Study of hydrogen diffusion in Nb-Ta alloys by Gorsky effect measurement
Study of hydrogen diffusion in Nb-Ta alloys by Gorsky effect measurement
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DOI：
10.1016/j.msea.2006.03.128
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发表时间：
2006-12
期刊：
影响因子：
6.4
通讯作者：
T. Mugishima;M. Yamada;O. Yoshinari
中科院分区：
文献类型：
--
作者：
T. Mugishima;M. Yamada;O. Yoshinari
在160 ~ 340K温度范围内，通过测量戈尔斯基效应，研究了氢在NbxTa1−x合金（x=0、0.1、0.25、0.5、0.75、0.9和1.0）中的扩散。当x=0、0.9和1.0时，合金的氢扩散系数D在低温下偏离Arrhenius型，而其他合金则不偏离Arrhenius型。在富Nb端和富ta端，D随合金的加入而减小，在x处达到最小值。D的浓度依赖性在富铌端强于富ta端。由第一性原理计算得到的氢势表明，在铌矩阵中，Ta原子是氢的俘获中心，而在Ta矩阵中，Nb原子是反俘获中心。结果表明，富铌和富ta合金D值下降的主要原因不同：前者是氢捕获，后者是隧穿跳变的干扰。
Hydrogen diffusion in NbxTa1−xalloys (x=0, 0.1, 0.25, 0.5, 0.75, 0.9 and 1.0) was investigated over a temperature range between 160 and 340K by measurements of the Gorsky effect. The temperature dependence of the hydrogen diffusivity, D, of specimens with x=0, 0.9 and 1.0 showed a deviation from the Arrhenius type behavior at low temperatures, while the other alloys did not show such a deviation. The value of D decreases with alloying at both the Nb- and Ta-rich ends and exhibits a minimum at x≃0.50. The concentration dependence of D is stronger at the Nb-rich end than that at the Ta-rich end. The hydrogen potential obtained by a first-principles calculation shows that a Ta atom acts as a trapping center for hydrogen in the Nb matrix and a Nb atom acts as an anti-trapping center in the Ta matrix. It is concluded that the main reason for the decrease in D is different for the Nb-rich and Ta-rich alloys: the hydrogen trapping for the former and a disturbance of tunneling jump for the latter.