北京航空航天大学学报

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镍晶界上金属和非金属元素的相互作用

方淑娟,石松鑫,祝令刚,周健   

  1. 北京航空航天大学材料科学与工程学院
  • 收稿日期:2017-05-09 修回日期:2017-06-29 发布日期:2017-09-18
  • 通讯作者: 祝令刚
  • 基金资助:
    国家自然科学基金

Interaction between metallic and nonmetallic elements on the grain boundary of nickel

  • Received:2017-05-09 Revised:2017-06-29 Published:2017-09-18

摘要: 采用基于密度泛函理论的第一性原理平面波赝势方法,研究了常用合金化金属元素与非金属元素在晶界的偏析及其相互作用。选取两种类型的晶界结构进行研究:密排的Σ3(1 1 1)[-1 1 0]晶界和较疏松的Σ5(2 1 0)(0 0 1)晶界。能量计算表明,金属和非金属元素在Σ5晶界上均有明显的偏析行为,而在Σ3晶界上的偏析现象不明显。通过计算常用过渡族合金化元素与非金属杂质C、H、O、N、B在各自最稳定位置的相互作用能,发现Ru、Re、W、Ta对O有强烈的排斥作用,因此对晶界抗氧化有益处;Ta排斥H,有抗晶界氢脆的效果。通过对金属元素与非金属元素在晶界上相互作用的系统研究,为Ni合金的晶界工程提供有价值的参考。

关键词: 晶界偏析, 镍基高温合金, 氢脆, 点缺陷, 第一性原理计算

Abstract: First-principles calculations are used to study the segregation of metallic and nonmetallic elements as well as their interactions on the grain boundary (GB) of nickel. Two typical GBs are constructed: close-packed Σ3(1 1 1)[-1 1 0] GB and quite open Σ5(2 1 0)(0 0 1) GB. According to the calculated energetic data, both the common transition alloying elements and nonmetallic elements C, H, O, N, B show strong segregation behavior on the Σ5 GB, while for the Σ3 GB, the segregation is not so significant. The interaction energies between the metallic elements with significant GB-segregation tendencies and nonmetallic elements when they occupy the most energy-favorable positions are investigated. It is found that Ru, Te, W and Ta exhibit strong repulsion to oxygen, indicating beneficial effects for the oxidation resistance behavior; Ta shows strong repulsive interaction to hydrogen, which should be helpful for the inhibition of the hydrogen-embrittlement. The present work should be useful for the grain boundary engineering of the Ni-based superalloy.

Key words: grain boundary segregation, Ni-based superalloy, hydrogen-embrittlement, point defect, first-principles calculation

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