发表机构
KU Leuven; Department of Materials Engineering, Faculty of Engineering, KU Leuven; Department of Computer Science, Faculty of Engineering Science, KU Leuven（荷语鲁汶大学; 荷语鲁汶大学工程学院材料工程系; 荷语鲁汶大学工程科学学院计算机科学系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究提出定量相场模型，揭示晶界捕集与扩散对氢输运的耦合影响，证明晶界扩散可显著改变TDS峰，使Kissinger分析失效，并强调晶粒尺寸、温度等因素对有效扩散系数的重要作用。
AI 中文摘要
晶界通过充当捕集位点和相互连通的扩散路径，影响多晶金属中的氢输运。传统上对热脱附谱（TDS）和渗透实验的解释往往将捕集位视为孤立缺陷，忽略了晶界的连通性，可能导致对实验数据的误判。在此，我们开发了一个用于氢扩散、晶界捕集和晶界辅助输运的定量相场模型。该公式独立于数值界面厚度，保留了物理晶界体积，并考虑了平行和垂直于晶界的各向异性扩散。基准模拟验证了界面放大下的定量行为。模型表明，晶界扩散可显著移动TDS峰，使得当晶界输运显著时，Kissinger型分析变得不可靠。有效扩散系数也被证明强烈依赖于晶粒尺寸、捕集自由能、温度和晶界迁移率。这些结果凸显了捕集热力学、体扩散和晶界输运的耦合作用。
英文摘要
Grain boundaries influence hydrogen transport in polycrystalline metals by acting as both trapping sites and interconnected diffusion pathways. Conventional interpretations of thermal desorption spectroscopy (TDS) and permeation experiments often treat traps as isolated defects, neglecting grain boundary connectivity and potentially misinterpreting experimental data. Here, we develop a quantitative phase-field model for hydrogen diffusion, grain boundary trapping, and grain boundary-assisted transport. The formulation preserves the physical grain boundary volume independently of the numerical interface thickness and accounts for anisotropic diffusion parallel and perpendicular to grain boundaries. Benchmark simulations verify quantitative behavior under interface upscaling. The model shows that grain boundary diffusion can significantly shift TDS peaks, making Kissinger-type analyses unreliable when grain boundary transport is significant. Effective diffusion coefficients are also shown to depend strongly on grain size, trapping free energy, temperature, and grain boundary mobility. These results highlight the coupled role of trapping thermodynamics, bulk diffusion, and grain-boundary transport.
