A synchrotron X-ray radiography study of dendrite fragmentation induced by a pulsed electromagnetic field in an Al–15Cu alloy
2014; Elsevier BV; Volume: 70; Linguagem: Inglês
10.1016/j.actamat.2014.02.024
ISSN1873-2453
AutoresEnzo Liotti, Andrew Lui, Robin Vincent, S. Kumar, Zhengxiao Guo, Thomas Connolley, Igor P. Dolbnya, Michael Hart, L. Arnberg, Ragnvald H. Mathiesen, Patrick S. Grant,
Tópico(s)Metallurgical Processes and Thermodynamics
ResumoAn in situ technique for studying the effect of a pulsed electromagnetic field on dendrite fragmentation behavior based on synchrotron X-ray imaging has been developed, involving the passage of an oscillating current through a foil specimen placed in a static magnetic field. In all cases, the application of a pulsed electromagnetic field to an array of Al–15 wt.%Cu dendrites led to an increase in dendrite fragmentation rate. The induced movement of inter-dendritic liquid between the primary and secondary dendrite arms even at high solid fraction led to instabilities in the local temperature–concentration–curvature equilibrium and the rapid remelting of the most vulnerable microregions. The new in situ methodology provides a basis for the optimization of pulsed electromagnetic field parameters to enhance grain refining performance for specific alloys and casting conditions.
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