First-principles investigation of hydrogen trapping and diffusion at grain boundaries in nickel
First-principles investigation of hydrogen trapping and diffusion at grain boundaries in nickel
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DOI：
10.1016/j.actamat.2015.07.031
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发表时间：
2015-10-01
期刊：
影响因子：
9.4
通讯作者：
Elsaesser, Christian
中科院分区：
文献类型：
--
作者：
Di Stefano, Davide;Mrovec, Matous;Elsaesser, Christian
在这项工作中，通过密度泛函理论模拟研究了氢与镍中大角度晶界的相互作用。考虑了两种不同类型的 GB：具有密堆积界面结构的 Sigma 3 (1 1 1)[(1) over bar 1 0] 和具有由开放结构单元组成的不太密集界面结构的 Sigma 5(2 1 0)[0 0 1]。我们的计算表明，这两个 GB 与原子氢具有明显不同的相互作用行为。密堆积的 Sigma 3 GB 既不捕获 H 也不增强其扩散，而是充当二维扩散势垒。相比之下，Sigma 5 GB 在开放结构单元内提供了许多 H 捕获位点，以及 H 沿着 GB 平面扩散的简单迁移路径，与块状 Ni 相比，可以将 H 扩散率提高约两个数量级。对所获得的结果进行了详细分析，并与可用的实验和其他理论数据进行了比较。 (C) 2015 Acta Materialia Inc. 由 Elsevier Ltd 出版。保留所有权利。
In this work, the interaction of hydrogen with high-angle GBs in nickel has been investigated by means of density functional theory simulations. Two distinct types of GBs have been considered: the Sigma 3 (1 1 1)[(1) over bar 1 0] with a close-packed interface structure and the Sigma 5(2 1 0)[0 0 1] with a less dense interface structure consisting of open structural units. Our calculations reveal that these two GBs have a markedly different interaction behavior with atomic hydrogen. The close-packed Sigma 3 GB neither traps H nor enhances its diffusion, but instead acts as a two-dimensional diffusion barrier. In contrast, the Sigma 5 GB provides numerous trapping sites for H within the open structural units as well as easy migration pathways for H diffusion along the GB plane that can enhance the H diffusivity by about two orders of magnitude compared to bulk Ni. The obtained results are analysed in detail and compared with available experimental and other theoretical data. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.