Irradiation Hardening and Microstructure Evolution of Ion-irradiated ODS Ferritic Steels

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Volume 4, Issue 7 (July 2007)

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ISSN: 1546-962X
Published Online: 20 July 2007
Page Count: 9

Irradiation Hardening and Microstructure Evolution of Ion-irradiated ODS Ferritic Steels
Yutani, Kentaro
Graduate Student, Graduate School of Energy Science, Kyoto University, Kyoto

Kasada, Ryuta
Research Associates and Professor, Institute of Advanced Energy, Kyoto University, Kyoto

Kishimoto, Hirotatsu
Research Associates and Professor, Institute of Advanced Energy, Kyoto University, Kyoto

Kimura, Akihiko
Research Associates and Professor, Institute of Advanced Energy, Kyoto University, Kyoto

(Received 11 July 2006; accepted 22 June 2007)

Abstract

Irradiation hardening and microstructural change of oxide dispersion strengthened (ODS) ferritic steels were investigated by using the ion-irradiation technique. The material used for the present study was K3 (16C-2W-0.3Ti-4.6Al-0.4Y²O³) ODS ferritic steel for the application to Generation IV concept advanced reactors and fusion reactors. 6.4 MeV Fe³⁺ ions were used to irradiate to the K3 ODS steel by using a 1.7 MeV tandem accelerator. The irradiation temperatures were 300°C and 500°C. The nominal displacement damage rate and total displacement damage were 1×10⁻³ dpa/s and up to 10 dpa at about 600-nm depth from the irradiated surface, respectively. Nano-indentation hardness was evaluated with a Berkovich indenter. After the ion-irradiation at 300°C up to 1 dpa, the normalized nano-indentation hardness (hardness after irradiation/hardness before irradiation) of the K3 ODS steel reached about 1.28 and the value showed no change up to 10 dpa. On the other hand, the ion-irradiation at 500°C up to 10 dpa showed no significant irradiation hardening. TEM observation revealed that dense and fine dislocation loops were formed in the ion-irradiated steels at 300°C, which were probably enough to explain the irradiation hardening.

Keywords:
ODS ferritic steel, irradiation hardening, microstructure, ion-irradiation, nano-indentation

Paper ID: JAI100701
DOI: 10.1520/JAI100701
ASTM International is a member of CrossRef.

Author Title Irradiation Hardening and Microstructure Evolution of Ion-irradiated ODS Ferritic Steels Symposium Effects of Radiation on Materials: 23rd Symposium, 2006-06-15 Committee E10

		Home Journals STPs Manuals Topics Subscriptions/Pricing Digital Library / Journals / Journal of ASTM International (JAI) / Citation Page Volume 4, Issue 7 (July 2007) Click here to download this paper now for $25 PDF (304K) View License Agreement ISSN: 1546-962X Published Online: 20 July 2007 Page Count: 9 Irradiation Hardening and Microstructure Evolution of Ion-irradiated ODS Ferritic Steels Yutani, Kentaro Graduate Student, Graduate School of Energy Science, Kyoto University, Kyoto Kasada, Ryuta Research Associates and Professor, Institute of Advanced Energy, Kyoto University, Kyoto Kishimoto, Hirotatsu Research Associates and Professor, Institute of Advanced Energy, Kyoto University, Kyoto Kimura, Akihiko Research Associates and Professor, Institute of Advanced Energy, Kyoto University, Kyoto (Received 11 July 2006; accepted 22 June 2007) Abstract Irradiation hardening and microstructural change of oxide dispersion strengthened (ODS) ferritic steels were investigated by using the ion-irradiation technique. The material used for the present study was K3 (16C-2W-0.3Ti-4.6Al-0.4Y²O³) ODS ferritic steel for the application to Generation IV concept advanced reactors and fusion reactors. 6.4 MeV Fe³⁺ ions were used to irradiate to the K3 ODS steel by using a 1.7 MeV tandem accelerator. The irradiation temperatures were 300°C and 500°C. The nominal displacement damage rate and total displacement damage were 1×10⁻³ dpa/s and up to 10 dpa at about 600-nm depth from the irradiated surface, respectively. Nano-indentation hardness was evaluated with a Berkovich indenter. After the ion-irradiation at 300°C up to 1 dpa, the normalized nano-indentation hardness (hardness after irradiation/hardness before irradiation) of the K3 ODS steel reached about 1.28 and the value showed no change up to 10 dpa. On the other hand, the ion-irradiation at 500°C up to 10 dpa showed no significant irradiation hardening. TEM observation revealed that dense and fine dislocation loops were formed in the ion-irradiated steels at 300°C, which were probably enough to explain the irradiation hardening. Keywords: ODS ferritic steel, irradiation hardening, microstructure, ion-irradiation, nano-indentation Paper ID: JAI100701 DOI: 10.1520/JAI100701 ASTM International is a member of CrossRef. Author Title Irradiation Hardening and Microstructure Evolution of Ion-irradiated ODS Ferritic Steels Symposium Effects of Radiation on Materials: 23rd Symposium, 2006-06-15 Committee E10