Grain Refinement Induced by a Pulsed Magnetic Field and Synchronous Solidification

Abstract

An experimental study on the influence of a pulsed magnetic field (PMF) on the unidirectional solidification of pure aluminum is reported. The forced convection induced by PMF encourages a thermal homogenization of the liquid zone ahead of the solidification front. Meanwhile, synchronous solidification occurs under high magnetic intensity to form fine equiaxed grains in the entire ingot. The solidification time exhibits a trend of going from initial ascent to subsequent decent with increasing magnetic intensity. Finally, the solidification times of various temperature measurement points in the casting approach a convergence point at a magnetic intensity of 0.154 T, at which the finest grain size appears in the ingots. A thermodynamic expression with the application of PMF is discussed.

Keywords:

• Grain refinement
• Pulsed magnetic field
• Pure aluminum
• Solidification time

ACKNOWLEDGMENTS

The authors are grateful to the National Natural Science Foundation of China for the financial support that it provided through Project No. 50874093 and No. 51054007. Likewise, the authors would like to express their appreciation to a former graduate student of Tao Jiandong for his contribution to the experimental work.