We report first-principles results of the point defect properties in a V-Ta-Cr-W high-entropy alloy (HEA) with the body-centered cubic (bcc) structure. Different from the widely-investigated face-centered cubic (fcc) HEAs, the local lattice distortion is more pronounced in bcc ones, which has a strong influence on the defect properties and defect evolution under irradiation. Due to the large size of Ta, the exchange between vacancies and Ta exhibits lower energy barriers. On the other hand, interstitial dumbbells containing V and Cr possess lower formation energies. These defect energetics predicts an enrichment of V and Cr and a depletion of Ta and W in the vicinity of defect sinks. Besides, we find that interstitial dumbbells favor the [110] orientation in the HEA, instead of [111] direction in most nonmagnetic bcc metals, which helps to slow down interstitial diffusion significantly. Consequently, the distribution of migration energies for vacancies and interstitials exhibit much larger overlap regions in the bcc HEA compared to fcc HEAs, leading to the good irradiation resistance by enhancing defect recombination. Our results suggest that HEAs with the bcc structure may bear excellent irradiation tolerance due to the particular defect properties.

我们报告具有体心立方（bcc）结构的V-Ta-Cr-W高熵合金（HEA）中点缺陷性质的第一性原理结果。与广泛研究的面心立方（fcc）HEA不同，bcc晶格中的局部晶格畸变更为明显，这对辐照下的缺陷性质和缺陷演化有很大影响。由于Ta的尺寸大，空位和Ta之间的交换显示出较低的能垒。另一方面，含有V和Cr的填隙哑铃具有较低的形成能。这些缺陷能量学预测缺陷缺陷附近V和Cr的富集以及Ta和W的耗尽。此外，我们发现，间隙哑铃有利于HEA的[110]方向，而不是大多数非磁性bcc金属的[111]方向，这有助于显着减慢间隙扩散。因此，与fcc HEA相比，bcc HEA中空位和间隙的迁移能分布表现出大得多的重叠区域，从而通过增强缺陷重组而获得了良好的耐辐照性。我们的结果表明，与由于特殊的缺陷特性，密件抄送结构可能具有出色的辐射耐受性。