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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“O_1-vacancy”和“O_2-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。
Vanadium (V) is an important candidate material for nuclear fusion reactor structural materials. Experiments show that the impurity oxygen (O) will have a great impact on the structure and mechanical properties of V. The first principles method based on density functional theory (DFT) is used to study the thermodynamic stability and diffusion properties of O in V and its interaction with defect vacancies. O easily occupy octahedral interstitial sites in V with a dissolution energy of -4.942 eV. O in the interstitial position of the best diffusion path for the octahedral space → → → tetrahedral interstitial spaces → octahedral interstitial spaces, the diffusion activation energy of 1.728 eV, based on which the diffusion coefficient at different temperatures in the text gives a detailed analysis . O has a strong attractive interaction with vacancies in V, and the trapping energies of one O atom and two O atoms when trapped by vacancy are -0.484 eV and -0.510 eV, respectively. When the number of O atoms is more than 3, the trap can become a positive value of 0.382 eV, so a single vacancy can combine up to two O atoms, which means that the clusters “O_1-vacancy” and “O_2-vacancy” V is easy to form. The results of these studies will be of certain reference value for the ultimate application of V-based alloys in nuclear fusion reactors.