Finite element simulation of laser additive melting and solidification of Inconel 718 with experimentally tested thermal properties

Powdered metal additive manufacturing technology shows great promise in the aerospace industry. Accurately simulating the associated processes will allow process windows and physical phenomena to be thoroughly investigated without the need for costly and time consuming experiments. The authors have expanded upon previous thermal finite element models by including mass and momentum balance equations which allow for the direct simulation of fluid flow in addition to thermal transport. This is accomplished by the incorporation of the forced rigidity method which utilizes a temperature dependent dynamic viscosity to model melting, flow, and subsequent solidification in all three spatial dimensions. This work includes a sophisticated finite element model that is validated with in-house experiments, as well as experimental determination of thermal conductivity of gas-atomized Inconel 718 powder particles. Through simulation and experimental findings a novel method of modeling the complete physics associated with powder bed additive manufacturing processes is presented.