Study On FeNiCrCoCu_xMo_y High Entropy Alloy Coating By Laser Cladding

In order to prepare a coating that is both resistant to friction and wear and corrosion resistant in dilute sulfuric acid,the FeNiCrCoCu_x Mo_y high-entropy alloy coating was fabricated on the Q235 substrate by laser cladding technology.The laser process parameters was studied.The microstructure,phase structure,mechanical properties and electrochemical corrosion resistance of FeNiCrCoCu_xMo_y high-entropy alloy coating were investigated by and addition of Cu and Mo elements using metallographic microscope,X-ray diffract meter,scanning electron microscope,energy Spectrometer,microhardness tester,friction and wear tester and electrochemical workstation.At the same time,the corrosion resistance of the optimal FeNiCrCoCu_xMo_y high-entropy alloy coating was studied at 20°C,40°C,60°C and80°C.The results show that the high entropy alloy coating has good surface cladding quality when the laser cladding power P=2.6 kW,the laser scanning speed v=4 mm/s,and the fixed spot diameter is 6 mm.By adjusting the addition amount of Cu element,it is found that the phase structure of FeNiCrCoCu_xMo high-entropy alloy coating has not changed significantly with the addition of Cu,and it is composed of face-centered cubic?FCC?solid solution.The microstructure of the coatings consists of cell branches.The crystals gradually change into columnar dendrites with obvious directionality,and the hardness of coatings is also decreasing.However,they are higher than the substrate,and also exhibit good corrosion resistance in dilute sulfuric acid.The comprehensive experimental results show that the FeNiCrCoCu_0.3Mo coating has outstanding wear resistance,and also exhibits excellent corrosion resistance in dilute sulfuric acid.After optimizing the addition amount of Cu element,by adjusting the addition amount of Mo element,it is found that when x?0.4,the coating is FCC structure.When x>0.4,the phase structure of the coating undergoes phase transformation,and the second phase appears.That is,the alloy is mainly composed of a solid solution phase in which the FCC phase and the molybdenum-rich?phase are mixed.The microstructure of the coating is gradually thinner,but it is a dendritic structure.The average hardness of the coating is increasing and its wear resistance is getting better and better.The coating also showed good corrosion resistance in dilute sulfuric acid.Combined with the corrosion resistance and wear resistance,the FeCoNiCrCu_0.3Mo_0.8high entropy alloy coating was obtained as the best coating for the experiment.By investigating the effects of different temperatures on the corrosion resistance of FeCoNiCrCu_0.3Mo_0.8 high-entropy alloy coating in dilute sulfuric acid,it is found that the coating has excellent corrosion resistance below 40°C.When the temperature is higher than 40°C,it is resistant.Corrosion performance is degraded.