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论文类型：期刊论文
发表时间：2011-05-01
发表刊物：JOURNAL OF COMPUTATIONAL AND THEORETICAL NANOSCIENCE
收录刊物：Scopus、SCIE、EI
卷号：8
期号：5,SI
页面范围：858-861
ISSN号：1546-1955
关键字：Migration Barrier; First-Principle; Titanium Ditritide; Helium; Alloying
摘要：Tritium is an essential source used in nuclear industry; it is commonly stored in the form of metal tritide or ditritide. In these tritides, T will decay and form He-3. However, these formed 3He atoms do not immediately diffuse out of the lattice until some critical atomic ratio of He/Metal is reached, and the mechanism behind remains in debate. In order to shed lights on the physics controlling the diffusion of He atoms and formation of He bubbles, the alloying effects of 3d and 4d transition elements on the migration barrier of He in ideal titanium ditritide (TiT2) are studied by first-principles method. It is showed that the migration barrier, E-Mbarr, is a better criterion of alloying effect than the previously-used site-preferring energy, EM(8-4). The former criterion can explain perfectly the stay of inert He atom in metal tritides and give a more clear physical refraining mechanism on the diffusion of He atom and the nucleation of He bubbles. Using E-Mbarr, six beneficial alloying elements, namely Cr, Y, Nb, Ru, Pd and Ag, are further suggested out of the nineteen potential alloying elements evaluated.