High-fidelity multiphysics modeling of laser powder bed fusion: Coupling laser absorption, vaporization, and powder heat transfer

Laser Powder Bed Fusion (LPBF) involves strongly coupled physical phenomena that are difficult to reproduce and validate. In this work, we develop a high-fidelity multiphysics model within the open-source CFD framework OpenFOAM that overcomes key algorithmic limitations of existing approaches. The model incorporates (i) multi-element vaporization, (ii) temperature- and phase-dependent laser absorptivity, (iii) a computationally efficient treatment of laser attenuation and scattering by the vapor plume, and (iv) an improved powder-bed representation using a non-binary initialization of the Volume of Fluid (VOF) field. This approach avoids artificial interface diffusion and enables accurate prediction of powder–gas free surfaces, thermal conductivity in partially dense regions, laser reflections, and melt pool heat transfer. The model is validated against in-situ synchrotron X-ray imaging and laser absorption measurements for Ti-6Al-4V and SS316L over a wide processing window. The results show that neglecting any of these physical contributions leads to substantial errors in melt pool morphology and absorbed energy. A sensitivity analysis quantifies the influence of individual material and process parameters. Overall, the model bridges critical gaps between simulation and in-situ characterization and provides a predictive and extensible framework for advancing LPBF process understanding. • A high-fidelity multiphysics LPBF model is developed in OpenFOAM. • Realistic powder-bed heat transfer is captured using non-binary VOF initialization. • Temperature- and phase-dependent laser absorptivity and vapor plume attenuation are included. • The model is validated against in-situ synchrotron imaging and laser absorption data. • Sensitivity analysis quantifies the influence of key physical mechanisms on melt pool behavior.