W中H行为的计算模拟研究

Modeling and Simulation of Hydrogen Behavior in Tungsten

采用基于密度泛函理论的第一原理计算方法和基于Newton力学的分子动力学方法,对H在W中的溶解、扩散、聚集、形核等行为及H对W性能影响进行系统研究,发现了H在W中占位和聚集的"最佳电子密度"规则,揭示了W中H泡形核的空位捕获机制;发现了H聚集诱发的各向异性应变可降低H在W中的溶解能,从而产生H溶解增强效应,藉此提出H泡生长的应变级联机制;提出通过惰性气体/合金化元素掺杂改变W中缺陷处的电子密度,有效阻止H2分子在缺陷处的形成和聚集,从而抑制W中H泡形成的方法。本文对这一系列的工作进行了综述。这些研究成果将为未来聚变堆用W-PFM的设计、制备和应用提供重要参考。

Based on national strategic needs for fusion energy, our group have investigated the behavior of H isotopes including dissolution, diffusion, accumulation and bubble formation in W using a firstprinciples method in combination with molecular dynamic method. It is found that the dissolution and nucleation of H in defects follow an ＂optimal charge density＂ rule, and a vacancy trapping mechanism for H bubble formation in W has been revealed. An anisotropic strain enhanced effect of H solubility due to H accumulation in W has been found, and a cascading effect of H bubble growth has been proposed. Noble gases/alloying elements doping in W has been proposed to suppress H bubble formation, because these dopants can change the distribution of charge density in defects and block the formation and nucleation of H2 molecule. These works are reviewed in this paper. Our calculations will provide a good reference for the design, preparation and application of W-PFM under a fusion environment.