TY - JOUR
T1 - Defect evolution of neutron irradiated ITER grade tungsten after annealing
AU - Papadakis, Dimitris
AU - Mergia, Konstantina
AU - Manios, Efthymios
AU - Chatzikos, Vasileois
AU - Spilios, Dellis
AU - Bonny, Giovanni
AU - Van Renterghem, Wouter
AU - Terentyev, Dmitry
AU - Chang, Chih-Cheng
AU - Messoloras, Spyros
N1 - Score=10
Funding Information:
This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018, 2019-2020 and 2021-2025 under Grant Agreements Nos. 633053 and 101052200. The views and opinions expressed herein do not necessarily reflect those of the European Commission. The funding from the Hellenic General Secretariat for Research and Innovation for the Greek National Programme of the Controlled Thermonuclear Fusion is acknowledged.
Publisher Copyright:
© 2023
PY - 2023/4
Y1 - 2023/4
N2 - The microstructural evolution of neutron irradiated tungsten (W) after annealing and its correlation with the corresponding mechanical properties provides valuable insight on the defect interactions and their annihilation processes. This would result in the identification of recovery mechanisms, leading to the design of healing
processes and thus, enabling the lifetime extension of fusion reactor components. Within this framework, samples from ITER specification forged W bar were neutron irradiated to a dose of 0.2 displacements per atom (dpa) at 600 .C in the Belgian Material Test Reactor (BR2) and subsequently annealed at 800 and 1000 .C. The evolution of the irradiation induced defects after annealing has been assessed by transmission electron microscopy (TEM), positron annihilation lifetime spectroscopy and electrical resistivity and its effect on the mechanical properties are discussed in terms of Vickers hardness. Neutron irradiation results in the formation of dislocation loops and voids. TEM observations show an increase in the size of both defect types after post irradiation (PI) annealing at both temperatures, accompanied by an initial increase in their density after PI annealing at 800 .C, followed by a subsequent decrease after PI annealing at 1000 .C. The presence of TEM-irresolvable defects of both types is revealed in the as-irradiated state, which is evidenced by the evolution of Vickers hardness, resistivity and positron lifetimes and their correlation after the PI annealing. In the as-irradiated state, as well as after PI annealing at both temperatures, the hardening is dominated by voids.
AB - The microstructural evolution of neutron irradiated tungsten (W) after annealing and its correlation with the corresponding mechanical properties provides valuable insight on the defect interactions and their annihilation processes. This would result in the identification of recovery mechanisms, leading to the design of healing
processes and thus, enabling the lifetime extension of fusion reactor components. Within this framework, samples from ITER specification forged W bar were neutron irradiated to a dose of 0.2 displacements per atom (dpa) at 600 .C in the Belgian Material Test Reactor (BR2) and subsequently annealed at 800 and 1000 .C. The evolution of the irradiation induced defects after annealing has been assessed by transmission electron microscopy (TEM), positron annihilation lifetime spectroscopy and electrical resistivity and its effect on the mechanical properties are discussed in terms of Vickers hardness. Neutron irradiation results in the formation of dislocation loops and voids. TEM observations show an increase in the size of both defect types after post irradiation (PI) annealing at both temperatures, accompanied by an initial increase in their density after PI annealing at 800 .C, followed by a subsequent decrease after PI annealing at 1000 .C. The presence of TEM-irresolvable defects of both types is revealed in the as-irradiated state, which is evidenced by the evolution of Vickers hardness, resistivity and positron lifetimes and their correlation after the PI annealing. In the as-irradiated state, as well as after PI annealing at both temperatures, the hardening is dominated by voids.
KW - Tungsten
KW - Post-irradiation annealing
KW - TEM
KW - Positron annihilation spectroscopy
KW - Electrical resistivity
KW - Hardness
UR - https://ecm.sckcen.be/OTCS/llisapi.dll/open/53603353
U2 - 10.1016/j.fusengdes.2023.113486
DO - 10.1016/j.fusengdes.2023.113486
M3 - Article
SN - 0920-3796
VL - 189
JO - Fusion Engineering & Design
JF - Fusion Engineering & Design
M1 - 113486
ER -