Kao, A. ORCID: 0000-0002-6430-2134 , Gan, T., Tonry, C. ORCID: 0000-0002-8214-0845 , Krastins, I. and Pericleous, K. ORCID: 0000-0002-7426-9999 (2020) Thermoelectric magnetohydrodynamic control of melt pool dynamics and microstructure evolution in additive manufacturing. Philosophical Transactions of The Royal Society A: Mathematical, Physical and Engineering Sciences, 378 (2171). ISSN 1364-503X (Print), 1471-2962 (Online) (doi:https://doi.org/10.1098/rsta.2019.0249)

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Abstract

Large thermal gradients in the melt pool from rapid heating followed by rapid cooling in metal additive manufacturing generate large thermoelectric currents. Applying an external magnetic field to the process introduces fluid flow through thermoelectric magnetohydrodynamics. Convective transport of heat and mass can then modify the melt pool dynamics and alter microstructural evolution. As a novel technique, this shows great promise in controlling the process to improve quality and mitigate defect formation. However, there is very little knowledge within the scientific community on the fundamental principles of this physical phenomenon to support practical implementation. To address this multiphysics problem that couples the key phenomena of melting/solidification, electromagnetism, hydrodynamics, heat and mass transport, the lattice Boltzmann method for fluid dynamics was combined with a purpose-built code addressing solidification modelling and electromagnetics. The theoretical study presented here investigates the hydrodynamic mechanisms introduced by the magnetic field. The resulting steady-state solutions of modified melt pool shapes and thermal fields are then used to predict the microstructure evolution using a cellular automata based grain growth model. The results clearly demonstrate that the hydrodynamic mechanisms and, therefore, microstructure characteristics are strongly dependent on magnetic field orientation.

Item Type:	Article
Additional Information:	© 2020 The Author(s).
Uncontrolled Keywords:	thermoelectric magnetohydrodynamics, additive manufacturing, melt pool dynamics, microstructure
Subjects:	Q Science > QA Mathematics > QA75 Electronic computers. Computer science
Faculty / School / Research Centre / Research Group:	Faculty of Engineering & Science > Centre for Numerical Modelling & Process Analysis (CNMPA) Faculty of Engineering & Science > Centre for Numerical Modelling & Process Analysis (CNMPA) > Computational Science & Engineering Group (CSEG) Faculty of Engineering & Science > School of Computing & Mathematical Sciences (CMS) Faculty of Engineering & Science
Related URLs:	Publisher
Last Modified:	04 Mar 2022 13:06
URI:	http://gala.gre.ac.uk/id/eprint/27743

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