In future fusion devices, the incident hydrogen plasma with high mobility can diffuse deep into tungsten bulk, which is directly relevant with hydrogen isotopes permeation and retention in tungsten. In this work, density functional theory (DFT) and object kinetic Monte Carlo (OKMC) simulations are adopted to investigate the hydrogen diffusion behavior in tungsten under anisotropic uniaxial strain from −2.5% to 2.5%. As presented by our DFT calculations, there are two types of hydrogen diffusion paths when applying strain, including one path perpendicular to the strain direction and another path largely along the strain direction. The migration energy barriers of these two paths have opposite variation tendencies in tensile or compressive condition. Our OKMC calculations based on DFT input show that, in tensile condition, the hydrogen diffusion is restrained despite the lower energy barrier of the corresponding diffusion path. In compressive condition, the hydrogen diffusion along the strain direction is enhanced, while that perpendicular to the strain direction is suppressed. The hydrogen diffusivity under anisotropic strain at the temperature range from 400 K to 1800 K is determined. It is demonstrated that tensile strain can suppress the diffusivity, while compressive strain can either suppress or facilitate the diffusivity depending on the temperature and the strain value. The anisotropic strain exhibits distinct effect on hydrogen diffusivity at lower temperature but its effect is minimal as the temperature increases.

在未来的聚变装置中，具有高迁移率的入射氢等离子体可以扩散到钨主体内部，这与氢同位素的渗透和在钨中的保留直接相关。在这项工作中，采用密度泛函理论（DFT）和对象动力学蒙特卡洛（OKMC）模拟来研究在-2.5％至2.5％各向异性单轴应变下钨在氢中的扩散行为。如我们的DFT计算所示，施加应变时有两种类型的氢扩散路径，包括一种垂直于应变方向的路径和另一种沿应变方向的路径。这两个路径的迁移能垒在拉伸或压缩条件下具有相反的变化趋势。我们基于DFT输入的OKMC计算表明，在拉伸条件下，尽管相应的扩散路径的能垒较低，但氢的扩散仍受到限制。在压缩状态下，沿应变方向的氢扩散得到增强，而与应变方向垂直的氢扩散得到抑制。测定在400 K至1800 K温度范围内的各向异性应变下的氢扩散率。已经证明，拉伸应变可以抑制扩散率，而压缩应变可以根据温度和应变值抑制或促进扩散率。各向异性应变在较低温度下对氢扩散率表现出明显的影响，但随着温度的升高其影响最小。沿应变方向的氢扩散得到增强，而与应变方向垂直的氢扩散得到抑制。测定在400 K至1800 K温度范围内的各向异性应变下的氢扩散率。已经证明，拉伸应变可以抑制扩散率，而压缩应变可以根据温度和应变值抑制或促进扩散率。各向异性应变在较低温度下对氢扩散率表现出明显的影响，但随着温度的升高其影响最小。沿应变方向的氢扩散得到增强，而与应变方向垂直的氢扩散得到抑制。测定在400 K至1800 K温度范围内的各向异性应变下的氢扩散率。已经证明，拉伸应变可以抑制扩散率，而压缩应变可以根据温度和应变值抑制或促进扩散率。各向异性应变在较低温度下对氢扩散率表现出明显的影响，但随着温度的升高其影响最小。而压缩应变可以根据温度和应变值抑制或促进扩散。各向异性应变在较低温度下对氢扩散率表现出明显的影响，但随着温度的升高其影响最小。而压应变可以根据温度和应变值抑制或促进扩散。各向异性应变在较低温度下对氢扩散率表现出明显的影响，但随着温度的升高其影响最小。