Molten Pool Dynamics and Particle Migration Behavior during TIG-assisted Droplet Deposition Manufacturing of SiC Particle-reinforced Aluminum Matrix Composites

Abstract：A transient three-dimensional (3D) numerical model based on computational fluid dynamics is developed to simulate the molten pool behaviors during the tungsten inert gas (TIG) welding arc-assisted droplet deposition manufacturing (DDM) of silicon carbide (SiC) particle-reinforced aluminum matrix composites (AMCs).The factors, such as arc forces, the interaction between SiC particles and liquid Al matrix, and surface tension, are considered in the model.The model was validated by comparing the simulation data and results obtained from DDM on the cross-sectional profile and particle distribution of deposits.The evolution law of the peak temperature in molten pool is discussed, the impact-induced molten pool characteristics and the migration behaviors of SiC particles are investigated.The results showed that the TIG-assisted DDM process can be broken down into four phases, including droplet impacting, coalescing, spreading and recoiling.The remelting is observed near the impacting point, a V-shaped depression is formed at the molten pool center, a crown-like hump is generated at the edge of the molten pool.Most of the reinforcements are deposited at the both sides of deposits due to the melt's dragging force.The deposition of the reinforcements toward the bottom of the molten pool is suppressed by the impact-induced local elevated pressure and the convection within the molten pool.