TY - JOUR
T1 - Influence of carbon on the evolution of irradiation defects in tungsten
AU - Niu, Yu-Ze
AU - Li, Yu-Hoa
AU - Ren, Qing-Yuan
AU - Terentyev, Dmitry
AU - Ma, Hui-Zhi
AU - Zhou, Hong-Bo
AU - Lu, Guang-Hong
N1 - Score=10
Funding Information:
This research is supported by the National MCF Energy R&D Program with Grant No. 2018YFE0308103 , and the National Natural Science Foundation of China with Grant Nos. 12192281 and 12075022 .
Publisher Copyright:
© 2023 Elsevier B.V.
PY - 2023/6
Y1 - 2023/6
N2 - We have systematically investigated the influence of carbon (C) impurity on the aggregation, migration, and annihilation of neutron irradiation defects as well as the mechanical properties of tungsten (W), based on the object kinetic Monte Carlo (OKMC) calculations in combination with the theoretical models. Interestingly, although C has a strong attraction with both vacancy-type and interstitial-type irradiation defects, the C addition promotes the aggregation of former but inhibits latter in W. On the one hand, due to the weak repulsion of di-vacancy, it is difficult to form vacancy clusters spontaneously. However, the presence of C changes the interaction between vacancies from repulsion to attraction, thus promot- ing their clustering in W and leading to the increase of average size of vacancies cluster. On the other hand, because of the strong attraction, self-interstitial atoms (SIAs) tend to form clusters spontaneously. However, the C addition will slow down the diffusivity of SIAs due to the strong attraction between them, thereby blocking the aggregation of interstitial-type defects. Therefore, the number density of SIA clusters will increase with the increasing of C concentration, but the average size decreases significantly. Besides, the influence of C on the annihilation ratio of neutron irradiation defects is dependent on the temperature, which is mainly because the stability of C-SIA complexes and the migration of vacancies are strongly temperature dependent. Further, it is found that the increment of Vickers hardness in irradiated W at low temperature increases with the increasing of C concentration, which should be attributed to the enhanced effect of C on the retention of irradiation defects. When the C concentration is 2.5–5 appm, the model predictions are consistent with the experimental results. Consequently, although the concen- tration of impurity is extremely low in nuclear materials, it has significant effect on the defect evolution and mechanical properties under irradiation
AB - We have systematically investigated the influence of carbon (C) impurity on the aggregation, migration, and annihilation of neutron irradiation defects as well as the mechanical properties of tungsten (W), based on the object kinetic Monte Carlo (OKMC) calculations in combination with the theoretical models. Interestingly, although C has a strong attraction with both vacancy-type and interstitial-type irradiation defects, the C addition promotes the aggregation of former but inhibits latter in W. On the one hand, due to the weak repulsion of di-vacancy, it is difficult to form vacancy clusters spontaneously. However, the presence of C changes the interaction between vacancies from repulsion to attraction, thus promot- ing their clustering in W and leading to the increase of average size of vacancies cluster. On the other hand, because of the strong attraction, self-interstitial atoms (SIAs) tend to form clusters spontaneously. However, the C addition will slow down the diffusivity of SIAs due to the strong attraction between them, thereby blocking the aggregation of interstitial-type defects. Therefore, the number density of SIA clusters will increase with the increasing of C concentration, but the average size decreases significantly. Besides, the influence of C on the annihilation ratio of neutron irradiation defects is dependent on the temperature, which is mainly because the stability of C-SIA complexes and the migration of vacancies are strongly temperature dependent. Further, it is found that the increment of Vickers hardness in irradiated W at low temperature increases with the increasing of C concentration, which should be attributed to the enhanced effect of C on the retention of irradiation defects. When the C concentration is 2.5–5 appm, the model predictions are consistent with the experimental results. Consequently, although the concen- tration of impurity is extremely low in nuclear materials, it has significant effect on the defect evolution and mechanical properties under irradiation
KW - Carbon
KW - Irradiation defects
KW - Evolution behavior
KW - Tungsten
KW - Object kinetic Monte Carlo
UR - https://ecm.sckcen.be/OTCS/llisapi.dll/open/54720297
U2 - 10.1016/j.jnucmat.2023.154393
DO - 10.1016/j.jnucmat.2023.154393
M3 - Article
SN - 0022-3115
VL - 579
JO - Journal of Nuclear Materials
JF - Journal of Nuclear Materials
M1 - 154393
ER -