Tribological electrochemical and mechanical properties of FeCoNiCrAlx high-entropy alloy coatings prepared by laser cladding on 316 stainless steel

FeCoNiCrAl_x high-entropy alloy (HEA) coatings were synthesized on 316 stainless steel (SS) using laser cladding. The influence of Al content on the phase composition, microstructure, tribological behavior, electrochemical performance, and mechanical properties of the coatings was comprehensively examined. The findings reveal that the phase structure of the HEA coatings transitions from a single FCC phase (x = 0, 0.3) to a dual FCC + BCC phase (x = 0.5, 0.7) and ultimately to a single BCC phase (x = 1.0). With increasing Al content, the microstructure evolves from columnar to equiaxed crystals, accompanied by progressive grain refinement. This grain refinement enhances the hardness of the coatings, which correlates positively with improved tribological properties. At x = 1.0, the coating demonstrates the lowest wear rate. Conversely, the corrosion resistance decreases as Al content increases, with the minimum corrosion current density observed at x = 0 (22.491 μA·cm⁻²). Furthermore, the tensile properties improve initially and then deteriorate with increasing Al content, achieving optimal mechanical performance at x = 0.5. In conclusion, the HEA coatings significantly enhance the tribological, electrochemical, and mechanical properties of 316 SS.