Improving the Microstructure and Wear Behavior of Gas Turbine Compressor Parts Through the Application of FeCoNiCuAl-WC High Entropy Composite Coating by Laser Cladding

To improve the wear resistance properties of gas turbine compressor parts, a high entropy alloy (HEA) coating of FeCoNiCuAl with 60% WC ceramic particles was prepared on GTD-111 superalloy with laser cladding (LC). For this purpose, Fe, Co, Ni, Cu and Al elemental powders with high purity were subjected to mechanical alloying (MA) for up to 50 h. Changes in crystallite size and lattice strain at different time intervals of MA were determined by XRD. The XRD results showed that after 50 h of MA, a two-phase HEA solid solution with almost the same aspect ratio, crystallite size of 8.35 nm, and lattice strain of 1.78% was obtained. After preparing the HEA powder, and adding 60% WC ceramic powder to it, the above composite coating operation was done by LC. It was shown that the added WC decomposed and formed in situ carbides. These carbides include WC, W2C, and Co4W2C, which are formed with uniform distribution without cracks or holes in the coating. The characteristics of melting and rapid solidification in LC and non-homogeneous nucleation of melt from WC particles reduced the appearance of misorientation grains and increased high-angle grain boundary (HAGB). These things also caused a decrease in the friction coefficient of the coating by 27% and an increase in the microhardness of the coating by 97% compared to the substrate. Investigations showed that the presence of WC particles has a significant effect on increasing the hardness and reducing the wear volume of the specimens.