Effect of Mo on the Microstructure and Properties of Fe 0.5 CoCrNi 1.5 Nb 0.68 Mo x Remelted High‐Entropy Alloy Coatings

This study investigates the effect of Mo addition on the phase composition, microstructure, wear resistance, and corrosion behavior of remelted Fe 0.5 CoCrNi 1.5 Nb 0.68 Mo x ( x = 0.0, 0.1, 0.3, 0.5) high‐entropy alloy (HEA) coatings. The coatings are fabricated through laser cladding followed by laser remelting to enhance their properties. Results indicate that the remelted HEA coatings comprise a face‐centered‐cubic (FCC) matrix, Laves phase, and NbC, where the FCC phase dominates the structure, the Laves phase serves as the main strengthening constituent, and NbC is sparsely distributed. Increasing Mo content promotes the formation of the Laves phase, resulting in microstructural evolution from columnar to refined dendritic structures, along with an interdendritic network. The Laves phase effectively impedes further dendritic growth and suppresses the FCC phase, leading to grain refinement and improved phase distribution. Notably, the Fe 0.5 CoCrNi 1.5 Nb 0.68 Mo 0.5 coating exhibits enhanced microhardness and wear resistance due to the increased Laves phase. Additionally, Mo dissolution in the FCC phase improves corrosion resistance by reducing pitting susceptibility. This study elucidates the relationship between Mo addition, Laves phase formation, and microstructural evolution, providing a theoretical basis and experimental reference for optimizing the performance of HEA coatings.