EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Due to the specific advantages of design flexibility, rapid prototyping, and the ability to produce complex geometries additive manufacturing (AM) industry is growing at a cumulative rate of 26% over the last 3 decades. However, the full potential of AM is yet to be realized as there are still many technical challenges owing to a lack of clear understanding of physical mechanisms. It is not always possible to capture these physical mechanisms with experiments as the process itself is instantaneous and these mechanisms are active at different length and time scales.
In the current work, we employ both macroscopic and microscopic simulation models to understand the microstructure evolution during the selective electron beam melting (SEBM) of Ni-based superalloys. Macroscopic CFD simulations are employed to understand the effect of process parameters mainly the beam power, scanning velocity and hatching strategy on the geometry of the melt pool and thermal evolution. The CFD model equations coupled with analytical Rappaz Thevoz (RT) are implemented in OpenFOAM. The results of the CFD model namely the heat extraction rate will act as the boundary condition for the microscopic phase-field model. To account for the accurate thermal evolution inside the PF box, the heat diffusion equation will be solved locally taking the release of latent into consideration. With the PF simulations, we mainly study the evolution of micro-segregations, dendrite arm spacings, solute undercooling, and nucleation phenomena during remelting of previously grown single-crystal SEBM sample.