Trapping of hydrogen in metals
Trapping of hydrogen in metals
复制标题
金属中的氢捕获
DOI：
10.1007/3-540-08883-0_24
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发表时间：
1978
期刊：
影响因子：
--
通讯作者：
C. Wert
中科院分区：
文献类型：
--
作者：
C. Wert
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1
氢可以被捕获在固体的多种缺陷中。俘获的结合能与其他填隙原子（C、N 和 O）与缺陷的结合能处于同一数量级，只有十分之几 eV。然而，氢在金属中的高迁移率允许在比其他间隙原子低得多的温度下建立平衡；因此，捕获的效果更加明显。
2）
氢可以被捕获在宏观尺寸的空隙中。对于微观观察到的小空隙四面体，捕获的性质不太确定。对于尽可能小的空隙（晶格空位），捕获的细节甚至更不清楚。
3）
位错通过形成气氛来捕获氢。由于溶解氢原子的膨胀应变场在立方金属中可能具有近立方对称性，因此相互作用可能主要通过位错的膨胀应变场。因此，刃位错似乎具有很强的结合力（0.25 eV 量级），但螺旋位错可能几乎没有相互作用。
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应变场相互作用必须非常大，包括外部产生的应变以及边界和位错的内部应变。
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沿着位错核心的扩散增强似乎不确定，但移动位错可以有效地传输氢。
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杂质对氢的捕获非常明显，特别是 bcc 金属中的间隙原子 O、N 和 C。捕获能量通常为十分之几 eV。团簇的几何形状是不确定的，并且各种几何形状的团簇的相对结合能是未知的。
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1
Hydrogen can be trapped in many kinds of defects in solids. The binding energy of trapping is of the same order as that for other interstitials (C, N, and O) to defects— few tenths of an eV. However, the high mobility of hydrogen in metals permits equilibrium to be established at much lower temperatures than is true of the other interstitials ; thus, the effects of trapping are more pronounced.
2)
Hydrogen can be trapped in voids of macroscopic size. For small voids-tetrahedra observed microscopically—the nature of the trapping is less certain. For the smallest possible void—a lattice vacancy-the details of trapping are even less clear.
3)
Dislocations trap hydrogen by forming atmospheres. Since the dilatational strain field about a dissolved hydrogen atom may have nearly cubic symmetry in cubic metals, the interaction may mainly be through the dilatational strain field of a dislocation. Thus, edge dislocations appear to have strong binding (of order 0.25 eV) but screw dislocations may have little interaction.
4)
Strain field interactions must be very large, both externally produced strains and internal strains of boundaries and dislocations.
5)
Enhancement of diffusion along dislocations cores seems uncertain, but moving dislocations transport hydrogen effectively.
6)
Trapping of hydrogen by impurities is pronounced, especially by interstitials O, N, and C in bcc metals. Trapping energies are typically a few tenths of an eV. The geometry of the clusters is uncertain, and the relative binding energies of clusters of various geometries are not known.