Fabrication and friction properties of the AlFeCrCo medium-entropy alloy coatings on magnesium alloy

In this study, the AlFeCrCo medium-entropy alloy coating was first fabricated on a magnesium alloy using a resistance seam welding method. After welding, the AlFeCrCo medium entropy amorphous alloy powders were transformed into a body-centered cubic structure coating having an average thickness of 430 μm. The effect of instantaneous temperature on the formation ability of the coating was analyzed by theoretical calculations and experimental results. Based on the calculations, the instant Joule heating effect was only concentrated in the minute bonding area, and no direct or immediate increase in temperature occurred at the substrate. The experimental results demonstrated that the temperature gradient did not engender an obvious dilution of the matrix. The average microhardness of the coating (870 HV0.2) was approximately 12 times higher than that of the substrate. The wear performance was systematically evaluated in dry and 3.5 wt% NaCl solution conditions under different normal loads. Compared with the substrate and other high entropy alloy-related systems, the AlFeCrCo medium-entropy alloy coating exhibited good wear resistance. The wear resistance improved when the metal films and corrosive behavior were occurred in corrosive environments, which was anomalous to wear mechanism under dry conditions. [Display omitted] •The AlFeCrCo medium-entropy alloy coating was firstly fabricated on magnesium alloy.•After welding, the AlFeCrCo MEA amorphous powders were transformed into a BCC-structured coating.•The coating exhibited better wear resistance than the substrate and other HEA-related systems.