cr phase and FCC solid solution with tiny amounts of MC phase. The microstructure presents the typical dendritic (DR) and interdendritic (ID) structures. It indicates that the addition of Ti can significantly promote the corrosion resistance of the surfacing layer. The corrosion resistance effect is stronger than that of 304 stainless steel. With the continuous addition of Ti, the self-corrosion current density of polarization curve decreases, the capacitance impedance radius of electrochemical impedance spectroscopy (EIS) increases, and the corrosion resistance of the surfacing layer improves. In the low-frequency region of EIS, there is an inductance component with pitting tendency. When the addition was Ti0.8, the corresponding corrosion resistance value of the surfacing layer impedance was the smallest.