A Study On Process Technology And Surface Wettability Of Picosecond Laser Texturing Metal

Under the background that countries around the world compete for holding the highland of science and technology,the components and parts with bionic functional surface have been used in many fields of science and engineering,such as aerospace,biomedicine,national defense and so on.By integrating galvanometer scanner with ultrafast lasers,the laser etching technology has characteristics of short pulse width,high peak power and noncontact processing and so on.It is an ideal technology for manufacturing biomimetic surface high precisely and which can be used to fix the bionic performance on the material by laser texturing.In our work,the technique of texturing metal surface by picosecond laser and galvanometer scanning were studied:(1)The mechanism of picosecond laser processing metal and material surface wetting process were studied.The absorption of metal at different wavelengths,the model of interaction between picosecond laser and metal,double temperature equation,and the model of wetting process were analyzed.(2)Laser surface texturing of 2024 aluminum alloy with picosecond laser was studied.The influence of laser processing parameters including laser pulse energy,pulse repetition frequency,scanning times,overlapping rate on the etching morphology,including width,depth and roughness,has been thoroughly studied.That is the base for texturing bionic functional surface.(3)The relationship between the wettability of metal surface and the texture density and roughness(Ra)was studied in experimentally.By orthogonal experiment on different density texture processing,the influencing degree of factors such as laser single pulse energy,laser frequency,overlapping rate,scanning times on textured surface roughness has been studied.(4)The super-hydrophobic metal surfaces with different bionic properties were prepared by experiments,including "lotus leaf" surface,"rose petal" surface,and "blue morpho butterfly wing" surface.(5)In order to meet the adaptation requirements of engineering parts processing,the method to control etching depth on metal surface and crest-trough amplitude of wave shape texture was studied.Classified the region of super-hydrophobic texture,quasi superhydrophobic texture,wettability maintained texture according to the relationship between the wettability and the amplitude of texture,which laid the foundation for the engineering application of metal textured surface with wetting behavior adjustable.