Tribological behavior of diamond reinforced FeNiCoCrTi0.5 carbonized high-entropy alloy coating

FeNiCoCrTi0.5)C-x (x = 3 wt%, 6 wt%, 12 wt%) carbonized high-entropy alloy-based composite coatings, marked as C-3, C-6 and C-12, were prepared on 45 steel by laser cladding. The macroscopic morphology, phase, microstructure, hardness and wear resistance of coatings have been investigated systematically. The results indicate that diamond content has a significant influence on the microstructure and mechanical properties of (FeNiCoCrTi0.5)C-x coating. (FeNiCoCrTi0.5)C-x coatings, without pores and cracks, are well metallurgically bonded with substrate. The coatings consist of BCC solid solution, Cr23C6 and TiC. The addition of diamond in (FeNiCoCrTi0.5)C-x coating leads to the instability of BCC solid solution and facilitates the precipitation of carbides, which causes carbides to become coarse and aggregate into large blocks. The hardness of (FeNiCoCrTi0.5)C-x coatings is much higher than that of the 45 steel, the average hardness of C-12 coating is 4 times the hardness of substrate. Besides, the hardness of (FeNiCoCrTi0.5)C-x coating increases with the increase of diamond content. Nonetheless, compared to C-6 coating, the C-12 coating shows inferior tribological performance due to the brittleness. It is noteworthy that C-6 coating with outstanding wear resistance has the potential to apply in various fields of machinery industry, marine engineering and aerospace.