Effect of interstitial <inline-formula><tex-math id="Z-20200513225448">\begin{document}${\left\langle {100} \right\rangle }$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20200317_Z-20200513225448.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20200317_Z-20200513225448.png"/></alternatives></inline-formula> dislocation loop on expansion of micro-crack in body centered cubic iron investigated by molecular dynamics method
Authors: Liang Jin-Jie , Gao Ning , Li Yu-Hong ,   School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China,   Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China,   Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266237, China
Published: December 2020

The interactions between the energetic particles and atoms in materials would result in the atomic displacements and the associated radiation defects. The interstitial dislocation loop, as one of the primary radiation defects, is formed by the clustering of the supersaturated self-interstitial atoms from the displacement damages in body centered cubic (bcc) iron based materials. The radiation hardening, embrittlement, swelling, creep, etc. are generally related to these loops and their interactions with other defects. In addition, the irradiation would also result in the formation of the micro-cracks from the surface of the materials and also from the interface of grains, precipitates, and gas-bubbles inside the materials, which would result in the irradiation assisted stress corrosion crack (IASCC). Therefore, to understand the interaction between interstitial dislocation loop and micro-crack under the irradiation, is one of key steps to understand the underlying mechanism of IASCC. In this work, the interaction between interstitial dislocation loop and micro-crack is simulated by molecular dynamics method on an atomic scale. The distance, relative position between them and radius of dislocation loop, as the main factors affecting their interactions, are studied to explore the underlying reason for inducing the micro-crack to expand on the slip plane. The simulation results indicate that when the interaction between them dominates the whole process with the distance between them within the critical value, the dislocation network containing the <inline-formula><tex-math id="Z-20200522122407-1">\begin{document}$ \langle 100 \rangle $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20200317_Z-20200522122407-1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20200317_Z-20200522122407-1.png"/></alternatives></inline-formula> and 1/2<inline-formula><tex-math id="Z-20200522122407-2">\begin{document}$ \langle 111 \rangle $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20200317_Z-20200522122407-2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20200317_Z-20200522122407-2.png"/></alternatives></inline-formula> segments, would interact with the crack tip to inhibit the crack from expanding through the pinning effect. When the size of loop is different, the pining effect would be available only when the interaction between loop core and crack tip dominates with the distance between them within the critical value. All these results provide new understanding for further exploring the IASCC under irradiation.