The nanoindentation (NI) technique was employed to investigate the hydrogen effect on nanohardness near grain boundary (GB) of a polycrystalline nickel sample in the present work. An increase of nanohardness due to hydrogen segregation at GB was captured by nanoindentation experiments. With a newly developed GB hardening model, the observed hardening effect upon approaching GB in both H free and H charged polycrystalline Ni was explained. By combining the new GB hardening model with the model depicting dislocation transmission across GB, the hydrogen induced energy barrier enhancement was calculated, which can be used in multi-scale modeling of dislocation–GB interaction. The finding of this work is important for understanding hydrogen embrittlement mechanism of polycrystalline metals.

在本工作中，采用纳米压痕 (NI) 技术研究了氢对多晶镍样品晶界附近 (GB) 纳米硬度的影响。纳米压痕实验捕获了由于 GB 处的氢偏析导致的纳米硬度增加。使用新开发的 GB 硬化模型，解释了在无 H 和带 H 的多晶 Ni 中接近 GB 时观察到的硬化效果。通过将新的 GB 硬化模型与描述跨 GB 的位错传输的模型相结合，计算了氢诱导的能量势垒增强，可用于位错-GB 相互作用的多尺度建模。这项工作的发现对于理解多晶金属的氢脆机制很重要。