Microstructure evolution and frictional wear behavior of laser cladding FeCrCoNiMo0.5Wx high-entropy alloy coatings

Abstract

FeCrCoNiMo0.5Wx (x = 0,0.25,0.5,0.75,1.0) HEA coatings were prepared on Q235 surfaces by laser cladding technique, the microstructure and phase composition of the coatings were analyzed to investigate the corrosion resistance, frictional wear properties, and wear mechanisms. The results showed that the increase of W caused the coating to produce μ phase, and the FeCrCoNiMo0.5Wx HEA coating consisted of FCC solid solution and intermetallic compound σ phase and μ phase. The microstructure of the coating possesses a typical dendrite region (DR)-inter-dendrite (ID) structure, and the grain size is significantly refined after the addition of W. With the increase of W content, the microhardness and wear resistance of the coating gradually increased, among which the microhardness of W1.0 coating was the highest and the wear resistance was the best. The wear mechanism of the coating is mainly oxidation wear, adhesive wear and slight abrasive wear. The addition of a small amount of W promotes the formation of a more stable passivation film. Further increasing the content of W, the phase content of the coating increases, resulting in a highly inhomogeneous passivation film, which reduces the corrosion resistance of the coating. The W0.25 coating has the best overall corrosion resistance.