TIG电弧辅助熔滴沉积增材制造SiCp增强铝基复合材料中的熔池动力学与颗粒迁移行为

基于计算流体力学方法，考虑电弧力、碳化硅颗粒(SiC_p)增强相与液态铝合金基体相之间的相互作用以及表面张力等因素，建立了Si C_p增强铝基复合材料钨极氩弧焊(TIG)电弧辅助熔滴沉积增材制造中的三维瞬态熔池行为数值模型，通过与堆积试样的横截面形貌、Si C_p分散状态实验结果对比，验证了熔池行为数值模型的有效性。通过数值模拟，揭示了堆积过程熔池峰值温度演变规律、熔滴冲击诱导的熔池动力学行为、熔池流态对Si C颗粒迁移行为的影响。结果表明，堆积过程涉及熔滴冲击、合并、铺展、熔池回弹4个阶段；冲击点附近出现重熔，熔滴冲击造成熔池中心区域产生明显的V字形凹陷，熔池边缘形成冠状隆起；在熔体拖拽力的作用下Si C颗粒更多的分布于堆积层两侧；熔滴冲击引起的熔池内局部高压以及熔池底部对流，抑制了Si C颗粒向熔池底部沉降。

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

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.