Study On Properties Of Laser Cladding Co07 Powder In Titanium Alloy For Vehicles

Titanium alloys have become an important choice for automotive lightweight materials due to their excellent specific strength and comprehensive mechanical properties,which are the reasons that why it were widely used in automobiles,aerospace and marine industries.Laser cladding technology can significantly improve the surface wear and corrosion resistance of titanium alloys surface and promote its further development in the automotive industry.In order to improve the wear and corrosion resistance of titanium alloy in the service environment of automobile,Cobased powder Co07 was selected as the cladding material,and the Co-based coating was prepared by laser cladding on the surface of titanium alloy to improve its wear resistance and corrosion resistance to extend its service life in the service environment of the vehicle.The main research contents of this paper include the process optimization of titanium alloy coating for vehicle,the analysis of normal temperature and high temperature friction and wear of titanium alloy coating,the corrosion resistance analysis of titanium alloy coating,microstructure of titanium alloy,phase composition and element distribution analysis.Finally,the subject is studied to the effect of scanning speed change on the coating performance under the vehicle service environment.Firstly,orthogonal test method and orthogonal matrix analysis method are used to optimize the laser process parameters of current,pulse width and frequency with dilution rate and microhardness as the horizontal index,and the titanium alloy coating for vehicle is prepared by using the optimal parameters..Secondly,analyze the vehicle's friction and corrosion service environment.The friction and wear test of the titanium alloy coating for the vehicle is carried out at room temperature and high temperature.The wear resistance of the titanium alloy and its coating is compared and analyzed from the normal temperature and high temperature friction and wear coefficient and weight loss.The field-scanning scanning electron microscope was used to analyze the friction and wear morphology and element composition of titanium alloy coatings.The friction and wear 3D topography was used to analyze the friction and wear mechanism of titanium alloy and its coating.The electrochemical corrosion test of titanium alloy coatings for automobiles in 3.5wt% NaCl and 1mol/LH₂SO₄ solution was carried out by using electrochemical workstation.The open-circuit potential,self-corrosion potential and corrosion current density of automotive titanium alloy and its coatings were compared and analyzed from the open-circuit voltage curve and potentiodynamic polarization curve,and then the corrosion resistance tendency and corrosion rate of automotive titanium alloy and its coatings in the above corrosion environment were analyzed.Microstructure,element distribution and phase composition of automotive titanium alloy coatings were analyzed by optical microscopy,field emission scanning electron microscopy and X-ray diffraction.Finally,the influence of scanning speed on the performance of titanium alloy cladding in vehicle service environment was studied.The effects of scanning speed on friction and wear coefficients,weight loss and morphology of coatings at room and high temperatures were studied.The effects of scanning speed variation on the open circuit potential,self-corrosion potential and corrosion current density of the coating in 3.5wt% NaCl and 1mol/L H₂SO₄ solution were studied.The effect of scanning speed on the phase composition and element distribution of the coating was studied.