北京航空航天大学学报 ›› 2017, Vol. 43 ›› Issue (5): 918-926.doi: 10.13700/j.bh.1001-5965.2016.0357

• 论文 • 上一篇    下一篇

氧在钒中基本热力学行为的第一性原理研究

桂漓江1, 刘悦林2   

  1. 1. 中国科学院 电工研究所, 北京 100190;
    2. 烟台大学 光电信息科学技术学院, 烟台 264005
  • 收稿日期:2016-04-29 出版日期:2017-05-20 发布日期:2017-05-27
  • 通讯作者: 刘悦林,E-mail:liuyl@ytu.edu.cn E-mail:liuyl@ytu.edu.cn
  • 作者简介:桂漓江, 男,博士。主要研究方向:凝聚态物理;刘悦林,男,博士,副教授。主要研究方向:凝聚态物理。
  • 基金资助:
    国家自然科学基金(11575153)

Basic thermodynamic property of oxygen in vanadium: A first-principles study

GUI Lijiang1, LIU Yuelin2   

  1. 1. Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China;
    2. School of Opto-electronic Information Science and Technology, Yantai University, Yantai 264005, China
  • Received:2016-04-29 Online:2017-05-20 Published:2017-05-27
  • Supported by:
    National Natural Science Foundation of China (11575153)

摘要: 钒(V)是核聚变反应堆结构材料的重要候选材料。实验表明杂质氧(O)会对V的结构和力学性能产生极大的影响。采用基于密度泛函理论的第一性原理方法研究了O在V中热力学稳定性、扩散特性以及与缺陷空位的相互作用。O在V中易于占据八面体间隙位,其溶解能为-4.942 eV。O在间隙位的最佳扩散路径为八面体间隙位→四面体间隙位→八面体间隙位,扩散激活能为1.728 eV,在此基础上对不同温度下的扩散系数在文中给出了详细分析。O在V中与空位存在很强的吸引相互作用,1个O原子和2个O原子被空位捕获时的捕获能分别为-0.484 eV和-0.510 eV。当O原子的数量超过3,其捕获能变为正值0.382 eV,因此单空位最多能够结合2个O原子,这意味着“O1-vacancy”和“O2-vacancy” 团簇在V中很容易形成。这些研究结果将对V基合金在核聚变反应堆中的最终应用具有一定的参考价值。

关键词: 钒, 杂质氧, 扩散特性, 缺陷空位, 第一性原理

Abstract: Vanadium (V) is identified as a promising candidate of the structural materials in fusion reactors. Experimental results have demonstrated that the impurity oxygen (O) has great influence on the structure and mechanical properties of V. Employing a first-principles method based on the density functional theory, we study the stability and diffusion property of impurity O as well as its interaction with defect vacancy in V. O atom is energetically favorable to occupy the octahedral insterstitial site with the solution energy of -4.942 eV. The intrinsic optimal diffusion route of O in the interstitial site is octahedral insterstitial site→tetrahedral insterstitial site→octahedral insterstitial site,and the diffusion activation energy is calculated to be 1.728 eV. The diffusion coefficients of O at the different temperature are systematically analyzed. We demonstrate that there is the strong attractive interaction between O and vacancy in V. The trapping energies of one and two O atoms are-0.484 eV and -0.510 eV, respectively. With the increase of the number of O atoms, the trapping energy of the third O becomes the positive value of 0.382 eV, meaning that vacancy cannot bind the additional O atom again. Thus, one vacancy can accommodate as many as two O atoms. It is revealed that the "O1-vacancy" and "O2-vacancy" clusters are easily formed in V. The current results can provide a very useful reference for V as a candidate structural material in a fusion reactor.

Key words: vanadium, impurity oxygen, diffusion property, defect vacancy, first-principles

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