Microstructure And Properties Of Laser Cladding AlCrFeNiCuMox High Entropy Alloy

The working environment of agricultural machinery is harsh,and the key parts are easy to fail due to corrosion,wear and other reasons.High entropy alloy has excellent wear resistance and corrosion resistance.It is used for the key parts of agricultural machinery,which is conducive to improving its life.In this paper,high entropy alloy Al Cr Fe Ni Cu Mox cladding layers with different Mo contents were prepared on the surface of 65Mn matrix material by laser cladding technology.X-ray diffraction,metallographic microscope,scanning electron microscope and energy spectrum analyzer were used to detect the phase composition and microstructure of the material.Friction and wear testing machine was used to detect the wear resistance of the material.Electrochemical workstation was used to test the corrosion resistance of the materials.The effects of Mo content on wear resistance,corrosion resistance and corrosion wear properties of high entropy alloy cladding layers were analyzed.Specific research results are as follows:（1）The high entropy alloy cladding layers with different Mo content can form metallurgical bonding with the matrix.The samples are divided into cladding zone,bonding zone and matrix zone from the top to the matrix.The high entropy alloy cladding layer is composed of BCC+FCC phase.With the increase of Mo element content,the content of BCC phase increases first and then decreases.The content and hardness of BCC phase of Al Cr Fe Ni Cu Mo_0.6 high entropy alloy cladding layer are the highest.The highest hardness of the high entropy alloy cladding layer is 718HV,which is 2.6 times that of the base material and1.6 times that of Al Cr Fe Ni Cu.It has good wear resistance under different loads,and the wear mechanism is abrasive wear and plastic deformation,fatigue wear and abrasive wear.（2）In 3.5%Na Cl solution,galvanic corrosion occurs in the high entropy alloy cladding layer.Appropriate Mo element helps to inhibit the decomposition of Cr₂O₃ passivated film,thus enhancing the corrosion resistance of the high entropy alloy cladding layer.Too much Mo element will aggravate the lattice distortion effect and increase the potential difference,resulting in the decline of the corrosion resistance of the high entropy cladding layer.Al Cr Fe Ni Cu Mo_0.6 high entropy alloy cladding layer has the best salt resistance.In 1mol/L H₂SO₄ solution,the corrosion behavior is mainly intergranular corrosion and cavity corrosion.Appropriate amount of Mo will promote the generation of Mo O₃ passivation film and enhance the corrosion resistance of high entropy alloy cladding layer.Too much Mo element will aggravate the lattice distortion effect,resulting in the emergence of intergranular gaps and the decline of corrosion resistance of high entropy alloy cladding layer.Al Cr Fe Ni Cu Mo_0.6 high entropy alloy cladding layer has the best acid resistance.（3）In the corrosion wear test of 1mol/L H₂SO₄ solution and 3.5%Na Cl solution,the corrosion wear resistance increased first and then decreased with the increase of Mo content.In 3.5%Na Cl solution,the average friction coefficient and weight loss of Al Cr Fe Ni Cu Mo_0.6are 0.75 times and 0.62 times of that of Al Cr Fe Ni Cu high entropy alloy cladding layer.Corrosion wear mechanism is surface adhesion to plastic deformation,ploughing.In 1mol/L H₂SO₄ solution,the average friction coefficient and weight loss of Al Cr Fe Ni Cu Mo_0.6 are 0.79times and 0.69 times of that of Al Cr Fe Ni Cu high entropy alloy cladding layer.The corrosion wear mechanism is mainly plastic spalling,delamination and furrow.