Multi-Phase Field Method for Solidification Microstructure Evolution for a Ni-Based Alloy in Wire Arc Additive Manufacturing

Wire arc additive manufacturing achieves high efficiency and low costs by using a melting wire for directional depositions. Thermal analyses and the finite element method have been applied to predict residual stress and the deformation of fabricated parts. For Ni-based alloy production, a method for predicting solidification microstructure evolution with segregation is needed in order to design precise heat treatment procedures. In this study, a multi-phase field method coupled with a CALPHAD database is developed to simulate the solidification microstructure evolution of a practical Ni-based alloy. Thermal analyses of a wire arc additive manufacturing model were performed by the process modeling of multi-pass depositions with a running cyclic arc. Solidification microstructure evolution was obtained using the temperature profile in each deposited layer by the multi-phase field method. These predicted microstructures are compared with experimental measurements. It is confirmed that the multi-phase field method coupled with the CALPHAD database is effective for predicting solidification microstructure and segregation in the engineering of Ni-based alloys.