Effects of laser power on microstructure and properties of laser cladded CoCrBFeNiSi high-entropy alloy amorphous coatings

The CoCrBFeNiSi high-entropy alloy (HEA) coatings were fabricated on H13 steel using different laser powers. The microstructure, mechanical and chemical properties of the coating and the internal relations between them were investigated, in which 3D wear trace morphology was adopted to analyze the wear resistance of different coatings. The coatings could be divided into three layers with different microstructure including the bottom dendritic layer, the upper amorphous layer and the transition layer. The amorphous content in the coatings was dependent upon laser power which influenced dilution rate and actual cooling rate through changing heat input. Increased amorphous content led to increased microhardness of the coatings which could approach five times of that of the substrate. When the amorphous content decreased, cladded coatings exhibited deeper furrows, more serious adhesive wear and oxidation wear, which gave birth to wider cross section area of the worn track, higher wear weight loss and thus deteriorated wear resistance of the coatings. Moreover, higher amorphous content in the coatings had led to more excellent corrosion resistance to HCl and NaCl solution.