ABSTRACT After the core meltdown in the Fukushima Daiichi (1F) nuclear power plant, various compounds in metal boride systems could potentially form as a result of the reactions between B4C (control material) and Fe, Zr alloys (control-blade sheaths, zircaloy claddings, channel box, etc.). Some previous studies have focused on the properties of intermetallic compounds of the Zr-B and Fe-B systems, such as ZrB2, FeB, and Fe2B. However, during the solidification of fuel debris, composites of these intermetallics rather than large chunks of single-phase intermetallics will form. This situation makes the understanding of the composition dependence of the mechanical and thermal properties of these metal borides a major task before debris retrieval takes place. In this study, we first investigated the temperature-dependent thermal conductivity of Fe-B and Zr-B eutectics from room temperature up to 900°C. We were then able to evaluate the composition-dependent indentation hardness of these metal borides at room temperature. Based on our experimental data, we concluded that the hardness and thermal conductivity of the Fe-B, Zr-B composites can be well estimated using the properties of the composites’ corresponding components, with Rule of Mixtures and Effective Medium Theory (EMT) calculations, respectively.

中文翻译：

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Zr-B 和 Fe-B 合金的机械和热性能

摘要 在福岛第一核电站 (1F) 堆芯熔化后，由于 B4C（控制材料）与 Fe、Zr 合金（控制叶片护套、锆合金包壳）之间的反应，可能会在金属硼化物系统中形成各种化合物。 、通道盒等）。以前的一些研究集中在 Zr-B 和 Fe-B 系统的金属间化合物的性质上，例如 ZrB2、FeB 和 Fe2B。然而，在燃料碎片凝固过程中，将形成这些金属间化合物的复合物，而不是大块的单相金属间化合物。这种情况使得在碎片回收发生之前了解这些金属硼化物的机械和热性能的成分依赖性成为一项主要任务。在这项研究中，我们首先研究了 Fe-B 和 Zr-B 共晶物从室温到 900°C 的温度依赖性热导率。然后，我们能够评估这些金属硼化物在室温下与成分相关的压痕硬度。根据我们的实验数据，我们得出结论，Fe-B、Zr-B 复合材料的硬度和热导率可以使用复合材料相应组分的特性、混合物规则和有效介质理论 (EMT) 计算得到很好的估计， 分别。