Interplay of solute-mixed self-interstitial atoms and substitutional solutes with interstitial and substitutional helium atoms in tungsten-transition metal alloys
Interplay of solute-mixed self-interstitial atoms and substitutional solutes with interstitial and substitutional helium atoms in tungsten-transition metal alloys
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DOI：
10.1088/1741-4326/aaf297
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发表时间：
2018-12
期刊：
影响因子：
3.3
通讯作者：
Y. You;Jingjing Sun;Xuebang Wu;Yichun Xu;Tao Zhang;T. Hao;Qianfeng Fang;Changsong Liu
中科院分区：
文献类型：
--
作者：
Y. You;Jingjing Sun;Xuebang Wu;Yichun Xu;Tao Zhang;T. Hao;Qianfeng Fang;Changsong Liu
在聚变堆环境中，中子和氦等离子体的辐照会在钨中产生大量的自填隙原子和空位，这些自填隙原子和空位不可避免地与合金溶质相互作用，形成混合的自填隙原子和替位溶质。溶质与He原子的相互作用影响两者的行为，最终导致溶质沉淀和He气泡的形成，但其微观机制仍然是个谜。在这项工作中，我们进行了系统的从头计算研究溶质和He原子的相互影响，他们的行为。据发现，大多数考虑的溶质紧密结合最稳定的哑铃形成混合或哑铃。溶质混合哑铃状结构可以作为氦原子的俘获中心。混合哑铃与间隙He原子的结合非常紧密，所有的结合能都大于1.0 eV。与He存在时形成W Frenkel对所需的能量相比，形成大多数溶质混合Frenkel对所需的能量降低，而钛、锆、铌、铪和钽混合Frenkel对是例外。类似地，替代溶质也可以捕获间隙和替代He原子，并且溶质与间隙He的结合更强，其次是溶质，而替代溶质与替代He原子的相互作用则相反。分析了控制混合哑铃型和替代型溶质与间隙型和替代型He原子相互作用的根本原因。
In a fusion reactor environment, the irradiation of neutrons and helium (He) plasma produces a great number of self-interstitial atoms and vacancies in tungsten (W), which inevitably interact with alloying solutes to form mixed self-interstitial atoms and substitutional solutes. The interactions of solutes with He atoms affect the behaviors of both, and ultimately cause the formation of solute precipitates and He bubbles; however, the micro-mechanisms of this are still mysterious. In this work, we perform systematic ab initio calculations to study the mutual influence of solutes and He atoms on their behaviors. It is found that most of the considered solutes bind tightly with the most stable dumbbells forming mixed or dumbbells. Solute-mixed dumbbells can act as trapping centers for He atoms. Mixed dumbbells bind very tightly with interstitial He atoms and all the binding energies are larger than 1.0 eV. Compared with the energy for the formation of a W Frenkel pair with the presence of He, the energies needed for the formation of most solute-mixed Frenkel pairs are decreased while titanium, zirconium, niobium, hafnium, and tantalum-mixed Frenkel pairs are exceptions. Similarly, substitutional solutes can also trap interstitial and substitutional He atoms, and solutes bind stronger with interstitial He followed by and solutes while it is the opposite for interactions of substitutional solutes with substitutional He atoms. The underlying reasons controlling the interactions of mixed dumbbells and substitutional solutes with interstitial and substitutional He atoms are analyzed.