Thermodynamic assessment for the Bi-Mn binary phase diagram in high magnetic fields

The thermodynamic calculations of the Bi-Mn binary phase diagram in high magnetic fields are carried out by the Computer Coupling of Phase Diagrams (CALPHAD) method. The magnetic total energy Emag was estimated by calculating magnetization on the basis of the mean field theory. The calculated results show the significant change of the Bi-Mn phase diagram under magnetic fields, which were in good agreement with the experimental results of in-field thermal analysis performed by Mitsui et al. The calculation shows that the peritectic temperature Tp1 (BiMn + liquid → BiMn1.08 + liquid) reached another peritectic temperature Tp2 (BiMn1.08 + liquid → Mn + liquid) at 49 T, suggesting that BiMn will form directly from Mn + liquid without forming BiMn1.08 by the heat treatment in B ⩾ 49 T.