Abstract Multi-principal-element alloys, including high-entropy alloys, experience segregation or partially-ordering as they are cooled to lower temperatures. For Ti0.25CrFeNiAlx, experiments suggest a partially-ordered B2 phase, whereas CALculation of PHAse Diagrams (CALPHAD) predicts a region of L21+B2 coexistence. We employ first-principles density-functional theory (DFT) based electronic-structure approach to assess stability of phases of alloys with arbitrary compositions and Bravais lattices (A1/A2/A3). In addition, DFT-based linear-response theory has been utilized to predict Warren-Cowley short-range order (SRO) in these alloys, which reveals potentially competing long-range ordered phases. The resulting SRO is uniquely analyzed using concentration-waves analysis for occupation probabilities in partially-ordered states, which is then be assessed for phase stability by direct DFT calculations. Our results are in good agreement with experiments and CALPHAD in Al-poor regions (x ≤ 0.75) and with CALPHAD in Al-rich region (0.75 ≤ x ≤ 1), and they suggest more careful experiments in Al-rich region are needed. Our DFT-based electronic-structure and SRO predictions supported by concentration-wave analysis are shown to be a powerful method for fast assessment of competing phases and their stability in multi-principal-element alloys.

中文翻译：

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任意高熵合金初阶的第一性原理预测：以 Ti0.25CrFeNiAl 为例

摘要 多主元素合金，包括高熵合金，在冷却到较低温度时会发生偏析或部分有序。对于 Ti0.25CrFeNiAlx，实验表明存在部分有序的 B2 相，而 PHAse 图的计算 (CALPHAD) 预测 L21+B2 共存区域。我们采用基于第一性原理密度泛函理论 (DFT) 的电子结构方法来评估具有任意成分和布拉维晶格 (A1/A2/A3) 的合金相的稳定性。此外，基于 DFT 的线性响应理论已被用于预测这些合金中的 Warren-Cowley 短程有序 (SRO)，这揭示了潜在的竞争性长程有序相。使用集中波分析对偏序状态下的占领概率进行唯一分析，得出的 SRO，然后通过直接 DFT 计算评估相位稳定性。我们的结果与贫铝区域 (x ≤ 0.75) 中的实验和 CALPHAD 以及富铝区域 (0.75 ≤ x ≤ 1) 中的 CALPHAD 非常一致，它们表明需要在富铝区域进行更仔细的实验​​。我们由浓度波分析支持的基于 DFT 的电子结构和 SRO 预测被证明是一种强大的方法，可以快速评估多主要元素合金中的竞争相及其稳定性。