Development of a predictive multi-material and multi-physics model based on volume-of-fluid for simulating wire laser additive manufacturing process

Wire Laser Additive Manufacturing (WLAM) has been widely applied in production technologies for creation of complex geometry and repairing. This process involves numerous coupled physical phenomena, such as laser-material interaction, phase transformations (solid and liquid), fluid dynamics within the melt pool, and heat transfer, making it extremely complex to analyze and observe experimentally. Recently, the use of a wire made from a metal different from the substrate has gained in popularity to create functionally graded material. This approach is particularly attractive for adding new functionalities to existing parts or enhancing surface mechanical properties. However, the numerical simulation of the multi-material WLAM process presents significant challenges due to the differences in the thermophysical properties of different metals. To address this challenge, we present a predictive multi-physics solver developed within the OpenFOAM software based on the volume-of-fluid (VOF) method. The solver considers the conservation of momentum, energy, and mass, the mixture of multiple material, ray-tracing, and heat exchange with air to simulate the multi-material WLAM process. Finally, the proposed model has been validated against the numerical reference and experimental results, the comparisons show the proposed model is capable of predicting the bead geometry for different process parameters without calibration of the heat source or mass addition.