Alignment behavior of the primary Al_3Ni phase in Al- Ni alloy under a high magnetic field

摘要

Influences of a high magnetic field on the alignment behavior of the primary Al_3Ni phase in three hypereutectic Al-Ni alloys have been investigated and the results show that the plane alignment perpendicular to the magnetic field has formed under a certain condition. The alignment-influencing factors have been investigated and it is found that the magnetic field intensity, solidification temperature and the alloy composition have played great roles during the alignment process. Indeed, it is observed that under a certain magnetic field intensity there exists a critical solidification temperature, and above this temperature the alignment degree increases with the increase of the solidification temperature, and that under a certain solidification temperature there exists a critical magnetic field intensity, and above this magnetic field intensity the alignment degree increases with the increase of the magnetic field intensity. It has also been found that with the increase in the Ni content of the alloy the alignment degree decreases. By means of XRD and EBSD analysis, the crystal orientation has studied and results show that the < 001 > crystal direction of the Al_3Ni crystal orients along the magnetic field and the <100>, <110> and <010> crystal directions align perpendicular to the magnetic field. This is discussed based on the magnetocrystalline anisotropy of the Al_3Ni crystal and the rotating alignment of the primary phase under a high magnetic field.