Effect of laser power on the microstructure and properties of CoCrFeNi-20Y(GN)10 high-entropy alloy composite coatings

In this study, CoCrFeNi-20Y(GN)10 high-entropy alloy composite coatings were fabricated on Q235 steel substrates using laser cladding. The effects of laser power on the microstructure, phase composition, hardness, wear resistance, and corrosion behavior of the coatings were systematically investigated. The results indicate that with increasing laser power, the WC particles gradually decompose, C and W atoms are released into the molten pool, subsequently giving rise to finely dispersed M(Cr,Fe)C carbides and Cr–W–C eutectic structures through their interactions with Cr, Fe, and other constituent elements, thereby significantly enhancing the coating properties. The coating prepared with laser power of 2500 W has the best mechanical properties and the optimal corrosion resistance. Specifically, its hardness is 436 HV_0.2, the friction coefficient is as low as 0.619, the wear rate is as low as 2.963 × 10⁻⁵ mm³/N⋅m, and the corrosion current density is 5.65 × 10⁻⁶ A/cm².