One-dimensional migration of interstitial clusters in SUS316L and its model alloys under electron irradiation

Abstract

The one-dimensional (1D) migration of interstitial clusters in austenitic stainless steel SUS316L and its model alloys, namely, Fe–18Cr–13Ni, Fe–18Cr–13Ni–0.012C, and Fe–18Cr–13Ni–1.7Mn (mass %), was examined using in situ observation by high-voltage electron microscopy. Such 1D migration was confirmed to occur along the ⟨110⟩ direction at irregular intervals in all these alloys under 1250-kV electron irradiation at room temperature. The frequency of 1D migration was found proportional to electron beam intensity, and was about 1/10 that in high-purity iron under the same irradiation intensity. The distance of 1D migration in the four alloys was less than 10 nm, which was much shorter than that in high-purity iron. No clear difference in the frequency or distance of 1D migration was observed among the four alloys, suggesting that minor solute/impurity elements have no apparent effect on 1D migration in SUS316L.

Keywords:

• point defects
• irradiation effects
• electron irradiation
• TEM

Acknowledgements

We are grateful to Messrs. E. Aoyagi and Y. Hayasaka of the High Voltage Electron Microscopy Center at Tohoku University for technical support in the electron irradiation experiments. We also thank Dr. T. Ashino, Dr. K. Takada, and Mr. H. Shimada of the Analytical Research Core for Advanced Materials, Institute for Materials Research, Tohoku University for conducting the impurity analysis of the specimens. This work was supported in part by a Grant-in-Aid for Scientific Research by the Ministry of Education, Culture, Sports, Science, and Technology of Japan (No. 21560868) and by a sponsorship of the JNES open application research project for enhancing the basis of nuclear safety (JNES: Japan Nuclear Energy Safety Organization).