Computational Modelling and Experimental Validation of Single In625 Line Tracks in Laser Powder Bed Fusion

Laser track experiments are performed using INCONEL® nickel-based powder alloy, IN625, in a Powder Bed Fusion (PBF) system. Optical microscopy is used to obtain key track dimensions and morphology for various machine parameters, allowing direct validation of ESI Group’s ICME suite of tools for modelling AM. The high-fidelity powder bed model simulates the melt pool formation based on solution of the Navier-Stokes equations and heat transfer, radiative powder-laser interaction, phase change, surface tension, Marangoni forces and recoil pressure. Models are enhanced by measured thermophysical material properties. Validation of the solidified melt geometry showing that conductive mode melting and instabilities such as balling can be captured with existing models and pave the way for models which capture the onset of keyholing. Examination of the melt track microstructures can also be used to determine local cooling rates, granting insight into the phase evolution differences between the alloys.