Due to the specific advantages of design flexibility, rapid prototyping, and ability to produce complex geometries, additive manufacturing (AM) is attaining tremendous interest from both industry as well as academia. However, the full potential of AM is yet to be realized as there are still many technical challenges owing to lack of clear understanding of physical mechanisms which are active at different length and time scales.

In the current work, we use a multi-scale modelling framework to understand the microstructure evolution during the selective electron beam melting (SEBM) of Ni-based super alloys. At macrosclae, we study the dynamic behavior of the melt pool during the additive manufacturing process of CMSX-4 Nickel superalloy with the help of CFD simulations, implemented in OpenFOAM. To understand the evolution of microstructure under rapid solidification conditions, we employ 3-Dimensional phase-field simulation model. The Multi Phase-Field model is coupled to both mass and heat transport phenomena including release of latent heat of solidification. Nucleation of both primary and secondary phases are included.With the help of this multi-scale framework, we make quantitative predictions for the melt pool geometry and thermal distribution at macroscale and microstructure evolution including the nucleation phenomena, dendrite morphology, volume fractions of primary and secondary phases and microsegregations at microscale.