Abstract Compounds based on Fe2VAl are good candidates for low grade heat harvesting owing to the thermoelectric effect. However, it is claimed that their thermoelectric properties are badly influenced by antisite defects, especially at higher temperatures. The present study investigates order-disorder transitions in Fe2VAl ternary Heusler compounds. An inherent problem of these compounds is the close atomic numbers of Fe and V, leading to similar x-ray atomic scattering factors. Hence, the D03 and L21 structures, corresponding to Fe-V antisite defects, are hardly distinguishable by X-ray diffraction. In this work, anomalous scattering and neutron diffraction were successfully combined with differential scanning calorimetry to highlight the order-disorder transitions in Fe2VAl-based compounds. A model has been developed to quantify the ordering parameters. From these results, specific heat-treatments were defined to promote the formation of the L21 ordered phase.

中文翻译：

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通过 X 射线反常衍射表征非化学计量 Fe 2 VAl 基 Heusler 化合物中的反位缺陷和有序性

摘要 由于热电效应，基于 Fe2VAl 的化合物是低品位热量收集的良好候选材料。然而，据称它们的热电性能受到反位缺陷的严重影响，尤其是在较高温度下。本研究调查了 Fe2VAl 三元 Heusler 化合物中的有序-无序转变。这些化合物的一个固有问题是 Fe 和 V 的原子序数接近，导致相似的 X 射线原子散射因子。因此，对应于 Fe-V 反位缺陷的 D03 和 L21 结构很难通过 X 射线衍射区分。在这项工作中，反常散射和中子衍射成功地与差示扫描量热法相结合，以突出 Fe2VAl 基化合物中的有序-无序转变。已经开发了一个模型来量化排序参数。根据这些结果，定义了特定的热处理以促进 L21 有序相的形成。