The effects of thermo-electrically induced convection in alloy solidification

A. Kao, K. Pericleous, M. Patel, V. Voller

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

The effects of a constant uniform magnetic field on thermoelectric currents during dendritic solidification were investigated using a 2-dimensional enthalpy based numerical model. Using an approximation of the dendrite growing in free space it was found that the resulting Lorentz force generates a circulating flow influencing the solidification pattern. As the magnetic field strength increases it was found that secondary growth on the clockwise side of the primary arm of the dendrite was encouraged, while the anticlockwise side is suppressed due to a reduction in local free energy. The preferred direction of growth rotated in the clockwise sense under an anti-clockwise flow for both the binary alloy and pure material. The tip velocity is significantly increased compared to growth in stagnant flow. This is due to a small recirculation that follows the tip of the dendrite; bringing in colder liquid and lower concentrations of solute. The recirculation being not normally incident on the tip is most likely the cause for the rotation. Grain growth consisting of multiple seeds with the same anisotropy growing in the same plane, gives a competition to release latent heat resulting in stunted growth. The initial growth for each dendrite is very similar to the single seed cases indicating that dendrites must become close before the thermoelectric interactions are significant.

Original languageEnglish (US)
Title of host publicationProceedings of the 6th International Conference on Engineering Computational Technology
StatePublished - Dec 1 2008
Event6th International Conference on Engineering Computational Technology, ECT 2008 - Athens, Greece
Duration: Sep 2 2008Sep 5 2008

Publication series

NameProceedings of the 6th International Conference on Engineering Computational Technology

Other

Other6th International Conference on Engineering Computational Technology, ECT 2008
CountryGreece
CityAthens
Period9/2/089/5/08

Keywords

  • Binaryalloy
  • Dendritic-growth
  • Enthalpy
  • MHD
  • Thermoelectricity
  • Undercooling

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  • Cite this

    Kao, A., Pericleous, K., Patel, M., & Voller, V. (2008). The effects of thermo-electrically induced convection in alloy solidification. In Proceedings of the 6th International Conference on Engineering Computational Technology (Proceedings of the 6th International Conference on Engineering Computational Technology).