Fracture properties of Reactor Pressure Vessel (RPV) steel have significant effects on its service life and the nuclear safety. In this work, Molecular Dynamic (MD) simulation has been performed to investigate [100](001) crack propagation in α-iron. The influences of temperature and the Cu precipitates on the crack propagation were studied. In the simulation, twinning bands induced by the slipping of partial dislocation were observe. While we increased the simulation temperature or introduced the Cu precipitates to the model, the dislocation cross-slip behavior was observed, which reduced the peak stress and made the crack easier to initially propagate. However, it is revealed from the simulation results that the Cu precipitates resisted the further crack propagation, especially for the Cu precipitates with diameter larger than 3 nm. In addition, the Cu precipitates on the pre-crack plane represent better resistance to crack propagation than other locations. Furthermore, comparing the RPV steel with the copper-containing steel, it is concluded that the smaller size of Cu precipitates and the higher service temperature of RPV steel are the main reason of the embrittlement induced by Cu precipitates.

反应堆压力容器（RPV）钢的断裂性能对其使用寿命和核安全有显着影响。在这项工作中，进行了分子动力学 (MD) 模拟以研究 α-铁中的 [100](001) 裂纹扩展。研究了温度和Cu析出物对裂纹扩展的影响。在模拟中，观察到部分位错滑移引起的孪晶带。当我们提高模拟温度或将 Cu 沉淀物引入模型时，观察到位错交叉滑移行为，这降低了峰值应力并使裂纹更容易最初扩展。然而，模拟结果表明，Cu 析出物阻碍了裂纹的进一步扩展，尤其是对于直径大于 3 nm 的 Cu 析出物。此外，预裂纹平面上的铜沉淀比其他位置表现出更好的抗裂纹扩展能力。此外，将RPV钢与含铜钢进行比较，可以得出结论，Cu析出物的较小尺寸和RPV钢的较高使用温度是Cu析出物引起脆化的主要原因。