标题： SPEA -- 缺陷相图的分析热力学模型 显示英文标题

标题： SPEA -- an analytical thermodynamic model for defect phase diagram

摘要： 我们提出了一种解析热力学模型，用于描述缺陷相变，我们将其称为统计相评估方法（SPEA）。 SPEA模型假设有限尺寸相分数服从玻尔兹曼分布，并计算其统计平均值。 为了评估该模型的性能，我们将它应用于构建金属合金的二元表面相图。 考虑了两种合金体系：一种是镁表面的钙取代体系，另一种是镍表面的铌取代体系。 为了建立一个坚实的基础，以便对解析模型的性能进行比较，我们首先进行蒙特卡罗（MC）模拟，并结合密度泛函理论数据集的团簇展开。 然后，我们展示了SPEA模型能够准确再现MC结果。 具体而言，它正确预测了表面有序-无序转变以及1/3有序相和无序相的共存。 最后，我们将SPEA方法与CALPHAD方法中常用的亚晶格模型进行了比较，以描述有序和随机溶液相及其转变。 所提出的SPEA模型为建模缺陷相变提供了一种高效的方法。 显示英文摘要

摘要： We propose an analytical thermodynamic model for describing defect phase transformations, which we term the statistical phase evaluation approach (SPEA). The SPEA model assumes a Boltzmann distribution of finite size phase fractions and calculates their statistical average. To benchmark the performance of the model, we apply it to construct binary surface phase diagrams of metal alloys. Two alloy systems are considered: a Mg surface with Ca substitutions and a Ni surface with Nb substitutions. To construct a firm basis against which the performance of the analytical model can be leveled, we first perform Monte Carlo (MC) simulations coupled with cluster expansion of density functional theory dataset. We then demonstrate the SPEA model to reproduce the MC results accurately. Specifically, it correctly predicts the surface order-disorder transitions as well as the coexistence of the 1/3 ordered phase and the disordered phase. Finally, we compare the SPEA method to the sublattice model commonly used in the CALPHAD approach to describe ordered and random solution phases and their transitions. The proposed SPEA model provides a highly efficient approach for modeling defect phase transformations.