GRAIN REFINEMENT OF PURE ALUMINUM UNDER EXTERNAL ELECTROMAGNETIC FIELD TREATMENT - REVIEWS AND NEW EXPERIMENTAL EVIDENCE

摘要

This paper summarized the previous investigations about the grain refinement of pure aluminum under electromagnetic field (EMF) treatment, including electric current pulse (ECP), pulse magnetic field (PMF), pulsed magneto-oscillation (PMO) and surface pulsed magneto-oscillation (SPMO). Our previous researches mainly considered the exerting-modes, the effective acting stage and the origination of crystal nuclei for grain refinement of EMF. Moreover, the nucleation and grain formation under PMO treatment was experimentally examined simultaneously, and it was found that the temperature field during the solidification of the melt also has an important influence on the grain refinement. The more uniform temperature field in the melt, the bigger fraction of equiaxed grains can be obtained. This paper contributes to well understand the grain refinement mechanism of EMF.