A synchrotron X-ray radiography study of dendrite fragmentation induced by a pulsed electromagnetic field in an A1-15Cu alloy

Journal article

An 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. Crown Copyright © 2014 Published by Elsevier Ltd. on behalf of Acta Materialia Inc. All rights reserved.

Authors: Liotti, E; Lui, A; Vincent, R; Kumar, S; Guo, Z

• Publication status: Published
• Journal: ACTA MATERIALIA
• Volume: 70
• Pages: 228-239
• Publication date: 2014-05-15
• DOI: 10.1016/j.actamat.2014.02.024
• ISSN: 1359-6454
• Keywords: Dendrites fragmentation; Solidification; Synchrotron X-ray radiography; Aluminum alloys; Electromagnetic field