Effect of pulsed magnetic field on the grain refinement and mechanical properties of 6063 aluminum alloy by direct chill casting.

Pulsed magnetic field (PMF) was successfully applied during direct chill (DC) casting of 6063 Al alloy. The effect of PMF on the solidification structure and mechanical properties was investigated. The results indicated that the coarse equiaxed grain turns into homogeneous and refined equiaxed grain under the effect of PMF, and the grain refinement effect increases with increasing the input current in the study. This can be attributed to the reduced temperature gradient in the melt and enhanced heterogeneous nucleation caused by forced convection, based on the simulation results of Lorenz force, flow field, and temperature field during DC casting under PMF. The application of PMF can also efficiently reduce the macro- and microsegregations of Mg and Si elements, which are beneficial to the uniformly dispersed precipitation of MgSi phase after T6 treatment, resulting in a significant enhancement of strength and hardness. The best mechanical properties of the 6063 Al alloy are achieved under PMF with an input current of 500 A, exhibiting the increments of 35.6% in hardness, 42.2% in ultimate tensile strength, and 30.6% in elongation, respectively. This study may offer a promising method for industrial preparation of high-quality alloys by DC casting. [ABSTRACT FROM AUTHOR]