Experimental and modelling evidence for hydrogen trapping at a ß-Nb second phase particle and Nb-rich nanoclusters in neutron-irradiated low Sn ZIRLO
Experimental and modelling evidence for hydrogen trapping at a ß-Nb second phase particle and Nb-rich nanoclusters in neutron-irradiated low Sn ZIRLO
复制标题
中子辐照低 Sn ZIRLO 中的 β-Nb 第二相粒子和富 Nb 纳米团簇中氢捕获的实验和建模证据
DOI：
10.1016/j.jnucmat.2023.154755
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发表时间：
2023
影响因子：
3.1
通讯作者：
Jenkins B
中科院分区：
文献类型：
--
作者：
Jenkins B
用于核裂变反应堆燃料包壳的锆基合金在运行过程中容易发生氢脆，但目前我们对氢在材料使用过程中的行为缺乏必要的机械理解，无法正确解决这一问题。成像氢在材料微结构中的分布是建立或验证预测氢的行为和对材料性能影响的模型的关键，但在实验上是困难的。锆合金中氢的研究更加复杂，因为已知的最常见的用于制备用于透射电子显微镜和原子探针层析(APT)分析的样品的方法、电抛光和聚焦离子束(FIB)球磨都是诱导氢化物的形成。这就带来了不确定性，即被分析样品中的氢分布是否先验地代表了整个样品。最近的工作表明，这种影响可以通过在低温下进行最终的样品变薄阶段来缓解。本文用低温离子轰击技术制备了经中子辐照的低锡ZIRLO的APT样品，结果表明氢被捕获在β-Nb SPP中和中子辐照后形成的富Nb纳米团簇中。然后，我们使用密度泛函理论计算来解释这些实验观察。这些结果突显了在用于预测在使用期间的锆合金的氢吸收和在储存期间延迟氢化物破裂的模型中包含富Nb的特征的重要性。
Zirconium-based alloys used for fuel cladding in nuclear fission reactors are susceptible to hydrogen embrittlement during operation, but we currently lack the necessary mechanistic understanding of how hydrogen behaves in the materials during service to properly address this issue. Imaging the distribution of hydrogen within material microstructures is key to creating or validating models that predict the behaviour and influence of hydrogen on material properties, but is experimentally difficult. Studying hydrogen in zirconium-alloys is further complicated by the fact that the most common routes for preparing specimens for Transmission Electron Microscopy and Atom Probe Tomography (APT) analysis, electropolishing and focused ion beam (FIB) milling, are known to induce hydride formation. This introduces uncertainty as to whether the hydrogen distribution in the analysed specimen is actually representative of the entire sample a priori. Recent work has shown that this effect can be mitigated by performing the final specimen thinning stages at cryogenic temperatures. In this paper we use cryo-FIB to prepare APT specimens of neutron-irradiated low Sn ZIRLO, showing that hydrogen is trapped within a β-Nb SPP and at Nb-rich nanoclusters formed by exposure to neutron irradiation. We then use density functional theory calculations to explain these experimental observations. These results highlight the importance of including niobium-rich features in models used to predict hydrogen pick-up in zirconium alloys during service and delayed hydride cracking during storage.