Numerical analysis of aluminum alloy fused coating process

Aiming at the difficulties in the additive manufacturing process of aluminum alloy, the aluminum alloy fused coating process with arc preheating is proposed. A three-dimensional transient numerical model is established based on the finite difference method. The evolution process of melt flow and spreading is studied, and the interaction effects between the molten fluid and the driving forces were analyzed. The effect of the different distance between the nozzle and the tungsten electrode on the coating process is computed. It is found that when the distance is less than 8 mm, the substrate cannot directly absorb the energy of the arc and the preheating effect of the front heat source is gradually lost. The aluminum alloy melt spread is blocked and spread sideways, and the contour profile of the coating layer begins to become irregular. When the distance is greater than 14 mm, spheroidization occurs at the position of the starting end of the coating layer. Through the analysis of the dimensionless numbers, it is found that in the early stage of the fused coating process, the heat lost by heat conduction in the molten pool is more than that of convection and the influence order of partial driving forces is surface tension > Lorentz force > buoyancy.