Atomistic simulation of 100(001) crack propagation with Cu precipitates in alpha-iron

J Yin and HY Hou and JT Wang and XB Liu and F Xue, INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING, 194, 104519 (2021).

DOI: 10.1016/j.ijpvp.2021.104519

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 alpha-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.

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