Development of Iron-Based Medium-Entropy Alloy Coatings on Laminar Cooling Rolls by Laser Cladding

A new medium-entropy alloy coating of Fe₅₀Cr₂₂(MnNiCuAlTi)₂₀C₈ was fabricated by laser cladding technology. The microstructure and high-temperature wear resistance of the medium-entropy alloy coating were systematically investigated using experimental equipment such as SEM, XRD, microhardness tester, and high-temperature friction and wear testing machine, and a comparative analysis was conducted with the widely used Rocket431SR laser cladding coating for laminar cooling rolls. The research results showed that the prepared medium-entropy alloy coating was free of common defects such as pores and slag inclusions, formed a stable metallurgical bond with the substrate, and exhibited excellent overall cladding quality. XRD detection results indicated that the medium-entropy alloy coating was mainly composed of body-centered cubic (BCC) phase; SEM analysis revealed that the coating structure was dominated by equiaxed grains, with a small amount of TiC particle precipitates distributed at the grain boundaries, and continuous distribution of Cr23C6 precipitates. This unique microstructure provided an important basis for the coating to possess high hardness and excellent wear resistance. The results of hardness tests and high-temperature wear performance tests showed that the hardness of the medium-entropy alloy coating was as high as 790Hv0.5, which was significantly higher than that of the Rocket431SR coating; under the high-temperature condition of 600°C, its specific wear rate was only 45.4% of that of the Hoganas Rocket431SR coating, showing more excellent high-temperature wear resistance and fully meeting the actual service requirements of laminar cooling rolls.​