Structure And Properties Of Ceramic Phase Reinforced CoCrFeNiCu High-Entropy Alloy

316L stainless steel as a standard austenitic stainless steel has excellent corrosion resistance and good machinability,but its low hardness and poor wear resistance restrict its development to a certain extent.In order to expand the application range of 316L stainless steel and improve its service life under harsh working conditions,surface modification is particularly important.Due to its excellent comprehensive properties,high-entropy alloys can be used as surface modification materials,which have been widely concerned by many researchers.At present,the comprehensive properties of high entropy alloy composites can be enhanced by adding ceramic phase.In this paper,CoCrFeNiCu,CoCrFeNiCu(SiC)x and CoCrFeNiCu(YSZ)x high entropy alloy coatings were prepared on 316L stainless steel substrate by laser cladding coating technology,and their mechanical properties and corrosion resistance were studied,which help to further improve the surface properties of 316L stainless steel.This work provides basic basis and technical support for the research of high entropy alloy and surface modification technology.CoCrFeNiCu material was selected as the basic coating,and CoCrFeNiCu high entropy alloy coating with typical dendritic morphology was prepared by laser cladding coating technology.The results show that the coating thickness increases with the increase of laser power at the same scanning speed.When the laser power is determined,the CoCrFeNiCu high entropy alloy coating prepared at different scanning speeds has good macroscopic morphology and no obvious defects.The single factor experiment shows that when the laser power is 2000 W and the scanning speed is 3 mm/s,the CoCrFeNiCu high entropy alloy coating has the least defects,uniform microstructure and the highest hardness value of 275.6 HV.In the application research of surface modification materials,ceramic particles as reinforcements help to improve the surface hardness and corrosion resistance of materials.The CoCrFeNiCu(SiC)x high entropy alloy coating with simple FCC structure was prepared on the basis of the optimized process.By adding ceramic particle SiC,the CoCrFeNiCu(SiC)x high entropy alloy composite coating with FCC and Cr7C3 phase structure was obtained.With the increase of SiC particle content,the hardness of CoCrFeNiCu(SiC)x high entropy alloy composite coating is much higher than that of 316L stainless steel substrate,about 1.5～3.4 times that of the substrate,and its wear resistance is also improved.The corrosion resistance of the coating in 3.5%NaCl solution was improved by adding appropriate amount of SiC particles.When the addition amount of SiC particles was 15 wt%,the intergranular corrosion occurred in the coating,and the corrosion resistance of the coating was reduced.The service performance of the coating was significantly better than that of the unmodified CoCrFeNiCu high entropy alloy coating.In order to further obtain the high entropy alloy coating with better wear resistance,the CoCrFeNiCu(YSZ)x high entropy alloy composite coating with FCC and YSZ phase structures was obtained by adding YSZ ceramic particles.With the increase of YSZ content,the maximum hardness of CoCrFeNiCu(YSZ)15 coating is 668.4 HV,which is about 4 times of the substrate.The YSZ particles in the coating inhibit the plastic deformation of the high entropy alloy coating,and the YSZ particles play a prominent role in the friction and wear process,which reduces the friction coefficient and wear amount of the coating and improves the friction and wear resistance of the coating.In 3.5%NaCl corrosion solution,the CoCrFeNiCu(YSZ)x high entropy alloy composite coating was passivated,which improved the corrosion resistance of the coating..