Interstitial solid solutions, such as carbon in steels or hydrogen in metal and alloys, are important materials for many applications. Thermodynamic models that accurately predict the behavior of interstitial solid solutions are essential for designing new materials and to improve computational materials tools. In this work, we revisited the problem of calculating the configurational entropy of interstitial solid solutions when site blocking effect occurs. Using an unprecedented approach, we propose a new site blocking model that uses the Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation to calculate the fraction of blocked sites. Since the occupation of interstitial sites in solid solutions is random, the blocking of neighbor sites can also be assumed to be random. Thus, the blocking site effect can be described as a Poisson process and the JMAK equation can be derived from Poisson statistics. The proposed model (to be called JMAK model) allows to estimate the number of blocked sites considering the site blocking overlapping phenomenon in a simple and direct way. The JMAK model was validated by comparing the calculated values of configurational entropy with both numerical simulation and experimental data.

中文翻译：

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Johnson–Mehl–Avrami–Kolmogorov 模型应用于描述间隙固溶体中的位点阻塞效应

间隙固溶体，例如钢中的碳或金属和合金中的氢，是许多应用的重要材料。准确预测间隙固溶体行为的热力学模型对于设计新材料和改进计算材料工具至关重要。在这项工作中，我们重新讨论了位点阻塞效应发生时计算间隙固溶体构型熵的问题。我们采用前所未有的方法，提出了一种新的站点封锁模型，该模型使用 Johnson–Mehl–Avrami–Kolmogorov (JMAK) 方程来计算被封锁站点的比例。由于固溶体中间隙位置的占据是随机的，因此相邻位置的阻挡也可以假设是随机的。因此，阻塞位点效应可以描述为泊松过程，并且JMAK方程可以从泊松统计中导出。所提出的模型（称为 JMAK 模型）允许以简单直接的方式考虑站点阻塞重叠现象来估计被阻塞站点的数量。通过将构型熵的计算值与数值模拟和实验数据进行比较，验证了 JMAK 模型。