Alloying effects of Fe and Al on formation and decomposition temperatures of vanadium hydride, V2H
Alloying effects of Fe and Al on formation and decomposition temperatures of vanadium hydride, V2H
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DOI：
10.1016/j.ijhydene.2017.04.054
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发表时间：
2017-08
影响因子：
7.2
通讯作者：
R. Kawai;H. Yukawa;Asuka Suzuki;T. Nambu;Y. Murata
中科院分区：
文献类型：
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作者：
R. Kawai;H. Yukawa;Asuka Suzuki;T. Nambu;Y. Murata
在氢气气氛中，用一系列原位X射线衍射方法研究了铁、铝合金化对氢化钒β相形成和分解温度的影响。结果表明，铁的加入提高了β相的形成温度，而铝的加入使β相的形成温度急剧降低，根据第一原理计算，当氢原子插入合金元素的最近邻位时，铁、铬或镍的加入提高了氢的溶解能。这些结果被认为是对应于这些合金元素的加入增加了α-β相变的平台压力。合金化对氢插入T位总能量变化的影响大于O位。结果表明，这些合金元素的加入减小了T位模型和O位模型的能量差，提高了β相的形成温度。钒中的铝与氢之间表现出很强的排斥作用，使得氢不能在能量上占据铝的最近邻位。由于这种阻断作用，在钒中加入铝可显著降低β相的形成温度。
The alloying effects of iron and aluminum on the formation and decomposition temperatures of vanadium hydride, β phase, have been investigated by a series ofin-situX-ray diffraction measurements in hydrogen atmosphere. It is found that the addition of iron increases the formation temperature of β phase, while the addition of aluminum decreases the formation temperature drastically.According to the first principal calculations, the addition of iron, chromium or nickel increases the hydrogen dissolution energy when hydrogen atom is inserted to the nearest neighbor site of alloying element. These results is considered to correspond to the increase in the plateau pressure of α–β phase transition by the addition of these alloying elements. The alloying effect on the change in the total energy upon hydrogen insertion into T-site is larger than O-site. As a result, the energy difference between T-site model and O-site model becomes small by the addition of these alloying elements, which will lead to increase the formation temperature of β phase. Aluminum in vanadium shows strong repulsive interaction with hydrogen so that hydrogen cannot occupy the nearest neighbor sites of aluminum energetically. Owing to this blocking effects, the formation temperature of β phase may decreases drastically by the addition of aluminum into vanadium.