Lattice strains due to hydrogen in metals
Lattice strains due to hydrogen in metals
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金属中氢引起的晶格应变
DOI：
10.1007/3540087052_42
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发表时间：
1978
影响因子：
3.7
通讯作者：
H. Peisl
中科院分区：
文献类型：
--
作者：
H. Peisl
氢溶解在许多金属中，并占据主体晶格中的间隙位置。在所有已知的金属-氢合金中，溶解的氢使主体金属的晶格膨胀。每一种氢间隙引起金属原子从其规则位置移位，由此产生的晶格扭曲(称为应变场或应力场)引起一系列物理性质的变化，引起了基础和应用研究活动。许多溶解大量氢的金属是现在或将来具有重要意义的技术材料，铁、钢、Nb、Ta、V和Pd及其合金就是这样的材料。Nb和V可能是聚变反应堆的建筑材料，而使用氢作为能源载体取决于储存容器和运输线路。由于每个金属原子中一个氢原子的溶解，典型的相对体积膨胀约为20%。如果在氢气环境中使用这种金属，这一事实可能会导致严重的建筑问题，因为建筑材料的尺寸发生了巨大变化。在金属-氢合金存在的广泛成分范围内观察到各种无序和有序相(见[参考文献])。3.1，第一章。2]))。由于晶格变形依赖于不同相中的氢浓度，不同相的形成与共格应力有关。由于这些相干应力，相变可能取决于样品的几何形状(第2)。如果共格应力超过临界屈服应力，它们会通过位错的形成而释放，位错本身会改变材料的性质。在原子尺度上，氢原子通过它们的畸变场相互作用(“弹性相互作用”)。根据Alefeld[3.2]，这种弹性相互作用是氢-Nb和氢-钯体系中c~-e‘相变的相关相互作用。氢原子和杂质之间的弹性相互作用也可能存在，并影响不同相的形核。氢与位错和内部(或外部)应力场的弹性相互作用，例如靠近材料中的裂纹，在最严重的力学性能变化--金属的氢脆中起着重要作用(见[参考文献]。3.1，第一章。9]))。
Hydrogen dissolves in many metals and occupies interstitial sites in the host lattice. In all known metal-hydrogen alloys the dissolved hydrogen expands the crystal lattice of the host metal. Each hydrogen interstitial causes displacements of the metal atoms from their regular sites, and the resulting crystal lattice distortions (described as strain or stress fields) give rise to a series of physical property changes which have attracted both fundamental and applied research activities.Many of the metals which dissolve large quantities of hydrogen are technological materials of present or future importance, lron, steel, Nb, Ta, V, and Pd and its alloys are such materials. Nb and V are possible candidates as construction materials in fusion reactors, and using hydrogen as an energy carrier depends on storage containers and transport lines. Typical relative volume expansions due to the solution of one hydrogen atom per metal atom are of the order of 20%. This fact could cause severe construction problems if such metals are used in a hydrogen environment owing to the drastic change in the dimensions of the construction materials. A variety of disordered and ordered phases are observed over the wide range of composition in which metal-hydrogen alloys exist (see [Ref. 3.1, Chap. 2]). As the lattice distortions depend on the hydrogen concentrations in the various phases, the formation of a different phase is connected with coherency stresses. The phase transitions may depend on the sample geometry due to these coherency stresses (Chap. 2). If the coherency stresses exceed the critical yield stress they are released by the formation of dislocations which themselves change the properties of the material. On an atomistic scale the hydrogen atoms interact via their distortion fields (" elastic interaction"). According to Alefeld [3.2], this elastic interaction is the relevant interaction for the c~-e'phase transition in the hydrogen-niobium and hydrogen-palladium system. An elastic interaction between the hydrogen atoms and impurities may also exist and influence the nucelation of a different phase. The elastic interaction of hydrogen with dislocations and internal (or external) stress fields, eg, close to a crack in the material, plays an important role in the most serious mechanical property change, the hydrogen embrittlement of metals (see [Ref. 3.1, Chap. 9]).