α鉄中のらせん転位とプリズマティック転位ループの相互作用における臨界分解せん断応力のモデリング

抄録

Reactor pressure vessel (RPV) steels are known to be embrittled due to the neutron irradiations during the long-term operation of nuclear power plants. The neutron irradiation produces extensive amount of point defects, and finally forms matrix damages as a result of the self-diffusion of the point defects. As one of the matrix damage, prismatic dislocation loops are considered. Therefore, the interaction between prismatic dislocation loops and dislocations must be understood to clarify the role of the prismatic dislocation loop in the embrittlement of RPV steels. In this study, the interaction between prismatic dislocation loops and dislocations is investigated by the molecular dynamics (MD) method using an ANN potential to reveal the interaction mechanism and the critical resolved shear stress (CRSS). The numerical results show that, as a result of the direct interaction between the prismatic dislocation loop and a screw dislocation, a helical dislocation is formed. The increase in the CRSS due to the interaction with the prismatic dislocation loop is then modeled as an equation. It could be found that the prediction of the increase in the CRSS using the derived equation is quantitatively consistent with the MD simulation results.