Study On Controland Tribological Properties Of VAlTiCrCu/WC Multilayer Structure

With the development of science and technology,materials play a pivotal role in the progress of science and technology,and the requirements for materials are getting higher and higher.In recent years,the emergence of high-entropy alloys has attracted the attention of many researchers due to its outstanding comprehensive properties.The research of bulk high-entropy alloy is the main work direction of its research,and the research of coating as a surface modification is relatively few.In this paper,the composite target and magnetron sputtering technology independently developed by our research group are used to controllably prepare high-entropy alloy VAlTiCrCu and nitrided high-entropy alloy(VAlTiCrCu)Nx coatings.And VAlTiCrCu/WC and VAlTiCrCu/(VAlTiCrCu)Nx multilayer structure coatings with different modulation cycles.And systematically studied VAlTiCrCu/WC(VAlTiCrCu single layer with different modulation periods,the modulation periods are: 17 nm,40nm,90 nm,140nm and 350nm)and VAlTiCrCu/(VAlTiCrCu)Nx(VAlTiCrCu single layer,the modulation periods are respectively: 20 nm,50nm,120 nm and230nm and(VAlTiCrCu)Nx single layer)the structure of the multi-layer structure coating and the friction,corrosion and abrasion resistance.The main findings are as follows:(1)At 300℃,the VAlTiCrCu coating prepared by composite target and magnetron sputtering technology,and the calculation of thermodynamic mixing entropy,mixing enthalpy,atomic size difference and valence electron concentration confirms that it meets the thermodynamic criterion of high-entropy alloys.The elements of the coating are evenly distributed,and the crystal structure is a body-centered cubic lattice(BCC)phase.Among the five elements of VAlTiCrCu,both V and Cr have a body-centered cubic lattice(BCC)structure,and Ti can also interact with V It maintains a body-centered cubic lattice(BCC)structure in the state of the alloy.(2)The VAlTiCrCu/WC multilayer structure coating with different modulation periods prepared by the addition of WC still maintains a single body-centered cubic lattice(BCC)phase with uniform element distribution,which does not affect the element distribution and phase structure of the VAlTiCrCu layer.The VAlTiCrCu/(VAlTiCrCu)Nx multilayer structure coating with different modulation periods is also a body-centered cubic lattice(BCC)phase,but the(VAlTiCrCu)Nx coating is a face-centered cubic lattice(FCC)phase.The main reason is that the bottom layer of the coating prepared by the VAlTiCrCu/(VAlTiCrCu)Nx multilayer coating is a VAlTiCrCu coating.Under its induction,the VAlTiCrCu/(VAlTiCrCu)Nx multilayer coating is still a body-centered cubic lattice(BCC)phase.However,the(VAlTiCrCu)Nx coating tends to form a face-centered cubic lattice(FCC)phase without the induction of the VAlTiCrCu underlayer.The VAlTiCrCu/WC multilayer coating with a modulation period of 17 nm has small,dense and uniform grains,and its bonding force is as high as 55 N.The friction performance is 30% higher than that of the high-entropy alloy single layer,and the abrasion performance is increased by 5times.(3)The VAlTiCrCu/(VAlTiCrCu)Nx multilayer coating with a modulation period of 20 nm has fine grains,compactness and uniformity,and its friction resistance is 75% higher than that of a single-layer high-entropy alloy single-layer,and higher than that of a nitrided high-entropy alloy coating Up to60%.The tribo-corrosion resistance is about 4 times higher than that of the high-entropy alloy coating,and about 3 times higher than that of the nitrided high-entropy alloy coating;The hardness and elastic modulus are as high as15.18 GPa and 264.61 GPa,respectively.