Experimental and Numerical Study of Single Track Formation in the Laser Powder Bed Fusion Process of AlSi10Mg

This study presents an experimental analysis and computational fluid dynamics (CFD) model for studying single-track formation in the Laser Powder Bed Fusion (LPBF) process, implemented in OpenFOAM. The model incorporates key physical phenomena, including Marangoni convection, recoil pressure, and phase change, to accurately capture melt pool dynamics. A stochastic powder size distribution, statistically characterized from experimental observations, is used as the initial condition to enhance the fidelity of the simulations. AlSi10Mg single-track deposits were performed using a Concept Laser M2 LPBF system, varying laser powers, scan velocities, and spot sizes. Cross-sectional microscopy and porosity analyses revealed transitions from lack-of-fusion to keyhole-induced porosity as a function of volumetric energy density (VED). Numerical results showed good qualitative and quantitative agreement with experimental observations, with relative errors in melt pool dimensions below 12%. Simulations further revealed transient flow patterns and melt pool instabilities difficult to capture experimentally. The findings demonstrate that the combination of experimental observations and simulation tools can be used to construct map process windows, predict defects, and support process optimization in LPBF, understanding the multiphysics phenomena at different building conditions, which is particularly important for high-conductivity aluminum alloys.