Dendrite morphology in Al-20 wt%Cu hypoeutectic alloys in 24 T high magnetic field quantified by ex-situ X-ray tomography

The morphology of the primary α-Al crystal in a solidifying Al-20 wt%Cu alloy under the high static magnetic field (HMSF) was studied by using the ex-situ X-ray computed tomography technique. The side arms were the seaweed and the dendrite under 0 T and 24 T HSMF, respectively. They were identified by 2D slices and 3D reconstruction of dendrites. The secondary dendrite arm spacing increased and the interface curvatures decreased under the HSMF. The growth angle between the secondary dendrite arms and their stems was close to 90° in the case of the 24 T HSMF. These were attributed to the decrease of constitutional supercooling caused by magnetohydrodynamic effect.