Laser Induced Surface Micro Texture And Properties Of 5052 Aluminum Alloy

Laser surface texturing technology refers to the processing method of making patterns with certain size and direction on the surface of materials by using the high energy density of laser.In fact,the laser surface texture technology comes from nature.In nature,many super hydrophobic,wear-resistant and low friction objects are not completely smooth.It can be found that there are some small gullies on their surfaces through microscopic observation.Therefore,the micro texture processed on the material surface can achieve the effect of improving hardness,reducing wear and improving hydrophobicity.The surface texture technology Technology is widely used in the field of tribology and wettability.In this paper,the surface micro texture of 5052 aluminum alloy was prepared by the interaction of long pulse laser with the surface of 5052 aluminum alloy.The change rule of the surface micro structure morphology of aluminum alloy induced by laser was studied,and the influence of the surface micro texture on the friction and wear properties and wettability was explored.The main contents of this paper are as follows:1.Single pulse laser-induced morphology evolution of 5052 aluminum alloy.Under different average laser power,firstly,by changing different pulse width,the influence of pulse width on the surface morphology is explored,and the most ideal pulse width is selected by considering the morphology parameters,morphology evolution,processing repeatability and other aspects.Based on the pulse width,the influence of pulse energy on the surface morphology was studied.The experimental results show that the influence of pulse width on the diameter and height parameters is different under different average laser power.After comparing the influence of six pulse width on the morphology under different average laser power,it is found that when the pulse width is 300 ?s,the crater morphology is the best.At a pulse width of 300 In ?s,the energy is divided into three stages according to the evolution rule of morphology.In the first stage,the depth of morphology is small,the height of edge bulge is larger than the depth of pit,the diameter of pit continues to increase,and the diameter of heat affected zone also continues to increase;in the second stage,the diameter of pit continues to increase,but the growth rate is not fast,the depth of pit increases rapidly;in the third stage,the edge bulge increases,and the width of edge bulge increases And the height increases rapidly.2.Study on the morphology evolution of 5052 aluminum alloy induced by multi pulse laser.By changing the number of pulses and the average power of laser,the influence of the number of pulses on the morphology is studied,and the differences and similarities of the change rule under diferent average power of laser are discussed.The experimental results show that when the average laser power is 30 W,when the number of pulses increases,the surface morphology changes from convex to concave,and the evolution process is shortened obviously at 35 W,and soon enters the irregular plasma action stage.The main difference between single pulse induction and multi pulse induction lies in the different processing mechanism and surface morphology.3.Laser textured surface preparation and properties of 5052 aluminum alloy.Four kinds of different surface morphology were induced.The friction and wetting properties of four kinds of surface morphology under three kinds of surface density were studied.The experimental results show that in the aspect of friction and wear,the existence of micro texture on the surface of the material can reduce the friction coefficient,and the effect of friction reduction is different with different morphology and friction parameters;in the aspect of wettability,the laser processing makes all the samples appear hydrophilic,and different morphology and surface density have great influence on the contact angle,which is consistent with the experimental phenomenon According to the Wenzel model,all the samples were hydrophobic after the surface treatment of fluorosilane.There was no significant difference in the contact angle of different surface density under the same morphology,and the contact angle was different under different morphology.