Grain boundaries (GBs) relaxation is a promising and effective strategy to improving GB stability or stabilizing nanocrystalline metals. However, previous studies mainly focused on nanocrystalline pure metals and GB behaviors therein, without considering the role of foreign atoms such as impurity or alloying atoms in GB relaxation. In this work, the shear-strain induced structural relaxation of pure Cu Σ3 [110](112) symmetric tilt GBs (STGBs), and the effects of foreign elements (Fe and Ni) and temperature on the GB relaxation were investigated in detail by molecular dynamics method. The results show that shear strain can trigger the structural relaxation of pure, Fe- and Ni-containing Cu GBs by the emission of Shockley partial dislocations from Cu GBs. Both Fe and Ni have impediment effects on the shear-strain induced GB relaxation, though the content of Fe or Ni atom (0.00165 at.%) is quite low in the GB model. The temperature cannot trigger GB relaxation independently within the considered temperature range, but play a positive role in the shear-strain induced structural relaxations of pure, Fe- and Ni-containing Cu Σ3 [110](112) STGBs. Our work might gain new insights into the mechanically induced GB relaxation in nanocrystalline copper and could be beneficial for improving the stability of Cu GBs.

晶界（GBs）弛豫是提高GB稳定性或稳定纳米晶金属的一种有前途且有效的策略。然而，先前的研究主要集中在纳米晶体纯金属及其中的GB行为，而没有考虑杂质原子或合金原子等外来原子在GB弛豫中的作用。在这项工作中，详细研究了剪切应变引起的纯CuΣ3[110]（112）对称倾斜GBs（STGBs）的结构弛豫，以及杂质（Fe和Ni）和温度对GB弛豫的影响，方法是：分子动力学方法。结果表明，剪切应变可以通过从铜GBs中释放Shockley部分位错来触发纯的，含铁和含镍的铜GBs的结构弛豫。Fe和Ni都对剪切应变引起的GB弛豫有阻碍作用，尽管在GB模型中，Fe或Ni原子的含量（0.00165 at。％）非常低。温度不能在所考虑的温度范围内独立触发GB弛豫，但在剪切应变引起的纯铁，含铁和含镍CuΣ3[110]（112）STGB的结构弛豫中起积极作用。我们的工作可能会获得有关纳米晶铜中机械诱导的GB弛豫的新见解，并且可能有助于提高Cu GBs的稳定性。