Development of EAM Potential for Fe with Pseudo-Hydrogen Effects and Molecular Dynamics Simulation of Hydrogen Embrittlement
Development of EAM Potential for Fe with Pseudo-Hydrogen Effects and Molecular Dynamics Simulation of Hydrogen Embrittlement
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DOI：
10.2472/jsms.61.175
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
Shoichi Seki;R. Matsumoto;Y. Inoue;S. Taketomi;N. Miyazaki
中科院分区：
文献类型：
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作者：
Shoichi Seki;R. Matsumoto;Y. Inoue;S. Taketomi;N. Miyazaki
大量的研究报道了溶质氢原子和晶格缺陷有很强的相互作用，并且氢原子显著地改变了晶格缺陷的稳定性和/或迁移率。虽然分子动力学（MD）模拟可以处理各种晶格缺陷的复杂相互作用，但时间尺度不足以处理氢的扩散，从而影响晶格缺陷的产生以及氢原子与晶格缺陷的协同运动。在这里，我们开发了铁的原子间势，并对晶格缺陷能进行了伪氢效应，并进行了拉伸加载的MD模拟。首先，我们利用第一性原理计算估计了铁的晶格缺陷能和晶格缺陷的氢阱能，并在实际的气态氢环境下评估了晶格缺陷能。其次，我们修正了现有的嵌入原子法Fe势，以表示氢效应修正的晶格缺陷能。最后，我们通过估计未用于势拟合的晶界能的再现性，证实了我们的势适用于各种现象。我们对纳米试样的拉伸加载模拟表明，氢降低了断裂伸长率。
Numerous studies have reported that solute hydrogen atoms and lattice defects have strong interactions, and that hydrogen atoms significantly change the stability and/or mobility of lattice defects. Although molecular dynamics (MD) simulations can treat complicated interactions of various lattice defects, the time scale is insufficient to treat hydrogen diffusion so as to influence the lattice-defect generation and cooperative motion of hydrogen atoms and lattice defects. Here we developed an interatomic potential for Fe with pseudo-hydrogen effects on lattice-defect energies and performed MD simulations of tensile loading. First, we estimated the lattice-defect energies of Fe and hydrogen-trap energies of lattice defects by using first-principle calculations and evaluated the lattice-defect energies under a practical gaseous hydrogen environment. Second, we refitted the existing embedded-atom-method potential for Fe to represent the lattice-defect energies amended by hydrogen effects. Finally, we confirmed that our potential is applicable for various phenomena by estimating the reproducibility of grain-boundary energies that are not employed for potential fitting. Our tensile-loading simulations of a nano specimen show that hydrogen reduces elongation at rupture.