EBSD study of the morphology and orientation of the primary and eutectic phases in Al–Cu alloys during solidification under a strong magnetic field

Abstract

The effect of a strong magnetic field on the morphology and orientation of the Al2Cu dendrite and Al–Al2Cu eutectic in Al–Cu alloys was studied using electron backscatter diffraction (EBSD) technology. The experimental results revealed that the applied magnetic field modified the morphology and orientation of both the Al2Cu dendrite and the Al–Al2Cu eutectic significantly. The magnetic field caused a break in the Al2Cu dendrite and the degeneration of Al–Al2Cu eutectic lamellae during directional solidification. It was also found that the magnetic field caused the formation of dislocations in the α-Al and Al2Cu phases during directional solidification. In addition, the primary and eutectic Al2Cu phases were oriented with the 〈001〉 crystal direction along the magnetic field during volume solidification. Both α-Al and Al2Cu phases were oriented with the 〈001〉 crystal direction along the solidification direction during directional solidification under an axial magnetic field. The above phenomena were enhanced as the magnetic field increased; this could be attributed to magnetic crystalline anisotropy of the material and thermoelectric magnetic effects. This study may offer experimental evidence that shows that thermoelectric magnetic effects significantly influence dendrite arrays during directional solidification in a magnetic field.