Microstructure and Elements Concentration of Inconel 713LC during Laser Powder Bed Fusion through a Modified Cellular Automaton Model

Abstract

In this study, a hybrid finite element (FE) and cellular automaton (CA) model is developed to explore crystallization behavior and alloying of Inconel713LC during Laser powder bed fusion. A cellular automaton model is considering the surface nucleation, equiaxed bulk nucleation, and grain growth kinetics. In addition, the equation for solute diffusion is coupled with a cellular automaton model to simulate the IN713LC elements segregation. During the phase change, the non-equilibrium segregation model is applied to insert the effect of ultra-fast solidification happening during LPBF. It is found that, during LPBF processing of IN713LC, the micro segregation of Nb, Ti, and C is accrued at the grain boundaries. It is further shown that the micro segregation intensity depends on the solidification speed, which is determined in turn by the laser heat input. In particular, a lower laser heat input increases the solidification speed and results in a more uniform solid phase, thereby reducing the risk of crack formation. Finally, using a comparison between simulation results and experimental observation, it was shown that the proposed model successfully predicts the bulk element concentration of IN713LC after laser melting.