@article{discovery10205876,
           pages = {864--869},
           title = {Magnetic modulation of keyhole instability during laser welding and additive manufacturing},
          volume = {387},
            note = {This version is the author accepted manuscript. For information on re-use, please refer to the publisher's terms and conditions.},
       publisher = {American Association for the Advancement of Science (AAAS)},
         journal = {Science},
           month = {February},
          number = {6736},
            year = {2025},
            issn = {0036-8075},
             url = {https://doi.org/10.1126/science.ado8554},
        abstract = {Keyhole instability during laser welding and laser powder bed fusion (LPBF) can cause keyhole collapse and pore formation. Using high-speed x-ray imaging, we demonstrate that the flow vortex-induced protrusion on the rear keyhole wall is crucial in initiating keyhole instability. Applying a transverse magnetic field suppresses the keyhole instability by driving a secondary thermoelectric magnetohydrodynamics (TEMHD) flow that alters the net flow vortex. This minimizes protrusions and large-amplitude keyhole oscillations. The suppression effectiveness depends on the laser scanning direction relative to the magnetic field orientation because this controls the Seebeck effect-induced Lorentz force's direction. We show that at LPBF length scales, electromagnetic damping is weak, and for alloys with a large Seebeck coefficient, TEMHD becomes the dominant mechanism controlling flow behind the keyhole.},
          author = {Fan, Xianqiang and Fleming, Tristan G and Clark, Samuel J and Fezzaa, Kamel and Getley, Anna CM and Marussi, Sebastian and Wang, Hongze and Leung, Chu Lun Alex and Kao, Andrew and Lee, Peter D}
}