Microstructure evolution of magnetic aligned MnBi phase in Bi-Mn alloys solidified in high static ma

Bi-Mn alloys were prepared under three different solidification conditions respectively. The microstructure evolutions of magnetic aligned MnBi grains were investigated experimentally in dependence on magnetic flux density and solidified time. The results show that, solidifying from mushy zone between 265℃ and 355℃ in an 1.0T magnetic field, the aligned rod-like MnBi grains congregate and grow up along the direction of magnetic field with the increase of solidified time so that the mean ratio of long axis to diameter of the grains increases about 50%; solidifying from mushy zone between 355℃ and 446℃, the aligned oblate-shaped MnBi grains also congregate and grow up along the direction of magnetic field with the increase of magnetic flux density (up to 10.0T) and solidified time, while several huge rod-like MnBi grains appear, which are irregular and loose; solidifying from molten state, the textured structure of MnBi phase can form at a cooling rate of 0.15℃/s, but can not at 0.015℃/s or slower. The remanence of Bi-Mn alloys can hardly be enhanced by prolongating solidified time in a magnetic field.