First-principles investigation on diffusion and permeation behaviors of hydrogen isotopes in molybdenum
First-principles investigation on diffusion and permeation behaviors of hydrogen isotopes in molybdenum
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DOI：
10.1016/j.commatsci.2011.11.002
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发表时间：
2012-03
影响因子：
3.3
通讯作者：
Yuelin Liu;Shuo Jin;Lu Sun;C. Duan
中科院分区：
文献类型：
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作者：
Yuelin Liu;Shuo Jin;Lu Sun;C. Duan
我们通过第一性原理计算结合简化模型研究了氢 (H)、氘 (D) 和氚 (T) 在块体钼 (Mo) 中的扩散和渗透行为。经过量子校正后的H扩散能垒为0.12eV，与实验得到的0.11eV值非常吻合。根据Wert和Zener提出的扩散理论，分别估计了H、D和T的扩散系数。发现H扩散系数为D=1.27×10-7exp(-0.12eV/kT)m2s-1，这也与实验基本一致。渗透率 Φ 可以用 Φ=SD 来近似评估，其中 S 和 D 分别是溶解度和 H 扩散系数。我们发现H在块体Mo中的溶解度较低，这与早期实验中900K至1500K温度下的结果一致。 H同位素的渗透率经计算比实验值大一个数量级。这种差异应该源于当前计算中考虑了“无缺陷”Mo。最后检查H同位素的渗透通量。在1200K的温度下，计算出H、D和T的通量分别为1.27×10−6molm−2s−1、8.95×10−7molm−2s−1和7.30×10−7molm−2s−1。
We have investigated diffusion and permeation behaviors of hydrogen (H), deuterium (D), and tritium (T) in bulk molybdenum (Mo) by a first-principles calculations combined with simplified models. The H diffusion energy barrier with quantum correction is shown to be 0.12eV, in good agreement with the value of 0.11eV obtained from experiment. According to the diffusion theory presented by Wert and Zener, the diffusion coefficients of H, D and T are estimated, respectively. The H diffusion coefficient is found to be D=1.27×10-7exp(-0.12eV/kT)m2s-1, which is also basically consistent with the experiment. Permeability Φ can be approximately evaluated in terms of Φ=SD, where S and D are the solubility and the H diffusion coefficient, respectively. We found that H has the low solubility in bulk Mo, consistent with the results at the temperature from 900K to 1500K in the earlier experiment. The permeability of H isotopes are calculated to be one order of magnitude larger than those of the experimental values. Such discrepancy should stem from that the “defect-free” Mo in the present calculations is considered. The permeation flux of H isotopes are finally examined. At the temperature of 1200K, the fluxes of H, D, and T are calculated to be 1.27×10−6molm−2s−1, 8.95×10−7molm−2s−1, and 7.30×10−7molm−2s−1, respectively.