Department of Physics, Yantai University, Yantai, People's Republic of China.
J Phys Condens Matter. 2010 Nov 10;22(44):445504. doi: 10.1088/0953-8984/22/44/445504. Epub 2010 Oct 22.
We have investigated the structure, solution and diffusion behavior of carbon (C) in tungsten (W) based on first-principles calculations. The single C atom is energetically favorable sitting at the octahedral interstitial site (OIS) with a solution energy of 0.78 eV in W. Double C atoms tend to be paired up at the two neighboring OISs along the (210) direction with a distance of ∼ 3.57 Å and a binding energy of + 0.50 eV. This suggests that a positive attractive interaction between C atoms exists, which might lead to a local higher concentration of C in W and form carbide. Kinetically, the C and vacancy diffusion co-efficients as a function of temperature have been determined, and are 1.32 × 10(-19) m(2) s(-1) and 3.11 × 10(-23) m(2) s(-1) at a typical temperature of 600 K, respectively.
我们基于第一性原理计算研究了碳（C）在钨（W）中的结构、溶液和扩散行为。单个 C 原子在八面体间隙位（OIS）中能量有利，在 W 中的溶液能为 0.78 eV。两个相邻的 OIS 沿（210）方向的双 C 原子倾向于成对存在，距离约为 3.57 Å，结合能为+0.50 eV。这表明 C 原子之间存在正的吸引力相互作用，这可能导致 W 中 C 的局部浓度升高并形成碳化物。动力学方面，确定了 C 和空位扩散系数随温度的函数，在典型的 600 K 温度下，分别为 1.32×10(-19) m(2) s(-1)和 3.11×10(-23) m(2) s(-1)。
