Integrated 2D cellular automata-phase field modeling of solidification and microstructure evolution during additive manufacturing of Ti6Al4V

In this work, the as-solidified beta-grain microstructure and concentration evolutions for each solute during the directed energy deposition (DED) of Ti6Al4V are successfully simulated via the combination of two predictive models: A validated 3D DED model is first employed to simulate the thermal history in the multi-track Ti6Al4V depositions. By incorporating the extracted quasi-steady-state temperature profiles as inputs, the novel integrated 2D cellular automata (CA)-phase field (PF) model simulates the grain details and solutal evolution on the sub-grain level over the entire fusion zone, which takes advantages of the high calculation efficiency of the CA component and the broad capability of the PF component. In this 2D CA-PF model, the 2D CA component simulates the dendrite growth and solute redistribution while the 1D PF component calculates the growth kinetics including growth velocity and equilibrium solute partition. Besides, The PF component is coupled with the thermodynamic and solute diffusion mobility data of the Ti-Al-V system such that the solutal evolution of Al and V is predicted successfully. The simulation results are compared with experimental observation and 3D CA modeling results.