Influence of High Magnetic Field on Peritectic Transformation during Solidification of Bi-Mn Alloy

摘要

The influence of high magnetic field up to 10T on peritectic temperature of Bi-Mn alloys have been investigated experimentally. A method for measuring the peritectic temperature in a gradient magnetic field has been put out based on the change of magnetic levitation force which is. related to the phase transformation of the alloy due to the change in magnetic susceptibility while the transformation occur. By measuring the temperature at which the magnetizing force change abruptly, the phase transformation was detected. It is shown that along with increase of magnetic filed, the temperature of phase transformation BiMn1.08 + L BiMn increased significantly, and in a 10T field the temperature increased about 20℃ . It is found that with the high magnetic field in the peritectic transformation, split and separation of the BiMn grains on the direction perpendicular to the magnetic field occurred, and the peritectic phase BiMn became small blocks instead of leaf-like grain. This is attributed to the repulsive force among the peritectic BiMn grains generated due to the magnetization during the phase transformation. It seems that the precipitation of ferromagnetic phase during phase transformation will result in stress in the grains.