TY - JOUR
T1 - Change in nanoindentation hardness of polycrystalline tungsten irradiated with Fe ions or electrons by hydrogen gas charging
AU - Sato, Koichi
AU - Kasada, Ryuta
AU - Kiyohara, Atsushi
AU - Hirabaru, Masashi
AU - Nakano, Kenichi
AU - Yabuuchi, Kiyohiro
AU - Hatakeyama, Masahiko
AU - Xu, Qiu
N1 - Funding Information:
The authors thank Prof. H. Matsunaga, Dr. M. Nakamura, and staff of HYDROGENIUS, Kyushu University for carrying out the hydrogen charging. This study was supported by Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Numbers JP18K03584 , JP18K04774 , and JP21H01068 . This study was carried out, in part, under the visiting Researcher's Program of the Institute for Integrated Radiation and Nuclear Science, Kyoto University. This study was performed under the GIMRT Program of the Institute for Materials Research, Tohoku University (Proposal Nos. 19K0028 and 20K0039 ). This study was supported by the Joint Usage/Research Program on Zero-Emission Energy Research, Institute of Advanced Energy, Kyoto University ( ZE31B-29 and ZE2020B-27 ).
Funding Information:
The authors thank Prof. H. Matsunaga, Dr. M. Nakamura, and staff of HYDROGENIUS, Kyushu University for carrying out the hydrogen charging. This study was supported by Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Numbers JP18K03584, JP18K04774, and JP21H01068. This study was carried out, in part, under the visiting Researcher's Program of the Institute for Integrated Radiation and Nuclear Science, Kyoto University. This study was performed under the GIMRT Program of the Institute for Materials Research, Tohoku University (Proposal Nos. 19K0028 and 20K0039). This study was supported by the Joint Usage/Research Program on Zero-Emission Energy Research, Institute of Advanced Energy, Kyoto University (ZE31B-29 and ZE2020B-27).
Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2022/3
Y1 - 2022/3
N2 - The effects of hydrogen atoms on the hardnesses of unirradiated, ion-irradiated, and electron-irradiated polycrystalline tungsten samples were investigated using nanoindentation tests. The bulk equivalent hardnesses of the unirradiated and electron-irradiated tungsten samples did not change upon hydrogen charging. The bulk equivalent hardness of the ion-irradiated tungsten increased upon the hydrogen charging. The number of hydrogen atoms trapped at dislocation loops was very small. We estimated that the hydrogen occupancy in vacancy clusters was 0.24−0.45 (in the case of tri-vacancies, the number of hydrogen atoms trapped per vacancy (H/V) is 1.04−1.95). Because of the irradiation temperature of 573 K, the density and size of irradiation-induced defects did not change during hydrogen charging at 543 K. Therefore, the hardening was mainly caused by an increase of approximately 8 − 11% in the obstacle strength α of vacancy clusters containing hydrogen atoms. The ion-irradiated area hardened upon the hydrogen charging and changed the configuration of the pile-up. Observation of the dislocation structure is required to clarify the mechanism of hardening caused by hydrogen charging.
AB - The effects of hydrogen atoms on the hardnesses of unirradiated, ion-irradiated, and electron-irradiated polycrystalline tungsten samples were investigated using nanoindentation tests. The bulk equivalent hardnesses of the unirradiated and electron-irradiated tungsten samples did not change upon hydrogen charging. The bulk equivalent hardness of the ion-irradiated tungsten increased upon the hydrogen charging. The number of hydrogen atoms trapped at dislocation loops was very small. We estimated that the hydrogen occupancy in vacancy clusters was 0.24−0.45 (in the case of tri-vacancies, the number of hydrogen atoms trapped per vacancy (H/V) is 1.04−1.95). Because of the irradiation temperature of 573 K, the density and size of irradiation-induced defects did not change during hydrogen charging at 543 K. Therefore, the hardening was mainly caused by an increase of approximately 8 − 11% in the obstacle strength α of vacancy clusters containing hydrogen atoms. The ion-irradiated area hardened upon the hydrogen charging and changed the configuration of the pile-up. Observation of the dislocation structure is required to clarify the mechanism of hardening caused by hydrogen charging.
KW - Electron irradiation
KW - Hardness
KW - Hydrogen
KW - Ion irradiation
KW - Nanoindentation
KW - Tungsten
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U2 - 10.1016/j.jnucmat.2021.153483
DO - 10.1016/j.jnucmat.2021.153483
M3 - Article
AN - SCOPUS:85121902933
VL - 560
JO - Journal of Nuclear Materials
JF - Journal of Nuclear Materials
SN - 0022-3115
M1 - 153483
ER -