Variety of solidification structures in Al-2.89%Fe alloy solidified under high magnetic field

The morphology and distribution of Al3Fe phase in hypereutectic Al-2.89%Fe alloy solidified under high magnetic field was investigated.The effects of cooling rate, magnetic intensity and high gradient magnetic field on the distribution of Al3Fe were studied. The results showed that the primary Al3Fe phase with needle-like morphology was gathered at the bottom of the sample due to the gravity force when the alloy was solidified without the high magnetic field. However, when the high magnetic field of 12T was applied, the primary Al3Fe phase distributed throughout the sample homogeneously because that the magnetic force acted on the primary Al3Fe phase balanced with the gravity force, and the primary Al3Fe phase aligned perpendicularly to the magnetic field direction with a preferred direction 121]. Its orientation extent was not affected by cooling rate, but strengthened with increasing magnetic intensity. When the sample was set at the position with a large positive gradient magnetic field, the magnetic force acted on the primary Al3Fe phase was greater than the gravity force, resulting in their segregation to the upper portion of the sample. Several needle-like primary Al3Fe phases were integrated to form the polymer with a star shape. Furthermore, the mechanism of high magnetic field was discussed.