Prediction of Microstructure for Inconel 718 Laser Welding Process Using Multi-scale Model

The metal additive manufacturing (MAM) process mainly derived from the metal welding process has unique advantages for the die manufacturing and repairing. To obtain the part with fine microstructure, and improve the performance of the complex die structure, the laser powder bed fusion (L-PBF) additive manufacturing process of Inconel 718 has been studied. A model combining finite volume method (FVM) and cellular automata (CA) method was used to explore the feasibility of simulating microstructure growth during the laser melt pool solidification from 2D to 3D. The process parameters of the multi-scale and multi-dimensional simulation were: 200 W (laser power), 1200 mm/s (scanning speed), 90 μm (hatch distance), and 30μm (layer thickness). The simulation result was compared with the experimental result of the same process parameters, and the feasibility of the model was proved. This multi-scale model can provide theoretical guidance for similar processes with focused energy sources and large temperature gradient solidification processes during die forming and repairing in the future.