Improving the mechanical and wear properties of AZ91 magnesium alloy via laser cladded (AlCu)3.5CoCrNiSnx (x = 0 and 1) high entropy alloy coatings

(AlCu) 3.5 CoCrNiSn x (x = 0 and 1) high entropy alloy (HEA) coatings were prepared on AZ91 magnesium alloy substrate by laser cladding technology. Both the HEA coatings consisted of FCC phase and BCC phase. The addition of Sn could lead to an increase in the relative proportion of the BCC phase and the formation of coarse dendritic structure in the HEA coating. The average microhardness and average wear weight loss of the (AlCu) 3.5 CoCrNi coating (612.2 HV and 2.9 mg) and (AlCu) 3.5 CoCrNiSn coating (562.1 HV and 3.9 mg) were both higher and lower than those of the AZ91 substrate (70.5 HV and 5.5 mg), indicating that the prepared HEA coatings could significantly improve the properties of the substrate. The (AlCu) 3.5 CoCrNi coating showed better performance than the (AlCu) 3.5 CoCrNiSn coating due to the grain refinement effect. • (AlCu) 3.5 CoCrNiSn x (x = 0 and 1) HEA coatings were prepared on AZ91 magnesium alloy. • Good metallurgical bonding was obtained between the HEA coatings and the substrate. • The addition of Sn could lead to an increase in the proportion of BCC phase in the coating. • Both the prepared HEA coatings could significantly improve the surface properties of the substrate.