【摘要】 目的 揭示应变、置换型合金元素及间隙型合金元素对体心立方（BCC）铁中空位氢陷阱效应的影响机制，为提高钢材的抗氢脆性能提供理论支持。方法 基于密度泛函的第一性原理计算方法，系统研究了单轴应变及不同类型合金元素对BCC铁中空位的氢陷阱的结合能影响，计算分析了结构的电子密度分布和态密度。结果 单轴应变可以降低空位形成能，并对氢-空位结合能的影响呈现强烈的各向异性：垂直于应变轴的空位氢陷阱能力下降，而平行于应变轴的空位氢陷阱能力增强。此外，置换型合金元素（Mn、Si、Cr、Mo、Ti、W、Li、Al、Cu、Ni、Co、V）可通过调控局部电子结构和晶格畸变，在不同取向上分别削弱或增强氢的陷阱作用；间隙型合金元素（C、N）则通过引发显著的晶格畸变和电子结构重排，在空位周围形成2个稳定的氢捕获位点。结论 揭示了应变及合金元素对BCC铁中空位氢陷阱效应的微观机制，发现应变诱导的晶格畸变对氢陷阱能力具有方向性影响，而合金元素的体积参数和电子结构调控作用对氢-空位相互作用起决定性作用。这些结果为优化合金设计、提高钢材抗氢脆能力提供了重要的理论依据。更多还原

【Abstract】 The work aims to elucidate the mechanisms by which strain, substitutional alloying elements, and interstitial alloying elements affect hydrogen trapping at vacancies in body-centered cubic(BCC) iron, thereby providing theoretical guidance for enhancing hydrogen embrittlement resistance in steels. Based on first-principles calculations within the framework of density functional theory, the effects of uniaxial strain and various alloying elements on the binding energy of hydrogen-vacancy complexes in BCC iron were systematically investigated and the electronic charge density distributions and density of states were calculated and analyzed. The uniaxial strain reduced the vacancy formation energy and induced a pronounced anisotropy in hydrogen trapping behavior: hydrogen binding energy at vacancies aligned parallel to the strain axis was enhanced, while it was weakened in directions perpendicular to the axis. Substitutional alloying elements(Mn, Si, Cr, Mo, Ti, W, Li, Al, Cu, Ni, Co, and V) modulated the local electronic structure and lattice distortion, leading to orientation-dependent enhancement or suppression of hydrogen trapping. Interstitial elements(C and N) caused significant lattice distortion and electronic redistribution, generating two energetically favorable hydrogen trapping sites around the vacancy. These results uncover the microscopic mechanisms by which strain and alloying elements affect hydrogen-vacancy interactions in BCC iron. Strain-induced lattice distortion exhibits directional control over hydrogen trapping capacity, while the atomic size and electronic characteristics of alloying elements play a decisive role in modulating hydrogen-vacancy binding. These results provide essential theoretical insights for the design of advanced alloys with improved resistance to hydrogen embrittlement.更多还原