Influence of the synergistic effect of rare-earth biphasic particles on wear properties of high-entropy alloy coatings prepared by extremely high-speed laser cladding

High-entropy alloy (HEA) coatings can effectively improve the wear properties of light alloys. CeO 2 and Y 2 O 3 are two common rare-earth oxides that are often used as dopants to modify the structure and properties of the HEA coatings. In this paper, the HEA coatings of undoped (H 0 ), doped with CeO 2 (H 1 ), Y 2 O 3 (H 2 ), and CeO 2 +Y 2 O 3 (H 3 ) were prepared by extremely high-speed laser cladding (EHLC). The effects of rare-earth biphasic particles and their synergistic effects on the microstructure and wear properties of the coatings were investigated. The results show that single CeO 2 /Y 2 O 3 doping can effectively improve the body-centered cubic (BCC) phase content and refine the grain structure of the coating, but when CeO 2 and Y 2 O 3 are co-doped, the BCC phase content of the coating can be improved more significantly, and the grain refinement is more obvious. Furthermore, the synergistic action of CeO 2 and Y 2 O 3 in the H 3 coating resulted in a significant enhancement of the effects of solid solution strengthening, lattice distortion, and fine-grain strengthening within the microstructure. This resulted in a substantial increase in the microhardness of the H 3 coating, reaching 970.36HV, with a wear rate of merely 1.87×10 −5 mm 3 /(N·mm). In comparison with the H 0 , H 1 , and H 2 coatings, the hardness increased by 1.54 times, 1.51 times, and 1.26 times, respectively. Concurrently, the wear rates decreased by 15.77%, 12.83%, and 11.23%, respectively. The primary wear mechanisms observed in the coatings include abrasive wear, adhesive wear, and oxidative wear.