Microstructure And Wear Resistance Of Metal/Ceramic Composite Coating Fabricated On Ti6Al4V Using Laser Cladding

Titanium alloy has high strength,low density.As a new type of metal material,it is widely used in aerospace,military weapons,petrochemical industry,and biomedicine.,Ships,machinery processing and other fields.However,due to the certain defects of titanium alloys,such as easy oxidation at high temperature,poor friction and wear properties,low hardness,unstable structure,etc.,the application range of titanium alloys has certain limitations.In recent years,surface treatment of titanium alloys to prepare cladding layers with high hardness and good wear resistance to compensate for its defects has become one of the hot spots in the research field.As a new type of surface treatment technology,laser cladding technology not only contains some of the advantages of traditional surface modification technology,but also has a wide variety of coating materials and sources,low dilution rate,good interface bonding,and coating thickness and thickness.Advantages such as easy control of process parameters.This article focuses on the problem of easy cracking due to the different physical properties of the material between the powder and the substrate when the coating is prepared on the surface of the titanium alloy.The Al-Si with the same composition as the TC4 titanium alloy substrate and the B₄C with high hardness are selected.,TiC,etc.are used as coating materials to prepare coatings by laser cladding to improve the surface wear resistance of titanium alloys.By changing the composition content and type of the pre-layer powder,the type and distribution of ceramic phases generated in situ during the laser cladding process are controlled,the brittleness of the coating is reduced,and the phase,microstructure,and microstructure of the cladding layer are analyzed.The hardness and friction and wear properties explain the formation mechanism of the coating phase and the interface bonding,and reveal the structure and properties of the coating and the reasons for its improvement.In this paper,by changing the element mass ratio of Al-Si powder,laser cladding TC4 titanium alloy can prepare a cermet composite coating with good interface bonding with the substrate,high hardness and good wear resistance;and the content of the coating The phase is mainly composed of Ti Si compound,Ti Al Si compound,Ti Al compound and other hard reinforcing phases.These phases can play the role of structure refinement and make the coating denser;where Al:Si=3:1（wt.%）Higher hardness and better wear resistance.In order to further improve the surface wear resistance of the coating,B₄C with high hardness is added to the Ti-Al-Si powder to prepare the coating.B₄C reacts with Ti to form TiC,Ti B,Ti B₂,and Ti B₂ reacts with Ti to form Ti B.These substances are all ceramic reinforcing phases.Moreover,Ti-Al-Si generates Ti Si compound,Ti Al Si compound,Ti Al compound and other reinforcing phases in the laser cladding process,which can be beneficial to significantly improve the hardness and wear resistance of the coating.The experimental results show that when the B₄C content is too large,cracks will occur,which will affect the overall hardness and friction and wear properties of the coating.The coating with 8%B₄C content has the best hardness and wear resistance.Different content of TiC is added to Ti-Al-Si powder to prepare pre-layer powder.In-situ reaction of laser cladding technology can produceα-Ti,TiC,Ti Si compound,Ti Al Si compound,Ti Al compound,Ti₃Al C₂ and other reinforcing phases.,Is conducive to the preparation of coatings with high hardness and good wear resistance.However,the content of TiC should not be too high,otherwise the coating will crack or part of the TiC will not melt.The results show that the overall performance of hardness and wear resistance of the TiC coating with a mass ratio of 6%is the most excellent.In order to further obtain a finer structure and better performance coating,different content of Y₂O₃ is added to a certain content of TiC and Ti-Al-Si mixed powder to prepare a pre-layer powder,which can be produced by laser cladding technology Ti Si compounds,Ti Al Si compounds,Ti Al compounds,Ti₃Al C₂ and other phases will also generate TiC,Y₂O₃,Al₂O₃,Ti O₂ and Si O₂.The results show that the more Y₂O₃ content,the finer the structure,but when the Y₂O₃ content is too much,cracks and pores will appear.With a mass ratio of 1%,Y₂O₃coating has the best overall performance of hardness and wear resistance.