Inert gas bubbles in bcc Fe
Inert gas bubbles in bcc Fe
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DOI：
10.1016/j.jnucmat.2015.11.057
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发表时间：
2016-03-01
影响因子：
3.1
通讯作者：
Kenny, S. D.
中科院分区：
文献类型：
--
作者：
Gai, Xiao;Smith, Roger;Kenny, S. D.
体心立方铁中惰性气体气泡的性质研究使用静态能量最小化，分子动力学和势垒搜索方法与经验电位相结合。静态能量最小化技术表明，对于小的Ar和Ar+气泡，在0 K下优选的气体与空位比对于Ar约为1：1，对于Ar+在0.5：1和0.9：1之间变化。与在晶格中高度移动的间隙He原子和小的He间隙团簇相反，Ar和Ar原子更喜欢占据替代位点，并且晶格中存在的任何杂质很快取代Fe原子并成为替代的。如果存在预先存在的气泡，则存在围绕气泡的捕获半径，该捕获半径延伸到第6个相邻位置。碰撞级联也可以通过捕获空位来扩大现有的气泡。Ar和H2O可以通过空位驱动机制扩散通过晶格，但分别具有1.8和2.0 eV的相对较高的能垒。这表明Ar和Ar+气泡比He气泡更难形成，并且在核反应中产生的这些气体更可能在没有增加的温度或辐射驱动机制的帮助下分散在替代位点。(C)2015作者由Elsevier B.V.发布，这是CC BY许可下的开放获取文章。
The properties of inert gas bubbles in bcc Fe is examined using a combination of static energy minimisation, molecular dynamics and barrier searching methods with empirical potentials. Static energy minimisation techniques indicate that for small Ar and Xe bubbles, the preferred gas to vacancy ratio at 0 K is about 1:1 for Ar and varies between 0.5:1 and 0.9:1 for Xe. In contrast to interstitial He atoms and small He interstitial clusters, which are highly mobile in the lattice, Ar and Xe atoms prefer to occupy substitutional sites and any interstitials present in the lattice soon displace Fe atoms and become substitutional. If a pre-existing bubble is present then there is a capture radius around a bubble which extends up to the 6th neighbour position. Collision cascades can also enlarge an existing bubble by the capture of vacancies. Ar and Xe can diffuse through the lattice through vacancy driven mechanisms but with relatively high energy barriers of 1.8 and 2.0 eV respectively. This indicates that Ar and Xe bubbles are much harder to form than bubbles of He and that such gases produced in a nuclear reaction would more likely be dispersed at substitutional sites without the help of increased temperature or radiation-driven mechanisms. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.