Plasma and Fusion Research

Volume 17, 1205105 (2022)

Rapid Communications

Size and Temperature Dependence of the Point Defect Binding Free Energy to Defect Clusters in bcc Fe
Yoshiyuki WATANABE, Kazunori MORISHITA1), Takashi NOZAWA and Hiroyasu TANIGAWA
National Institutes for Quantum Science and Technology (QST), Rokkasho, Aomori 039-3212, Japan
Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
(Received 13 July 2022 / Accepted 30 September 2022 / Published 24 November 2022)


Size and temperature dependence of the point defect binding free energy has numerically evaluated for self-interstitial atom (SIA) clusters and vacancy clusters in bcc Fe by using continuum models based on thermodynamics and linear elasticity. The estimated binding free energy of SIAs to SIA-clusters is much higher than that of vacancies to vacancy clusters, indicating that SIA-clusters are more thermally stable than vacancy clusters. For relatively small clusters, the estimated binding free energy at 0 K is comparably consistent with atomistic calculation data; and then, the SIA binding free energy at 850 K is averagely about 35% lower than that at 0 K, while the vacancy binding free energy is about 6% lower; which may remarkably affect the formation kinetics of those defect clusters under irradiation. These kinds of information will be one of the basic parameters for a theoretical model of the microstructural evolution of Fe-based materials in the nuclear fusion DEMO environment.


structural material, irradiation damage, microstructural evolution, defect energetics, numerical analysis

DOI: 10.1585/pfr.17.1205105


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