Influence of high magnetic field on peritectic transformation during solidification of Bi–Mn alloy

Abstract

The influence of high magnetic fields up to 10 T on the peritectic temperature of Bi–Mn alloys has been investigated experimentally. A method for measuring the peritectic temperature in a gradient magnetic field has been developed by relating the change of magnetic levitation force to the phase transformation due to the change in magnetic susceptibility while the transformation occurs. By measuring the temperature at which the magnetizing force changes abruptly, the phase transformation can be detected. It is shown that along with the increase of magnetic field, the temperature of the peritectic phase transformation BiMn 1.08+ L→BiMn increased significantly, and in a 10 T field the temperature increase was about 20 ∘C. It is found that with the high magnetic field, a split and separation of the BiMn grains in the direction perpendicular to the magnetic field occurred, and its morphology changed from flakes to small blocks. This is attributed to the repulsive force among the peritectic BiMn grains generated by the magnetization during the phase transformation. It seems that the precipitation of ferromagnetic phase results in stress in the grains.