Multiphysics Modelling of Laser Powder Bed Fusion Based Additive Manufacturing of Single-Track Build of Ti6Al4V Alloy

Ti6Al4V alloy has wide range of applications in various fields of engineering such as aerospace, marine and medical due to its high strength to weight ratio and high temperature stability. The demand for Laser Powder Bed Fusion (LPBF) is driven by its exceptional capability to produce intricate shapes and components that pose challenges in traditional manufacturing techniques. LPBF is an additive manufacturing process which deals with the powder bed fusion of metallic, polymer as well as ceramic powder particulates. The present study investigates the melt pool behaviour and its characteristics with the help of a computational fluid dynamics (CFD) based numerical model, in case of a single-track analysis. The developed high-fidelity CFD model solves the conservation equations of mass, momentum and energy adopting finite volume method. It is found that the convective heat transfer serves as the dominant heat transfer mode while laser beam travels across the powder bed. The simulation findings include temporal evolution of melt pool geometry such as bead height, bead width, cooling rate and solid fraction of the simulated track deposition. The accuracy of the developed coupled DEM-CFD model is confirmed from experimental validation of single-track deposition of Ti6Al4V alloy, which closely matches the numerical prediction of cylindrical bead profile in the longitudinal direction and hemispherical bead profile in the bead cross section. Along with qualitative validation of bead profile, experimental results match reasonably well with the simulation findings in terms of bead width and its height.