The calorimetry method was employed to determine the mixing enthalpies of Gd–Sn melts and the ideal associated solution (IAS) model to calculate and optimize the thermodynamic properties of Gd–Sn alloys at 1510, 1640, and 1873 K in the composition range 0 ≤ x_Sn ≤ 1.0. The minimum mixing enthalpies were –69.7 ± 0.6 kJ/mole (1873 K) and –77.9 ± 0.7 (1510 K) kJ/mole at x_Sn = = 0.45. Using our own and published data on the thermochemical properties of melts and compounds and assuming the formation of two associates in the melt, Gd₂Sn and GdSn, we calculated the activities of components, enthalpies, Gibbs energies, and entropies of formation for the liquid alloys and intermediate phases within the IAS model. The thermodynamic activities of components in the studied melts showed very large negative deviations from the ideal solutions. The mixing enthalpies of Sn–Gd melts optimized within the IAS model agreed well with the experimental values. The \( \Delta {\overline{H}}_{\mathrm{Gd}}^{\infty } \) temperature dependence agrees only qualitatively with other experimental data because of great errors in the published data. The excess Gibbs energy and mixing enthalpy of Gd–Sn melts calculated with the IAS model at 1873 K greatly differed in magnitude, being indicative of a significant contribution of the entropy component to the excess molar Gibbs energy. According to the calculations, the minimum excess mixing entropy for Gd–Sn melts at 1873 K was –20.3 J/(mole · K) at x_Sn = 0.45. The calculated and optimized enthalpies and entropies of formation for intermetallic phases in the Gd–Sn system, along with the IAS model parameters for melts, were used to calculate the liquidus and solidus curves of the phase diagram. Good agreement with most experimental data on the phase equilibria involving liquid and crystalline phases was shown.

采用量热法确定 Gd-Sn 熔体的混合焓和理想相关溶液 (IAS) 模型，以计算和优化 Gd-Sn 合金在 1510、1640 和 1873 K 时的热力学性能，成分范围 0 ≤ x_锡≤1.0。在x _Sn = = 0.45 时，最小混合焓为 –69.7 ± 0.6 kJ/mole (1873 K) 和 –77.9 ± 0.7 (1510 K) kJ/mole 。使用我们自己和已发表的关于熔体和化合物的热化学性质的数据，并假设在熔体中形成两种缔合物，Gd ₂Sn 和 GdSn，我们计算了 IAS 模型中液态合金和中间相的组分活度、焓、吉布斯能和形成熵。所研究熔体中组分的热力学活动显示出与理想溶液的非常大的负偏差。在 IAS 模型中优化的 Sn-Gd 熔体的混合焓与实验值非常吻合。的\（\德尔塔{\划线{H}} _ {\ mathrm {钆}} ^ {\ infty} \）由于公布的数据存在很大误差，因此温度依赖性仅与其他实验数据在定性上一致。使用 IAS 模型在 1873 K 计算的 Gd-Sn 熔体的过量吉布斯能量和混合焓在大小上有很大差异，这表明熵分量对过量摩尔吉布斯能量的显着贡献。根据计算，Gd-Sn 熔体在 1873 K 时的最小过量混合熵为 –20.3 J/(mole · K) at x _Sn= 0.45。计算和优化的 Gd-Sn 系统中金属间相的生成焓和熵，以及熔体的 IAS 模型参数，用于计算相图的液相线和固相线曲线。显示了与涉及液相和结晶相的相平衡的大多数实验数据的良好一致性。