Solidification microstructure and thermodynamic calculation of the Sm-Co-Ti ternary system

Solidification microstructure and phase equilibria of the Sm-Co-Ti ternary system were investigated through experimental study and thermodynamic calculation. The solidification microstructure of several Sm-Co-Ti as-cast alloys was investigated experimentally by electron probe microanalysis (EPMA). Based on the experimental data from this work and the literature, thermodynamic calculation of the Sm-Co-Ti ternary system was performed using the CALPHAD method together with the prior assessments of the Sm-Co, Co-Ti and Sm-Ti binary systems. The calculated isothermal section and liquidus projection for this ternary system demonstrate the good agreement with the reported experimental data. Solidification microstructure of Sm-Co-Ti alloys was analyzed through thermodynamic calculation using the Scheil-Gulliver non-equilibrium model. The excellent agreement between the simulated results and experimental observations indicates that thermodynamic parameters of the Sm-Co-Ti ternary system obtained in this work are reasonable, which would provide a critical foundation for developing a reliable thermodynamic database of multicomponent Sm-Co-based permanent magnets with transition metals.