Abstract High Entropy Alloys (HEA), where five or more elements are mixed together in near equiatomic ratios offer promising properties as hydrogen storage materials due to their ability to crystallize in simple cubic structures in the presence of large lattice strain originating from the different sizes of the atoms. In this work, the hydrogen absorption and desorption as well as the cycling properties of the TiZrNbHfTa HEA have been studied by in situ Synchrotron X-Ray diffraction, Pressure-Composition-Isotherm, Thermal Desorption Spectroscopy and Differential Scanning Calorimetry. The alloy crystallizes in a cubic bcc phase and undergoes a two-stage hydrogen absorption reaction to a fcc dihydride phase with an intermediate tetragonal monohydride, very similar to the V-H system. The hydrogen absorption/desorption in TiZrNbHfTa is completely reversible and the activation energy of desorption could be calculated. Furthermore, we have observed an interesting macrostructure following parallel planes after the formation of the dihydride phase, which is retained after desorption.

中文翻译：

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TiZrNbHfTa 高熵合金中的吸氢

摘要 高熵合金 (HEA)，其中五种或更多元素以接近等原子的比例混合在一起，提供了作为储氢材料的有前途的特性，因为它们能够在来自不同尺寸的大晶格应变的情况下以简单的立方结构结晶。原子。在这项工作中，通过原位同步加速器 X 射线衍射、压力成分等温线、热解吸光谱和差示扫描量热法研究了 TiZrNbHfTa HEA 的吸氢和解吸以及循环性能。该合金在立方体心立方相中结晶，并经过两阶段的吸氢反应形成具有中间四方一氢化物的 fcc 二氢化物相，与 VH 系统非常相似。TiZrNbHfTa 中的吸氢/解吸是完全可逆的，并且可以计算解吸的活化能。此外，我们在二氢化物相形成后观察到一个有趣的宏观结构，沿着平行平面，在解吸后保留。