Effect of static magnetic field on the molten pool dynamics during laser powder bed fusion of Inconel 718 superalloy

Recent researches show that a static magnetic field (SMF) has an impact on the molten pool dynamics and microstructure of laser powder bed fusion (L-PBF). This work is intended to the multiple effect of SMF on the molten pool dynamics during L-PBF of Inconel 718 superalloy. A three-dimensional (3D) multiphase computational fluid dynamics (CFD) model at the powder-bed scale was established by coupling the electromagnetic braking and Seebeck effect in a static vertically-distributed magnetic field. Results show that the magnetic damping force (MDF) of the order of 104 N/m3-105 N/m3 within the whole molten pool suppresses the Marangoni convection. The thermoelectric magnetic force (TEMF) of the order of 106 N/m3-107 N/m3 rotates in the mushy zone and further enhances the melt flow of the whole molten pool. The SMF will not transform the flow pattern and temperature distribution in the molten pool. SMFs of 0.1 T and 0.3 T will suppress the melt flow, while that of 0.5 T will enhance the melt flow. The width of molten pool first decreases and then increases when the magnetic flux density (MFD) increases from 0 T to 0.5 T. In addition, applying a SMF of 0.3 T can effectively inhibit pore defect and spatters. This work can provide insight into the control of molten pool by introducing a SMF during L-PBF.