Channel segregation during solidification and the effects of an alternating traveling magnetic field

• Published in: Metallurgical and materials transactions. B, Process metallurgy and materials processing science Vol. 35; no. 4; pp. 743 - 754
• Main Authors: MEDINA, M, DU TERRAIL, Y, DURAND, F, FAUTRELLE, Y
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01.08.2004; Springer Nature B.V
• Subjects: Alloy solidification; Buoyancy; Cross-disciplinary physics: materials science; rheology; Electromagnetism; Exact sciences and technology; Magnetic fields; Materials science; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Pressure; Solidification; Lead base alloys; Segregation; Magnetic field effects; Theoretical study; Boundary conditions; Two dimensional model; Solutes; Solidification; Binary alloys; Tin alloys; Electromagnetic stirring; Modelling; Microstructure
• ISSN: 1073-5615; 1543-1916
• DOI: 10.1007/s11663-004-0014-8

The model proposed by Felicelli, Heinrich, and Poirier is used to simulate the solidification of a small two-dimensional domain of Pb-10 wt pct Sn alloy in the presence of electromagnetic stirring by different traveling fields, with or without gravity. Results show (a) enrichment of the bulk liquid by mush solute draining; (b) spontaneous formation of vertical channels, acting as ducts, significantly modified by the electromagnetic flow; and possibly (c) a finer periodic structure of subchannels. Only the last feature is sensitive to the mesh size and permeability value. Scaling analysis is used to balance Darcy, buoyancy, and electromagnetic phenomena. Attention is focused on the gradient zone at the solidification front. Electromagnetic forces can change the flow structure in the bulk liquid. In this way, they modify the pressure differences at the solidification front, changing the channel segregation pattern. Although they cannot eliminate the channels, they can control their positions and partly prevent the unsteadiness of buoyancy effects. [PUBLICATION ABSTRACT]