Abstract Phase diagram calculation of Fe–Ti system is obtained by coupling of CALPHAD with first principle methods. Single Gibbs energy model is used for FeTi to take care of order-disorder transition. First principle calculation shows that Laves phase is ferromagnetic nature with the magnetic moment of 1.417 μ B which is incorporated in the modelling. For extrapolation to higher order system, Laves phase is mostly expressed with two sublattice model. From crystallographic view, 3 sublattice model is appropriate one for description of Laves phase. Hence, two different models are used for Laves phase. Wagner-Schottky model used to describe the homogeneity region of Laves phase in two sublattice model. Using the first principle method, the energies of formation of unstable end members of FeTi phase and three sublattice model of Laves phase are calculated and incorporated as experimental data in optimisation. Calculated phase diagram and the thermochemical properties using 3 sublattice model of Laves phase shows good agreement with the experimental data.

中文翻译：

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使用第一性原理方法对 Fe-Ti 系统中的磁熔体相进行热力学模拟

摘要 通过CALPHAD与第一性原理方法的耦合，得到了Fe-Ti体系的相图计算。FeTi 使用单吉布斯能量模型来处理有序-无序转换。第一原理计算表明，Laves 相具有铁磁性质，具​​有 1.417 μ B 的磁矩，并包含在建模中。对于高阶系统的外推，Laves 相位主要用两个亚晶格模型表示。从晶体学的角度来看，3 亚晶格模型是描述 Laves 相的合适模型。因此，Laves 阶段使用了两种不同的模型。Wagner-Schottky 模型用于描述两个亚晶格模型中 Laves 相的均匀区域。使用第一原理方法，计算了 FeTi 相不稳定端元的形成能量和 Laves 相的三个亚晶格模型，并将其作为实验数据纳入优化。使用Laves相的3个亚晶格模型计算的相图和热化学性质与实验数据显示出良好的一致性。