In the present work, the deformation mechanisms of face-centred cubic (fcc) Fe–C single crystal with nanovoid containing hydrogen at various contents are investigated by molecular dynamics (MD) tensile simulations. The microstructural evolution of the supercell without H reveals that the plastic deformation mechanism is fcc→bcc→hcp continuous martensitic transformation. For the supercell containing 2 at% H, the mechanical response and plastic deformation mechanism are similar to those of the supercell without H. The difference is that bcc martensite nucleation is accompanied by dislocation nucleation, which indicates that a small amount of H addition will promote dislocation slip. When the H content reaches 5 at%, the dislocation slip enhanced by H completely overcomes the martensitic transformation and becomes the main plastic deformation mechanism. By analysing the per-atom potential energy of H atoms and Fe atoms, it is found that the potential energy of H atoms near the dislocation line and on the slip plane will increase, which may reduce the lattice resistance of dislocation slip. Moreover, the addition of H increases the average potential energy of fcc Fe atoms, which results in the reduction in Fe atomic binding, thus increasing the dislocation mobility. The dislocation slip causes localized plasticity on the nanovoid surface, which promotes the expansion of the nanovoid and leads to hydrogen embrittlement. The martensitic transformation and dislocation slip are prone to nucleation at the edge of the nanovoid, which indicates that in practical situations, void defects with sharp corners could induce premature plastic deformation in fcc crystals.

在本工作中，通过分子动力学（MD）拉伸模拟研究了面心立方（fcc）Fe–C单晶的纳米空隙中含有不同含量的氢的变形机理。没有H的超级电池的微观结构演变表明，塑性变形机制是fcc→bcc→hcp连续马氏体转变。对于含2 at％H的超级电池，其力学响应和塑性变形机制与不含H的超级电池相似。不同之处在于bcc马氏体成核伴随位错成核，这表明少量的H加入将促进脱位滑移。当H含量达到5 at％时，H增强的位错滑移完全克服了马氏体相变，成为主要的塑性变形机制。通过分析H原子和Fe原子的每原子势能，发现位错线附近和滑移平面上的H原子的势能会增加，这可能会降低位错滑移的晶格电阻。此外，H的添加增加了fcc Fe原子的平均势能，这导致Fe原子结合的减少，从而增加了位错迁移率。位错滑移引起纳米空隙表面上的局部可塑性，这促进了纳米空隙的膨胀并导致氢脆化。马氏体相变和位错滑移在纳米空隙的边缘易于成核，