Thermodynamic properties and thermodynamic assessment of Ta-Sn system

摘要

For the little thermodynamic information of Ta-Sn system, the liquid mixing enthalpy of Ta-Sn system, and the formation enthalpy of Ta_2Sn_3 and Ta_3Sn were calculated by Miedema model. The Ta-Sn phase diagram was modeled using CALPHAD technology to obtain a reliable thermodynamic description of the system. Two intermetallic compounds Ta_2Sn and Ta_3Sn were treated as stoichiometric compounds for the very narrow homogeneity ranges. The higher temperature phase diagram of Ta-Sn system was constructed according to Nb-Sn system for the empty information. The optimization process was carried out using the PARRAT software including in Thermo-Calc database system. The thermodynamic calculated Ta-Sn phase diagram is agreement with the evaluated phase diagram, and the calculated mixing enthalpies of molten Ta-Sn system match well with the Miedema data. The formation enthalpies of the two intermetallic compounds Ta_2Sn and Ta_3Sn are compared with the Miedema values.