Forming Of Aluminum Alloy Laser Oscillating Fuse Deposition Research On Heat Transfer Mechanism And Melt Pool Flow

Laser fuse additive technology not only meets the integrated forming of large and complex components,but also has high energy concentration,when heating high-strength aluminum alloy,the penetration ability is strong,and it is easier to realize the additive manufacturing of highstrength aluminum alloy,but due to the high energy of the laser,the aluminum alloy is quickly cooled and porous after heating and melting,resulting in high porosity of the formed components and poor overall deposition performance.In this paper,it is proposed to add laser oscillation to the laser fuse additive technology to achieve the effect of reducing the porosity of the workpiece and improving the forming quality of the workpiece.Through the combination of numerical simulation and experiment,the influence of different oscillation processes on the additive manufacturing of laser fuses is studied.The establishment of the finite element simulation model of laser oscillation fuse additive manufacturing is carried out through ANSYS software,fully considering the heat transfer mechanism in the process of laser fuse additive and the cooling and solidification of the molten pool,using the simplified droplet model,determining the initial size of the droplet model according to the diameter of the selected wire,using the three-dimensional cone heat source model,using the VOF method solid line to freely track the liquid level of the molten pool,and analyzing and calculating the thermophysical properties of 5A06 aluminum alloy to ensure the accuracy of the simulation model.A comprehensive gas-liquid-solid multiphase coupling model was established.Numerical models of the temperature field of additive manufacturing of laser melting filament with different oscillating process parameters were carried out.When it is found that the laser is without oscillation,the area of heat concentration in the molten pool appears in the laser irradiation position,and due to the impact of the laser,a partial depression appears in the irradiation position,and after the contact surface between the depression and the air layer is closed,the air without escape remains inside the molten pool to form pores.When the laser swings,the heating area,depression,and flow of the molten pool will be significantly affected,and the influence of different swing process parameters on the pores of the additive manufacturing of laser fuses is summarized.Laser fuse additive manufacturing experiments with different swing process parameters were carried out,and the deposition process was recorded by high-speed camera,the influence of different swinging processes on droplet transition and molten pool flow in the same cycle was analyzed,and the influence of laser oscillation on droplet transition behavior and molten pool flow was summarized.The numerical simulation forming results and experimental deposition results of laser swing fuse additive manufacturing were studied,the macroscopic forming morphology of the workpiece was observed,and the influence of laser swing process parameters on deposition forming was summarized.The microstructure of the section of the deposited layer was observed and analyzed by light microscope and metallographic observation,and the influence of laser swing process parameters on the pore distribution and microstructure changes of the deposited layer in the process of additive manufacturing of fused filament was studied,and the optimal laser swing fuse additive manufacturing processing technology was summarized.