Using a first-principles method in combination with thermodynamic models, we investigate the interaction between rhenium/osmium (Re/Os) and defects to explore the mechanism of radiation-induced Re/Os precipitation in tungsten (W). We demonstrate that radiation-induced defects play a key role in the solute precipitation in W, especially for self-interstitial atoms (SIAs). The presence of SIAs can significantly reduce the total nucleation free energy change of Re/Os, and thus facilitate the nucleation of Re/Os in W. Further, SIA is shown to be easily trapped by Re/Os once overcoming a low energy barrier, forming a W-Re/Os mixed dumbbell. Such W-Re/Os dumbbell forms a high stable Re/Os-Re/Os dumbbell structure with the substitutional Re/Os atoms, which can serve as a trapping centre for subsequent interstitial-Re/Os, leading to the growth of Re/Os-rich clusters. Consequently, an interstitial-mediated migration and aggregation mechanism for Re/Os precipitation in W has been proposed. Our results reveale that the alloying elements-defects interaction has significantly effect on their behaviors under irradiation, which should be considered in the design of W-based alloys for future fusion devices.

使用第一原理方法与热力学模型相结合，我们研究了// os（Re / Os）与缺陷之间的相互作用，以探索辐射诱发的钨（W）中Re / Os沉淀的机理。我们证明，辐射引起的缺陷在W中的溶质沉淀中起着关键作用，特别是对于自填隙原子（SIA）。SIA的存在可以显着减少Re / O的总成核自由能变化，从而促进W中Re / O的成核。此外，一旦克服了低能垒，SIA就会很容易被Re / O俘获，形成W-Re / Os混合哑铃。这样的W-Re / Os哑铃与Re / Os取代原子形成了高度稳定的Re / Os-Re / Os哑铃结构，可以用作随后的间质Re / Os的俘获中心，导致富含Re / Os的集群的增长。因此，提出了一种间隙介导的迁移和聚集机制，用于W中Re / Os的沉淀。我们的结果表明，合金元素-缺陷之间的相互作用对它们在辐照下的行为具有显着影响，这在未来熔合装置的W基合金设计中应予以考虑。