Microstructure and Wear Characteristics of Laser-Clad CoCrFeMnNiNb_0.3 High-Entropy Alloy Coating

We enhanced the hardness and wear resistance of CoCrFeMnNi high-entropy alloy coatings using laser cladding to produce CoCrFeMnNiNb_X (X = 0, 0.3) coatings on Q235 steel plates. The introduction of Nb elements formed Nb-rich Laves phase and solid solution strengthening in the FCC phase, improving mechanical properties. Electron backscatter diffraction (EBSD) revealed significant grain refinement in the CoCrFeMnNiNb_0.3 coating, enhancing fine-grain strengthening. The nanohardness increased 1.3 times to approximately 6.29 ± 0.18. Elevated values for HU, H/E, and H³/E² indicated superior resistance to plastic deformation. The coating demonstrates commendable wear resistance, evident from an average coefficient of friction measuring 0.459 and a specific wear rate of 3.496 × 10^-6 mm³/N·m. The wear mechanisms encompass abrasive, oxidative, and adhesive wear.