Thermoelectric magnetohydrodynamic control of melt pool flow during laser directed energy deposition additive manufacturing

DOI: 10.1016/j.addma.2023.103587

Authors: Xianqiang Fan (University College London (UCL)) , Tristan G. Fleming (Queen's University) , David T. Rees (University College London; Research Complex at Harwell) , Yuze Huang (Coventry University) , Sebastian Marussi (University College London; Research Complex at Harwell) , Chu Lun Alex Leung (University College London; Research Complex at Harwell) , Robert C. Atwood (Diamond Light Source) , Andrew Kao (University of Greenwich) , Peter D. Lee (University College London; Research Complex at Harwell)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Additive Manufacturing , VOL 71

State: Published (Approved)
Published: June 2023
Diamond Proposal Number(s): 28804

Abstract: Melt flow is critical to build quality during additive manufacturing (AM). When an external magnetic field is applied, it causes forces that alter the flow through the thermoelectric magnetohydrodynamic (TEMHD) effect, potentially altering the final microstructure. However, the extent of TEMHD forces and their underlying mechanisms, remain unclear. We trace the flow of tungsten particles using in situ high-speed synchrotron X-ray radiography and ex situ tomography to reveal the structure of TEMHD-induced flow during directed energy deposition AM (DED-AM). When no magnetic field is imposed, Marangoni convection dominates the flow, leading to a relatively even particle distribution. With a magnetic field parallel to the scan direction, TEMHD flow is induced, circulating in the cross-sectional plane, causing particle segregation to the bottom and side of the pool. Further, a downward magnetic field causes horizontal circulation, segregating particles to the other side. Our results demonstrate that TEMHD can disrupt melt pool flow during DED-AM.

Journal Keywords: Additive manufacturing; Melt flow control; Thermoelectric magnetohydrodynamic; Magnetic fields; Tungsten tracer

Diamond Keywords: Additive Manufacturing

Subject Areas: Materials, Engineering


Instruments: I12-JEEP: Joint Engineering, Environmental and Processing

Added On: 10/05/2023 09:56

Documents:
1-s2.0-S2214860423002002-main.pdf

Discipline Tags:

Materials Engineering & Processes Materials Science Engineering & Technology

Technical Tags:

Imaging Tomography