Microstructure and Properties of AlCo_xCrFeNiCu High-Entropy Alloy Coating Synthesized by Cold Spraying Assisted Induction Remelting

High-entropy alloy coatings have a very wide range of industrial applications due to their outstanding mechanical properties and good wear resistance. High-entropy alloy coatings of AlCoxCrFeNiCu (x = 0, 0.5, 1.0, 1.5, 2.0, mole fraction) on 45 steel substrates were successfully produced by cold spraying assisted induction remelting approach. The effect of Co content on the phase and microstructure of cold spraying-assisted high-entropy alloy coating was investigated. The findings reveal that the AlCoxCrFeNiCu high-entropy alloy coating produced using low-pressure cold spraying assisted induction remelting technique comprises of fcc + bcc two-phase mixed structure, with an equiaxed dendrite + interdendritic structure, with the dendrite being bcc and the interdendritic structure being fcc. The lattice distortion state of AlCoxCrFeNiCu high-entropy alloy coating changes as the Co element changes; when x = 1.0, the lattice strain of AlCo1CrFeNiCu high-entropy alloy coating is the largest. Increases in Co content promote an increase in dendrite number in AlCoxCrFeNiCu high-entropy alloy coatings, as well as dendrite. The EDS analysis demonstrated that Fe, Cr, Co, and Ni were enriched in the dendrite, Cu was enriched in the interdendrite, and Al was evenly distributed throughout the coating. With an increase in Co content, the hardness of AlCoxCrFeNiCu high-entropy alloy coating increases first and then decreases. When x = 1.0, the hardness of the AlCo1CrFeNiCu high-entropy alloy coating is 562.5 HV, and the coating minimum's friction coefficient is 0.352.