Effects of Cr and W additions on the stability and migration of He in bcc Fe: A first-principles study

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• 作者：Ruihuan Li^a ; ^b ; Pengbo Zhang^a ; ^c ; Xiaojie Li^a ; Jianhua Ding^a ; Yuanyuan Wang^a ; Jijun Zhao^a ; ^{zhaojj@dlut.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Levente Vitos^b ; ^d
• 关键词：Iron ; Helium ; Chromium ; Tungsten ; Vacancy ; Diffusion ; Diffusivity
• 刊名：Computational Materials Science
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：123
• 期：Complete
• 页码：85-92
• 全文大小：1592 K

文摘

Density functional theory calculations have been performed to study the effects of alloying Cr and W on the stability and diffusivity of interstitial He impurity in body-centered cubic (bcc) Fe host lattice. The interaction between two close Cr/W atoms is repulsive. The relative stable position for an interstitial He remains the tetrahedral interstitial site in the presence Cr. Energetically, He prefers to locate far away from W inside Fe host lattice due to the strong repulsive interaction between He and W. On the other hand, the He migration barrier becomes lower in the presence of Cr (0.026 eV) and W (0.049 eV), as compared to 0.059 eV for pure Fe. Addition of Cr is benefit for He self-trapping, while W is against. The effective diffusivity of He decreases with increasing Cr and W concentrations. Moreover, the additions of Cr and W slightly hinder He being trapped by monovacancy.