A novel displacement cascade driven irradiation creep mechanism in α-zirconium: A molecular dynamics study
(2020) Journal of Nuclear Materials — Vol. 541, p. 152336 (2020)
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- Abstract
- Zirconium alloys used in nuclear reactors undergo irradiation creep, which consists of a visco-plastic deformation activated by irradiation occurring under constant load. However, the fundamental underlying mechanisms have not been unraveled yet. A new high-stress irradiation creep mechanism for recrystallized Zircaloy-4 has recently been proposed based on in situ ion irradiation deformation experiments. A displacement cascade is assumed to induce a direct unpinning of a dislocation from an irradiation defect if the cascade occurs within an effective volume around the pinning point. In the present work, a systematic molecular dynamics study was performed to investigate the effect of a 20 keV cascade occurring near <a>-screw dislocation pinned on an interstitial <a>-loop. The direct release of dislocations by displacement cascades is predicted by the simulations. This release is more likely around the pinning points and with increasing stress, in agreement with experimental observations. The effective volume is roughly estimated for three stress levels equal to 0.89tc, 0.93tc and 0.97tc, with tc.
- Affiliations
Université Paris-Saclay CEA, Service de Recherches Métallurgiques Appliquées Université Paris-Saclay CEA, Service de Recherches de Métallurgie Physique Université Grenoble-Alpes Science et Ingénierie des Matériaux et Procédés (SIMAP)
Citations
Khiara, N., Onimus, F., Dupuy, L., Kassem, W., Crocombette, J.-P., Pardoen, T., Raskin, J.-P., & Bréchet, Y. (2020). A novel displacement cascade driven irradiation creep mechanism in α-zirconium: A molecular dynamics study. Journal of Nuclear Materials, 541, 152336. https://doi.org/10.1016/j.jnucmat.2020.152336 (Original work published 2020)