Computational Study of Transport Phenomena in Laser Melting-Based Metal Additive Manufacturing

A transient, 3D model has been developed to study evolution and constitution of melt pool for a single-pass laser melting-based direct energy deposition process. Here, the powder material, Inconel 718, is deposited on a SS 316 substrate having different chemical composition. The conservation equations for mass, energy, momentum and species have been solved with respect to a reference frame fixed with the moving laser. To study the phase change process, an enthalpy-based technique has been utilized so that a single-domain solution of the problem gives the interface of solid and liquid as part of the solution. The melting of different compositional elements of IN 718 being deposited on the substrate, their vaporization above respective boiling points, and the momentum of carrier and shield gases have been incorporated into the model. The computational model can predict the distribution of species in melt pool and the geometry of the dilution zone.