Magnetic Fields, Convection and Solidification L.Hachani 1,a , J.Wang 2,b , I. Kaldre 3,c , G. Salloum Abou-Jaoude 4,d , O. Budenkova 1,e , G. Reinhart 4,f , K. Zaidat 1,g , N. Mangelinck 4,h , X. Li 2,i , H. Nguyen Thi 4,j , A. Bojarevics 3,k , Z.-M.Ren 2,l , L. Buligins 3,m , and Y. Fautrelle 1,n 1 SIMAP/EPM/Grenoble Institute of Technology/CNRS, BP 75, 38402 Saint Martin dHères Cedex, France 2 Shanghai University, 149 YanChang Road, Shanghai 200072, P.R. 3 Latvia University Riga, Institute of Physics, Salaspils, Latvia 4 Aix-Marseille Université & CNRS, IM2NP, UMR 6242 Campus Saint-Jérôme, Case 142, 13397 Marseille Cedex 20, France a lakhdar.hachani@yahoo.fr, b wangjiang417@163.com, c imyx@inbox.lv, j henri.nguyen-thi@im2np.fr, e olga.budenkova@simap.grenoble-inp.fr, g kader.zaidat@phelma.grenoble-inp.fr, i lx_net@sina.com, h nathalie.mangelinck@im2np.fr, f guillaume.reinhart@im2np.fr, d georges.salloum@im2np.fr, k andrisb@sal.lv, m Leonids.Buligins@lu.lv, l zmrenb@163.com n Yves.Fautrelle@simap.grenoble-inp.fr (corresponding author) Keywords: Solidification, natural convection, sedimentation, stratification, magnetic field, electromagnetic stirring, segregations, thermo-electric effect, thermo-electric convection Abstract. In solidification processes the fluid flow occurs almost at every scale from the bulk, near the interfaces and deeply in the mushy zone. Numerical modeling is a valuable tool for understanding and master the solidification processes, however, macro-scale models are not always able to predict in detail the random behavior of the solidification process whereas models for micro scales are not capable to take into account a complex structure of flows which enter into the mushy zone. In the present paper the variety of the flows and imprints they left on solidification structure are discussed and illustrated with experimental data which naturally comprise every flow occurring in the process. Introduction Mastering of the solidification is one of the main targets in process metallurgy. Mastering encompasses elimination of the various defects as well as control of the solidified structures. Liquid metal flows existing both in the bulk and in the mushy zone are one of the key parameters regarding the control of solidification. Convection is responsible for various kinds of phenomena, like macro/meso-segregations, re-melting, dendrite fragmentation and promotion of equiaxed structures [1]. Fluid flows may be generated by various types of body forces or sometimes surface stresses like thermo-capillary effects. The most usual forces are caused by gravity, polyphase magnetic fields or magneto-thermo-electric effects. Except in micro-gravity conditions, natural convection is present in almost all solidification devices. Rotating or travelling magnetic fields are commonly used in solidification in order to stir the liquid bulk or to create fragments. Opposite to them, the static magnetic field is used to decrease the level of fluid flows for example in order to eliminate natural convection in crystal growth [2-4] or to control flows at the outlet of nozzles in steel continuous casting [5]. It has been demonstrated that by means of intense static fields it is also possible to produce crystal alignment, texturation of structures or phase sedimentation [6-7], however, it was realized quite recently that static magnetic fields may interact with thermo-electric current and produces flows, the so-called magneto-thermo-electric currents. Complete suppression of any flow requires intense fields, almost 20 T and some examples demonstrate that effect. Materials Science Forum Vols. 790-791 (2014) pp 375-383 Online available since 2014/May/09 at www.scientific.net © (2014) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/MSF.790-791.375 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 147.94.134.4-21/05/14,09:06:33)