Fabrication and Characterization of AlxFeMnNiCrCu0.5(x = 0.0; 0.5; 1.0) High-Entropy Alloy Coatings by Laser Cladding

In this study, Co-free AlxFeMnNiCrCu0.5 high-entropy alloy (HEA) coatings were prepared on the AISI 1045 steel substrate by laser cladding. The macrograph, phase, microstructure characteristics, microhardness, and corrosion resistance of HEA coatings were investigated. The results show that a defect-free HEA coating with a strong metallurgical bonding with the substrate could be obtained under the optimized processing parameters. With the increase in aluminum addition, the coating phase transformed from the single FCC phase of FeMnNiCrCu0.5 coating to FCC/BCC duplex phases of Al0.5FeMnNiCrCu0.5 coating and then to a single BCC phase of Al1.0FeMnNiCrCu0.5 coating. The microhardness of HEA coatings increases with increasing Al content, and the maximum microhardness of Al1.0FeMnNiCrCu0.5 HEA coating reached up to 541 HV0.2, which was about three times higher than that of 1045 steel. Potentiodynamic polarization and electrochemical impedance spectroscopy test confirmed that in 0.5 mol/L H2SO4 solutions, the AlxFeMnNiCrCu0.5 HEA coatings exhibited a good corrosion resistance, and the corrosion resistance of FeMnNiCrCu0.5 HEA coating was the best among them.