Numerical simulation of molten pool-particle behavior in magnetic field-assisted laser welding of SiCp/Al composites

Magnetic field-assisted welding is a widely utilized technique that effectively controls the flow of the molten pool and reduces particle phase agglomeration in the welding of SiCp/Al matrix composites. Despite its advantages, challenges related to process monitoring and a lack of clarity regarding the underlying mechanisms have hindered its broader application. This study investigates molten pool flow dynamics and SiCp particle distribution through simulations of magnetic field-assisted welding for SiCp/Al matrix composites. Without the magnetic field, two primary circulations are observed in the molten pool, where particle inertia drives particles toward the outer regions of the circulations. Particles also cluster and deposit in low-velocity regions at the circulation junctions. In contrast, during magnetic field-assisted laser welding, the Seebeck effect between the particles and the magnetic field induces a thermal current, generating significant perturbations near the fusion line and around the keyhole. These perturbations promote a more uniform particle distribution, improving particle homogeneity by similar to 13 % and similar to 10 % under transverse and longitudinal magnetic fields, respectively. Additionally, the magnetic field reduces the velocity in the molten pool's central region by approximately 40 %, leading to a more stabilized Marangoni flow. This work provides both theoretical insights and practical approaches to address SiC particle agglomeration in laser welding of metal matrix composites.