Investigation of molten pool dynamic behaviors in laser additive manufacturing by numerical simulation

Abstract

Laser additive manufacturing (LAM) can provide innovative approaches for designing a lightweight product with load-adapted structures and be widely used in the automotive and aerospace industries. A numerical model taking into account wire feeding and laser absorption is developed in this paper to investigate the dynamic behaviors of a mixing molten pool in the LAM process. Based on this model, flow field distribution and the evolution of molten pool are numerically calculated. The surface of the mixing molten pool during the LAM process is tracked and the evolution of the molten pool is analyzed. The droplet transfer mode of molten wire adding into the molten pool and the influence of Marangoni convection on the surface evolution of the molten pool are discussed by way of simulation results. It is found that the molten pool dynamic behaviors have great influence on the morphology of the formed layer after molten metal solidification in the molten pool. The calculated height and width of the formed layer are validated by the experimental results and good agreement between them is found. Therefore, the proposed method is of importance for controlling the molten metal flowing in the molten pool and the morphology of the formed layer in LAM.