Influence of nanochannel structure on helium-vacancy cluster evolution and helium retention

JOURNAL OF NUCLEAR MATERIALS

卷:527

Article

Qin, Wenjing^1,2,3,4  Jin, Shuoxue⁵  Cao, Xingzhong⁵  Wang, Yongqiang⁶  Peres, Paula⁷  Choi, Seo-Youn⁷  Jiang, Changzhong^1,2,3  Ren, Feng^1,2,3 

[1] Wuhan Univ, Ctr Ion Beam Applicat, Sch Phys & Technol, Wuhan 430072, Hubei, Peoples R China

[2] Wuhan Univ, Ctr Electron Microscopy, Wuhan 430072, Hubei, Peoples R China

[3] Wuhan Univ, Hubei Nucl Solid Phys Key Lab, Wuhan 430072, Hubei, Peoples R China

[4] Hunan Normal Univ, Synerget Innovat Ctr Quantum Effects & Applicat, Sch Phys & Elect, Key Lab Low Dimens Quantum Struct & Quantum Contr, Changsha 410081, Hunan, Peoples R China

[5] Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China

[6] Los Alamos Natl Lab, Mat Sci & Technol Div, Los Alamos, NM 87545 USA

[7] Cameca SA, 29 Quai Gresillons, F-92230 Gennevilliers, France

关键词: Tungsten;    Nanochannel;    Vacancy-type defects;    He-retention;    Hardness;   

DOI  :  10.1016/j.jnucmat.2019.151822

来源: Elsevier

【 摘 要 】

In the fusion reactors, plasma facing materials (PFMs) will be bombarded by large amounts of energetic particles, including helium (He) atoms. These metal-insoluble He atoms are prone to self-trapping or are trapped by vacancies, dislocation cores or grain boundaries, aggregating to form high concentration He bubbles which leads to serious degradation of the PFMs' properties. Studying the initial stages of He-defect interactions becomes increasingly important because it not only helps us understand the formation mechanism of He bubbles but also provides insight to help design new irradiation-resistant PFMs. In this work, we used the positron annihilation Doppler broadening spectroscopy (DBS) and secondary ion mass spectrometry (SIMS) to explore the evolutions of the interactions between vacancy-type defects and He and the retention of He in the nanochannel W film irradiated with 190 keV He+ ions to different fluences under different temperatures. It is found that the presence of a nanochannel structure accelerates the release of He from the film even at low irradiation fluences, and the release of He is significantly enhanced at higher fluences, thus inhibiting or delaying the formation of large He-vacancy clusters in the nanochannel W film. Both irradiation fluence and temperature have significant influence on the formation and evolution of He-vacancy clusters, and the evolution of these microstructure also causes hardness changes. (C) 2019 Elsevier B.V. All rights reserved.

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