Investigation of Molten Pool Geometry and Flow Field Based on Powder Scale Modeling in Laser Directed Energy Deposition

Laser directed energy deposition (DED-LB) technology is currently facing challenges in controlling geometry accuracy of metal components. There is an urgent need to develop a numerical model that is more efficient and accurate compared to existing models and to analyze the dynamic behavior of the melt pool under the interaction of process parameters during DED-LB process to optimize parameters with fewer experimental studies to reduce costs. Therefore, a three-dimensional powder-scale multi-physics model is proposed during the single-track DED-LB process in this study. The powder particles are added by a Lagrangian particle model in this model without the need for assuming that the powder particles entering the molten pool are added by the mass source term, which improves model accuracy and efficiency. The effects of energy per unit mass (EUM, J g−1), mass per unit length (MUL, g mm−1), and standoff distance (SD, mm) intensities on transient molten pool motion and flow field are comprehensively investigated. It is discovered that the proposed model is able to predict the single-track height, width, depth, and dilution rate, or less than 9