J. Mater. Sci. Technol. ›› 2024, Vol. 197: 17-24.DOI: 10.1016/j.jmst.2024.01.040

Special Issue: Nuclear materials 2024 Iron and steel materials 2024

• Research Article • Previous Articles     Next Articles

Effect of He/dpa ratio on bubble characteristics in Fe9Cr1.5W0.4Si F/M steel during irradiation and annealing

Dewang Cuia,d, Kefei Peia,d, Ziqi Caoa,d, Yipeng Lic,d, Yifan Dinga,d, Yuanming Lib,e, Shichao Liub,e, Guang Rana,d,*   

  1. aCollege of Energy, Xiamen University, Xiamen, 361102, China;
    bScience and Technology on Reactor System Design Technology Laboratory, Chengdu, 610213, China;
    cCollege of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China;
    dFujian Provincial Nuclear Energy Engineering Technology Research Center, Xiamen, 361102, China;
    eNuclear Power Institute of China, Chengdu, 610213, China
  • Received:2023-10-07 Revised:2023-12-29 Accepted:2024-01-08 Published:2024-10-20 Online:2024-10-15
  • Contact: *E-mail address: gran@xmu.edu.cn (G. Ran)

Abstract: The He production rate (i.e., He/dpa) in nuclear reactors strongly affects the degradation of material properties. This is an important but not yet fully understood issue. Here, the effect of He/dpa on bubble characteristics in Fe9Cr1.5W0.4Si ferrite-martensitic (F/M) steel was in situ studied during 400 keV Fe+ and 30 keV He+ dual-beam irradiation at 723 K with three ratios of 100, 500, and 2500 appm He/dpa and subsequent stepwise annealing using transmission electron microscopy (TEM). He/dpa strongly affected the bubble characteristics. During irradiation, the higher the He/dpa, the smaller the size of irradiated bubbles, but the higher their density. However, He/dpa didn't affect the final saturation size of irradiated bubbles for all three cases, which was ∼2.2 nm. During annealing, high He/dpa caused large, immobile, dense polyhedral bubbles with a wider bubble size distribution, while low He/dpa caused small, low-mobility, and relatively low-density spherical bubbles. It was found that the higher the He/dpa ratio, the greater the swelling during irradiation and annealing, and annealing further enhanced the swelling. Moreover, the tunnel structure was first found in body-centered cubic (BCC) F/M steel during in-situ irradiation. The current work provides valuable and potential insights for further understanding the He/dpa effects in materials serving in different nuclear reactors.

Key words: He effect, Ferritic-martensitic steel, He bubble, Ion irradiation, Annealing