Alloy design of cyclic hydro and dehydrogenation tolerant hydrogen storage materials

本研究的目的是了解冶金因素对吸氢性能的影响，为具有先进循环性能的储氢材料的合适合金设计提供参考。显微组织和成分对二元TiMn_2基合金吸氢性能的影响：在Ti-59.4 ~ -66.8 at范围内研究了二元TiMn_2基合金吸氢性能随成分的变化规律。%锰。随着Mn含量的增加，TiMn_2相分数体积增大。TiMn_2相的Mn含量基本稳定在Ti-56.4 ~ -59.4 at之间。在Ti-59.4 ~ -66.8之间，随Mn含量的增加而增大。%锰。ti - 59.4。% Mn含TiMn_2相60 at。% Mn表现出优异的吸氢能力，在重复吸氢和解吸过程中，其吸氢能力的退化最小。结果表明，提高TiMn_2相的体积分数，尽量降低Mn含量，可以提高二元TiMn_2基合金的吸氢能力和循环性能。TiMn_2基合金：循环氢化TiMn_2 （ti - 60at）吸氢能力的退化。采用压力-成分-等温线（PCT）测量、x射线衍射和显微组织观察等方法对Laves结构进行了研究。循环氢化反应的特征变化如下。吸氢能力显著降低，晶格常数增大，TiMn_2中留氢量增加，在真空中673 K脱氢后几乎为零。在TiMn_2中加氢生成了具有Mere图案的纳米区域，衍射图中出现了与氢化钛δ-TiH对应的Debye环。基于这些观察结果，得出循环加氢后吸氢能力的下降是由于引入了残留氢、非均相应变和/或纳米区。少

The objective of this study is to understand the effect of metallurgical factors on hydrogen absorbing properties and to indicate the appropriate alloys design of hydrogen storage materials with advanced cyclic properties. The results obtained are summarized as followsEffects of microstructure and composition on hydrogen absorbing properties in binary TiMn_2 based alloy: The hydrogen absorbing properties of binary TiMn_2 based alloys have been investigated as function of composition in the range between Ti-59.4 and -66.8 at.% Mn. The volume of fraction of TiMn_2 phase increases with increasing Mn content. The Mn content of TiMn_2 phase is almost constant atcompositions between Ti-56.4 and -59.4 at.% Mn, while is increases with increasing Mn content at compositions between Ti-59.4 nod -66.8 at.% Mn. Ti-59.4 at.% Mn containing TiMn_2 phase with 60 at.% Mn exhibits the superior hydrogen absorbing capacity and she least degradation of capacity during repeated hydrogen absorption and desorp … More tion. It is concluded that both hydrogen absorbing capacity and cyclic property in binary TiMn_2 based alloy are improved by increasing the volume fraction of TiMn_2 phase with keeping Mn content as low as possible.TiMn_2 based alloys: Degradation of the hydrogen absorbing capacity in cyclically hydrogenated TiMn_2 (Ti-60 at.% Mn) with Laves structure was studied by measurement of pressure-composition-isotherm (PCT) curves, X-ray diffraction and microstructure observation. Characteristic changes with cyclic hydrogenation are observed as follows. The hydrogen absorbing capacity remarkably decreases, the lattice constant increases, the amount of hydrogen retained in TiMn_2 increases and it approaches almost zero by dehydrogenation as 673 K in vacuum. Nano-sized regions with Mere patterns are produced in TiMn_2 with hydrogenation and Debye rings corresponding to titanium hydride δ-TiH appear in the diffraction pattern. Based on these observations it is concluded that the degradation of hydrogen absorbing capacity after cyclic hydrogenation is attributable to the introduction of retained hydrogen, heterogeneous strain and/or nano-regions. Less