Study On The Wettability Of Aluminum Alloy Surface Microstructure Based On WEDM

The properties of superhydrophobic surface are determined by the chemical composition and surface microstructure of the material.The surface microstructure can be divided into sub microstructure and micro nano structure from the scale.According to Cassie Baxter model and Wenzel model,the existence of microstructure can make the material surface show excellent performance.It is very important to study the prediction theory of water drop on the surface of microstructure for guiding the surface design of microstructure and reducing the design cost.In EDM,there is no macro cutting force between electrode and workpiece.The surface roughness can be changed by controlling the energy,and the complex shape can be made by the way of anti handcuffing and increasing the axis.The important step of superhydrophobic surface preparation is the processing of surface microstructure.EDM has a broad application prospect in the preparation of superhydrophobic surface.In this paper,the surface morphology of EDM is studied by simulation.The simulation model of EDM is established to study the forming process of machining surface by the coupling of thermal field and flow field.In EDM,the distribution of discharge points is random.In order to make the position of discharge point in simulation more consistent with the actual situation,the random number is generated as the position of discharge point by the random function.The expansion process of discharge channel is considered.In traditional Gauss Based on the heat source,the heat source is improved.The surface morphology obtained by simulation is analyzed,and the surface morphology model is established by using the average pit size.The surface roughness and surface roughness coefficient are calculated by the established model,and the variation law of surface roughness coefficient with electrical parameters is studied.The size and shape of submicron microstructure have a great influence on the contact angle of droplets on the material surface.When the size is appropriate,the wetting state of droplets on the material will be Cassise-Baxter model.In this paper,we design the micro structure with rectangular section and semicircle section and array in a single direction.Finally,the prediction formula of the contact angle of the droplet on the semi-circular cross-section microstructure is established.According to the Wenzelmodel,the contact angle of water droplets on the surface of material will be affected.In order to make the prediction model more accurate,the designed microstructure is the primary structure,and the pits on the microstructure are the secondary structure.The surface morphology of EDM is studied by experiments.The influence of the concentration of discharge points on the surface morphology is considered.The simulated surface morphology is corrected.The maximum difference ratio after correction is 4.514%.Superhydrophobic surface was prepared,and the influence of microstructure size and shape on contact angle was studied.The maximum difference between measured contact angle and predicted contact angle was 5.07°.