Abstract We studied grain boundary (GB) self-diffusion in body-centered cubic iron using ab initio calculations and molecular dynamics simulations with various interatomic potentials. A combination of different models allowed us to determine the principal characteristics of self-diffusion along different types of GBs. In particular, we found that atomic self-diffusion in symmetric tilt GBs is mostly driven by self-interstitial atoms. In contrast, in general GBs atoms diffuse predominantly via an exchange mechanism that does not involve a particular defect but is similar to diffusion in a liquid. Most observed mechanisms lead to a significant enhancement of self-diffusion along GBs as compared to diffusion in the bulk. The results of simulations are verified by comparison with available experimental data.

中文翻译：

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不同原子模型下铁晶界自扩散的研究

摘要 我们使用从头算计算和具有各种原子间势的分子动力学模拟研究了体心立方铁中的晶界 (GB) 自扩散。不同模型的组合使我们能够确定沿不同类型 GB 的自扩散的主要特征。特别是，我们发现对称倾斜 GB 中的原子自扩散主要由自填隙原子驱动。相比之下，一般而言，GBs 原子主要通过不涉及特定缺陷但类似于液体中的扩散的交换机制扩散。与本体中的扩散相比，大多数观察到的机制导致沿 GB 的自扩散显着增强。通过与可用的实验数据进行比较来验证模拟结果。