Progress in Research on Solidification in a Strong Static Magnetic Field

Abstract

Strong magnetic fields available from superconducting magnets are opening a way to new phenomena that could lead to new methods in materials processing including solidification. The principal research involving solidification in strong static magnetic fields is emphasizing four aspects: control of crystal orientation, convection damping, thermoelectric magnetohydrodynamics (TEMHD) and change in thermodynamics. Under high magnetic intensity, aligned structural textures are induced in both magnetic and non-magnetic materials. Since in strong magnetic field the melt flow is suppressed by convection damping, the microstructure being formed during solidification is affected heavily; this phenomenon applies to eutectic, monotectic and peritectic alloys as well as to dendritic morphologies typical of directional solidification. If strength and orientation of a magnetic field are controlled appropriately, this strong damping effect will generate more homogeneous crystals as a result of achieving diffusion-controlled solute transport conditions. TEMHD more easily occurs in strong magnetic fields, resulting in equiaxed crystals even under directional solidification. It is evidenced experimentally and theoretically that the thermodynamics of phase transformation and nucleation are changed by strong magnetic fields.

Solidification of Immiscible Alloys under High Magnetic Field: A Review

“…The application of the magnetic field may increase or decrease the maximum undercooling of alloy systems. Most alloys are nonferromagnetic at solidification temperature, and the solidification undercooling under HMF can be expressed as [48] ∆T…”

“…For magnetic material, during the non-equilibrium solidification, HMF has a great influence on the solidification point. The relation between solidification point temperature and applied HMF is given by [48]. Without HMF, the phase temperature changes to T 1 .…”