Hydrogen and its isotopes, absorbed in metals, induce local stress on the atomic structure, which generates a global expansion in proportion to the concentration of hydrogen. The dipole force tensor and its interaction with the stress fields give rise to an effective attractive nonlocal potential between hydrogen atoms—the elastic hydrogen-hydrogen interaction—which is a key quantity governing the phase transitions of hydrogen in metals. While the dipole tensor and the elastic interaction have been researched in crystalline materials, they remain experimentally unexplored in metallic glasses and it is unclear how these quantities are affected by the lack of point group symmetries. Here, we investigate both experimentally and theoretically the volume changes, the components of the force dipole tensor, and ultimately the elastic hydrogen-hydrogen interaction in the metallic glass ${\mathrm{V}}_{80}{\mathrm{Zr}}_{20}$. In situ neutron reflectometry was used to determine the deuterium-induced volume changes as a function of deuterium concentration. The one-dimensional volume expansion is found to change by more than 14% without any structural degradation, up to concentrations of one deuterium atom per metal atom. From the expansion, we determine that the out-of-plane component of the elastic dipole tensor is remarkably similar to a composition weighted sum of the ones found in crystalline vanadium and zirconium. Via ab initio calculations of both free and biaxially constrained expanded metallic structures, we determine that the trace of the dipole tensor varies with hydrogen concentration and is essentially invariant of global elastic boundary conditions. As a consequence, the elastic hydrogen-hydrogen interaction energy is found to be concentration-dependent as well, illustrating that the disordered nature of a metallic glass does not impede the mediation of the elastic attraction, but rather allows it to vary with hydrogen content.

中文翻译：

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金属玻璃中氢引起的体积变化、偶极子张量和弹性氢-氢相互作用

吸收在金属中的氢及其同位素会在原子结构上引起局部应力，从而产生与氢浓度成比例的全局膨胀。偶极子力张量及其与应力场的相互作用在氢原子之间产生了有效的吸引非局域势——弹性氢-氢相互作用——这是控制金属中氢相变的关键量。虽然已经在晶体材料中研究了偶极子张量和弹性相互作用，但它们在金属玻璃中仍未进行实验探索，并且尚不清楚这些量如何因缺乏点群对称性而受到影响。在这里，我们从实验和理论上研究了体积变化，力偶极子张量的分量，${\mathrm{五}}_{80}{锆}_{20}$. 原位中子反射仪用于确定氘引起的体积变化作为氘浓度的函数。发现一维体积膨胀变化超过 14% 而没有任何结构退化，每个金属原子的浓度高达一个氘原子。通过展开，我们确定弹性偶极子张量的面外分量与结晶钒和锆中发现的分量加权和非常相似。从头算起通过对自由和双轴约束膨胀金属结构的计算，我们确定偶极子张量的轨迹随氢浓度而变化，并且基本上不受全局弹性边界条件的影响。因此，发现弹性氢-氢相互作用能也与浓度相关，说明金属玻璃的无序性质不会阻碍弹性吸引力的中介，而是允许它随氢含量而变化。