Research Of Organization And Performance Of WC/High Entropy Alloys （AlCoCrFeNi） Laser Cladding Layer

Wear and corrosion is the main reason of material service performance decline,agricultural machinery parts in the process of work because of direct contact with soil sand,plant stem,wear and corrosion seriously lead to the cutting performance,life decline.As a new kind of alloy material,high entropy alloy has become a research hotspot with excellent wear resistance and corrosion resistance.In this paper,AlCoCrFeNi high entropy alloy cladding layer with different WC content（0%,10%,20%,30%）was prepared on 65Mn substrate surface by laser cladding technology.Subsequently,metallographic microscope,scanning electron microscope,energy spectrum analyzer and X-ray diffraction were used to test and analyze the microstructure,micro-area composition and phase of each cladding layer.The hardness and wear resistance of cladding layer were tested by hardness tester and friction and wear testing machine.The electrochemical performance of the cladding material was tested by electrochemical workstation,and the corrosion and wear performance of the cladding material was analyzed.The effects of WC content and corrosion solution type on wear,corrosion and corrosion wear performance of cladding layer were studied.The main results are as follows:The cladding layer of high entropy alloy with different WC content achieves good metallurgical bonding with the matrix,forming cellular,columnar and equiaxed crystal morphology from bottom to surface.The microstructure of cladding layer of high entropy alloy is mainly composed of BCC phase and trace FCC phase.With the increase of WC content,FCC phase weakens or even disappears.There is a gradient distribution of hardness between the cladding layer and the matrix.When WC content is 30%,the maximum hardness of cladding layer can reach 1060 HV0.2,which is 2.52 times that of the matrix（420 HV0.2）.With the addition of WC,the wear resistance of the cladding layer is significantly improved compared with that of the matrix,and the wear resistance decreases first and then increases with the increase of WC content.The wear amount of the cladding layer with 20%WC content is the least,which is about 28.1%of that of the 65Mn matrix at the same time.Under the same conditions,the friction coefficient decreases and the wear increases with the increase of applied load.In three typical environments,the corrosion resistance of high entropy alloy cladding layer is better than that of 65Mn matrix.In 3.5%Na Cl solution,pitting corrosion occurs in the cladding layer,and the corrosion resistance increases first and then weakens with the increase of WC content,and 20%WC cladding layer has the best performance.In 1mol/L Na OH solution,each cladding layer forms a stable passivation film,and the surface corrosion phenomenon is not obvious.The addition of WC does not make the cladding layer have an obvious corrosion resistance trend.In comparison,the performance of the cladding layer with20%WC is relatively low.In 1mol/L H₂SO₄ solution,the cladding layer exhibits small-hole corrosion and intergranular corrosion with strong corrosion degree,and its corrosion resistance increases first and then weakens with the increase of WC content.The cladding layer with 20%WC has the best performance.In the three corrosive media environments,the overall corrosion wear performance of the cladding layer increases first and then decreases with the increase of WC content,and the cladding layer with 20%WC is the best.In 3.5%Na Cl solution,plastic rheology and slight plowing are gradually replaced by brittle peeling promoted by corrosion.The wear amount of20%WC cladding layer is about 49.5%of AlCoCrFeNi cladding layer.In 1mol/L Na OH solution,the cladding layer shows serious adhesive wear and furrow,and the wear amount of20%WC cladding layer is about 47.7%of AlCoCrFeNi cladding layer.In 1mol/L H₂SO₄solution,the cladding layer exhibits serious abrasive wear and adhesive spalling,and the wear amount of 20%WC cladding layer is about 44.6%of AlCoCrFeNi cladding layer.