The main goal of the study is to introduce a two-nearest-neighbor structure model for analyzing low-expansion Fe–Ni alloys. A two-shell atomic structure model is proposed to accurately locate the compositions of the alloy. In the presented model, the Cowley parameters of the alloy short-range ordered structure are considered. The selection of the first-nearest-neighbor cluster is determined, and the number and composition ratio of the second-nearest-neighbor atoms are evaluated by means of the spherical periodic oscillation model. The results show that the developed formula can provide a practical procedure for the composition design of low-expansion Fe–Ni alloys.

中文翻译：

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低膨胀铁镍合金的二最近邻结构模型与分析

该研究的主要目标是介绍一种用于分析低膨胀铁镍合金的二最近邻结构模型。提出了一种双壳原子结构模型来准确定位合金的成分。在所提出的模型中，考虑了合金短程有序结构的 Cowley 参数。确定了第一近邻簇的选择，并利用球形周期振荡模型评估了第二近邻原子的数量和组成比。结果表明，所开发的公式可以为低膨胀铁镍合金的成分设计提供一个实用的程序。