Investigation of Helium Behavior in RAFM Steel by Positron Annihilation Doppler Broadening and Thermal Desorption Spectroscopy

• Published in: Materials Vol. 11; no. 9; p. 1523
• Main Authors: Shen, Zhenyu, Guo, Liping, Zhang, Weiping, Jin, Shuoxue, Cao, Xingzhong, Long, Yunxiang, Wei, Yaxia
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 24.08.2018; MDPI
• Subjects: Binding energy; Bubbles; Clusters; Desorption; Dual phase steels; Experiments; Ferritic stainless steels; Fluence; Helium; Helium ions; High energy physics; Irradiation; Martensitic stainless steels; Positron annihilation; positron annihilation spectroscopy; Positrons; reduced-activation ferritic/martensitic steel; S parameters; Spectrum analysis; Steel; Thermal desorption spectroscopy; helium; positron annihilation spectroscopy; reduced-activation ferritic/martensitic steel; thermal desorption spectroscopy
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma11091523

The behavior of helium in reduced-activation ferritic/martensitic steels was investigated systematically with positron annihilation Doppler broadening measurement and thermal desorption spectroscopy. Specimens were irradiated with helium ions with different energies to various fluences at different temperatures. A threshold fluence was observed above which the rate of formation and growth of helium bubbles dramatically increased. Irradiation at higher temperature could suppress the formation and growth of He V clusters with low binding energies and enhance that of helium bubbles and He V clusters with high binding energies. Different changes of S parameters were observed in various depth after the irradiation temperature was increased from 523 K to 723 K. Irradiation of 18 keV-He⁺ enhanced the growth of He V clusters and helium bubbles compared with 100 keV-He⁺ irradiation. A possible mechanism is discussed.