TY - JOUR
T1 - Contributions of Ni-content and irradiation temperature to the kinetic of solute cluster formation and consequences on the hardening of VVER materials
AU - Courilleau, Camille
AU - Radiguet, Bertrand
AU - Chaouadi, Rachid
AU - Stergar, Erich
AU - Duplessi, Arnaud
AU - Pareige, Philippe
N1 - Score=10
Funding Information:
GENESIS is supported by the Région Haute-Normandie, the Métropole Rouen Normandie, the CNRS via LABEX EMC and the French National Research Agency as a part of the program “Investissements d'avenir” with the reference ANR-11-EQPX-002, The authors acknowledge the financial support of the SCK CEN Academy.
Publisher Copyright:
© 2023 Elsevier B.V.
PY - 2023/11
Y1 - 2023/11
N2 - The study of solute clusters induced by neutron irradiation is fundamental to the understanding of the embrittlement phenomena of Reactor Pressure Vessel (RPV) steels. In this paper, the influence of Ni-content and irradiation temperature on these cluster formation are investigated using atom probe tomography. VVER 1000-BM (base metal) and 1000-W (weld) steels were chosen for their high Ni content of 1.2 and 1.7 at%, respectively. They were irradiated up to doses of 0.28 dpa at two temperatures (265 and 300 ◦C). The irradiations were performed at SCK CEN in the BR2 reactor. After irradiation, Mn, Ni and Si rich clusters were observed. A careful study of their composition indicates that these clusters actually contain iron. Moreover, the evolution of Fe cluster concentration with the dose indicates a constant supply of solutes throughout the irradiation thanks to the flux coupling. With increasing dose, both the cluster size and number density increase. The effect of temperature has to be dissociated from that of Ni content. Both of them result in an increase of the cluster number density at a given dose. The irradiation temperature has a more pronounced effect than chemical composition (mainly Ni effect). This can be explained by the fact that more matrix damage is produced at lower irradiation temperature. The influence of Ni on cluster number density is significantly higher at the lower temperature. All these observations support the hypothesis of radiation-induced segregation, even if a thermodynamic contribution to solute clustering cannot be excluded, in particular in the higher Ni steel irradiated at low temperature. In all cases, the yield strength increases proportionally to the volume fraction of radiation-induced defects (√(Vf)).
AB - The study of solute clusters induced by neutron irradiation is fundamental to the understanding of the embrittlement phenomena of Reactor Pressure Vessel (RPV) steels. In this paper, the influence of Ni-content and irradiation temperature on these cluster formation are investigated using atom probe tomography. VVER 1000-BM (base metal) and 1000-W (weld) steels were chosen for their high Ni content of 1.2 and 1.7 at%, respectively. They were irradiated up to doses of 0.28 dpa at two temperatures (265 and 300 ◦C). The irradiations were performed at SCK CEN in the BR2 reactor. After irradiation, Mn, Ni and Si rich clusters were observed. A careful study of their composition indicates that these clusters actually contain iron. Moreover, the evolution of Fe cluster concentration with the dose indicates a constant supply of solutes throughout the irradiation thanks to the flux coupling. With increasing dose, both the cluster size and number density increase. The effect of temperature has to be dissociated from that of Ni content. Both of them result in an increase of the cluster number density at a given dose. The irradiation temperature has a more pronounced effect than chemical composition (mainly Ni effect). This can be explained by the fact that more matrix damage is produced at lower irradiation temperature. The influence of Ni on cluster number density is significantly higher at the lower temperature. All these observations support the hypothesis of radiation-induced segregation, even if a thermodynamic contribution to solute clustering cannot be excluded, in particular in the higher Ni steel irradiated at low temperature. In all cases, the yield strength increases proportionally to the volume fraction of radiation-induced defects (√(Vf)).
KW - Atom probe tomography (APT)
KW - RPV steel
KW - Neutron irradiation
KW - Irradiation hardening
KW - Solute cluster
KW - Atom probe tomography
UR - http://www.scopus.com/inward/record.url?scp=85165191826&partnerID=8YFLogxK
U2 - 10.1016/j.jnucmat.2023.154616
DO - 10.1016/j.jnucmat.2023.154616
M3 - Article
SN - 0022-3115
VL - 585
JO - Journal of Nuclear Materials
JF - Journal of Nuclear Materials
M1 - 154616
ER -