Study On Microstructure And Properties Of CoCrFeNiTi_xAl_y/SiC High Entropy Alloy Coating Prepared By Laser Cladding

45#steel is widely used in daily life,but the hardness of 45#steel itself is relatively low,and its wear resistance and corrosion resistance are relatively poor,which restricts its further application.As a new type of multi-principal alloy material,high-entropy alloy can form a simple solid solution structure with high hardness and excellent wear resistance and corrosion resistance.The high-entropy alloy coating can effectively improve the surface properties of45#steel.In this paper,45#steel was selected as the substrate,and 4 kinds of entropy alloy coating,CoCrFeNiTi_0.5Al_0.5,CoCrFeNiTi_0.2Al_0.8,CoCrFeNiTi_0.5Al_0.5/SiC_0.1 and CoCrFeNiTi_0.2Al_0.8/SiC_0.1 were prepared by laser cladding technology.The morphology of the high-entropy alloy coating was observed and analyzed by OM and SEM,and the phase structure of the high-entropy alloy coating was studied by XRD.Microhardness,corrosion resistance and wear resistance of CoCrFeNiTi_0.5Al_0.5,CoCrFeNiTi_0.2Al_0.8,CoCrFeNiTi_0.5Al_0.5/SiC_0.1 and CoCrFeNiTi_0.2Al_0.8/SiC_0.1 high-entropy alloy coatings were studied.The study found that CoCrFeNiTi_0.5Al_0.5 and CoCrFeNiTi_0.2Al_0.8 alloy coatings are typical dendritic microstructures,in which the dendritic region is rich in Ni and Al elements,and the interdendritic region is rich in Fe and Cr element.The CoCrFeNiTi_0.5Al_0.5 alloy coating is composed of BCC1+BCC2 and FCC phases,and the CoCrFeNiTi_0.2Al_0.8 alloy coating is composed of FCC+BCC1 dual phases.As the content of Al element increases and the content of Ti element decreases,the microhardness of the CoCrFeNiTi_0.2Al_0.8 alloy coating is reduced by 16%,and the wear resistance and corrosion resistance of the coating are significantly reduced.After adding SiC particles to the CoCrFeNiTi_xAl_1-x high-entropy alloy coating,based on the composition of the original phase structure,the new phase Cr₂Fe₁₄C distributed along the grain boundary appeared in the coating,and the grain and grain boundary distribution of the coating was more obvious.The grain size becomes smaller.After adding SiC particles,the microhardness of the CoCrFeNiTi_0.5Al_0.5 and CoCrFeNiTi_0.2Al_0.8 alloy coatings is significantly improved,and the average microhardness of the CoCrFeNiTi_0.5Al_0.5/SiC_0.1 alloy coating reaches 864 HV,which is higher than that of CoCrFeNiTi_0.5Al_0.5,the average microhardness of the CoCrFeNiTi_0.5Al_0.5alloy coating has increased by 16%.The wear resistance of the two coatings can also be further improved.Among them,the average friction coefficient of CoCrFeNiTi_0.5Al_0.5/SiC_0.1 is the lowest,which is 0.29.The wear resistance of the two alloy coatings has been improved.