Microstructure and Properties of High-Entropy AlxCoCrFe2.7MoNi Alloy Coatings Prepared by Laser Cladding

High-entropy AlxCoCrFe2.7MoNi (x = 0, 0.5, 1.0, 1.5, 2.0) alloy coatings were prepared on pure iron by laser cladding. The effects of Al content on the microstructure, hardness, wear resistance and corrosion resistance of the coatings were studied. The results showed that the crystal phases of the AlxCoCrFe2.7MoNi coatings changed from Mo-rich BCC1 + FCC to (Al, Ni)-rich BCC2 + Mo-rich BCC1 when x increased from 0 to 0.5, and the phase changed to an (Al, Ni)-rich BCC2 + (Mo, Cr)-rich σ phase as x increased further. The hardness of the coatings increased as the Al content increased. The Al2.0CoCrFe2.7MoNi coating exhibit best wear resistance. Addition of Al increased the corrosion potential in a 3.5 wt.% NaCl solution, and the coating with x = 1.0 exhibited the highest corrosion resistance.