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采用第一性原理计算方法系统研究了合金化元素铌(Nb)对钨(W)中氦(He)溶解和扩散行为的影响.研究发现,Nb的存在显著降低了He在W中的溶解能,Nb可以作为W中He捕陷中心,在最稳定位置处Nb对He的捕陷能达到0.37 eV.通过电荷分析发现,这主要是因为Nb的存在引起了W中电荷密度的重新分布.而He在W中的扩散能垒将随着He—Nb间距离的缩小逐渐降低,这从动力学上表明He被Nb捕陷是可行的.因此,Nb的存在将有利于W中He的聚集成泡.
The influence of Nb on the dissolution and diffusion of He in tungsten (W) system was systematically investigated by the first-principles calculation method. It was found that the presence of Nb significantly reduced the solvational energy of He in W , Nb can be used as the center of He trap in W. The most stable position of Nb can reach 0.37 eV for He.It is mainly due to the existence of Nb that the distribution of charge density in W is redistributed by charge analysis The diffusion barrier of He in W gradually decreases with the decrease of the distance between He and Nb, which shows that it is feasible to trap He by Nb. Therefore, the existence of Nb will favor the aggregation of He in W bubble.