Investigation Of CoCrFeMnNi System High-entropy Alloy Coatings By Tungsten Inert Gas Cladding On 06Cr19Ni10 Steel

Being widespread concerned, high-entropy alloy, breaking the shackles of traditional design theory of alloys, which is regarded as a kind of potential candidate cladding material for its simple structure and excellent performance by many researchers. CoCrFeMnNi system high-entropy alloy coatings are clad on the surface of 06Crl9Nil0 stainless steel by tungsten inert gas cladding. The atomic radii difference parameters, mixing enthalpy and mixing entropy of the high-entropy alloys in this system are calculated. Phase formation of each high-entropy alloy is qualitatively predicted by double-factor and triple-factor methods. The crystal structure, microstructure, micro-area chemical composition and microhardness of CoCrFeMnNbxNi, CoCrFeMnMoxNi, CoCrFeMnNiWx (x=0.5,1.0,1.5,2.0; molar ratio) high-entropy alloy coatings are analyzed systematically by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and microhardness tester, respectively. And the wear resistance and corrosion resistance are analyzed and discussed. The results shows that:The calculated results of the double-factor method and the triple-factor method shows that, all of CoCrFeMnNbxNi, CoCrFeMnMoxNi, CoCrFeMnNiWx (x=0.5,1.0,1.5,2.0) high-entropy alloys are in conformity with the scope of solid solution type high-entropy alloys.CoCrFeMnNbxNi high-entropy alloy coating mainly consists of FCC solid-solution and Laves phase. The lamellar spacing of lamellar colonies in CoCrFeMnNbNi, CoCrFeMnNb1.5Ni high-entropy alloy coatings is fine to nanoscale, and nanoparticles are found to precipitate in CoCrFeMnNb1.5Ni high-entropy alloy coating. The average microhardness of CoCrFeMnNb2Ni high-entropy alloy coating with highest hardness can be above 700 HV0.2. The wear resistance of all coatings are superior to that of 06Crl9Nil0 stainless steel. CoCrFeMnMb2Ni high-entropy alloy coating have the most excellent wear resistance among the system. In 3.5%(mass fraction) NaCl solution, the corrosion resistance of all coatings is superior to that of 06Cr19Ni10 stainless steel. The corrosion current density of CoCrFeMnNb1.5Ni high-entropy alloy coating with the best corrosion resistance is an order lower than that of 06Cr19Ni10 stainless steel.CoCrFeMnMoxNi high-entropy alloy coatings mainly consist of FCC solid-solution and rhombohedral solid-solution. The lamellar spacing of lamellar colonies in CoCrFeMnMoNi high-entropy alloy coating is found to be submicron scale to nanoscale. The minimum lamellar spacing of CoCrFeMnMo1.5Ni high-entropy alloy coating is fine to be about 120 nm, and rather nanostructures are found to precipitate in CoCrFeMnMo2Ni high-entropy alloy coating. The average microhardness of CoCrFeMnMo2Ni high-entropy alloy coating with highest hardness can be above 700 HV0.2. The wear resistance of all coatings are superior to that of 06Cr19Ni10 stainless steel. Both CoCrFeMnMoNi and CoCrFeMnMo2Ni high-entropy alloy coating can greatly improve the wear resistance of 06Cr19Ni10, moreover, CoCrFeMnMo2Ni high-entropy alloy coating has the best wear resistance. In 3.5% NaCl solution, the corrosion resistance of all coatings is superior to that of 06Cr19Ni10 stainless steel. The corrosion current density of CoCrFeMnMo1.5Ni and CoCrFeMnMo2Ni high-entropy alloy coating is an order lower than that of 06Cr19Ni10 stainless steel, and CoCrFeMnMo2Ni high-entropy alloy coating has a good passivation behavior.CoCrFeMnNiWx high-entropy alloy coating mainly consists of FCC solid-solution, η phase and M23C6. The eutectic (η phase+FCC solid-solution) and the eutectic (M23C6+FCC solid-solution) are herringbone in CoCrFeMnNiW and CoCrFeMnNiW1.5 high-entropy alloy coating, and the microstructure of CoCrFeMnNiW 1.5 high-entropy alloy coating is finer than the other one’s.η phase is largesized and does not contribute to the formation of eutectic. The average microhardness of CoCrFeMnNiW 1.5 and CoCrFeMnNiW2 high-entropy alloy coating with highest hardness can be above 700 HV0.2. The wear resistance of all coatings are superior to that of 06Cr19Ni10 stainless steel. The wear resistance of CoCrFeMnNiW, CoCrFeMnNiW 1.5 and CoCrFeMnNiW2 high-entropy alloy coating is excellent, moreover, CoCrFeMnNiW2 high-entropy alloy coating has the best wear resistance. In 3.5% NaCl solution, the corrosion current density of the coatings and 06Cr19Ni10 stainless steel are in the same order of magnitude except for CoCrFeMnNiW high-entropy alloy coating.