The interactions between rhenium and interstitial-type defects in bulk tungsten: A combined study by molecular dynamics and molecular statics simulations
YC Chen and JZ Fang and LX Liu and WY Hu and C Jiang and N Gao and HB Zhou and GH Lu and F Gao and HQ Deng, JOURNAL OF NUCLEAR MATERIALS, 522, 200-211 (2019).
Tungsten (W) and W-based alloys are the leading candidates for plasma- facing materials (PFMs) in future fusion reactors. However, the high energy neutrons generated in fusion reactions not only result in cascade damages but also cause W transmutation. Both the irradiation defects and transmutation products, mainly rhenium (Re), have serious effects on the service behaviors of W PFMs. In this work, we have systematically investigated the interaction between Re and the self-interstitial atoms, self-interstitial clusters and 112<111> interstitial dislocation loops in bulk W using molecular dynamics and statics simulations. It is found that there is a strong attractive interaction between an interstitial W atom and a substitutional Re atom, forming a Re-W dumbbell that migrates 3-dimentionally due to the low migration and rotation energies. The small SIA clusters strongly bind with both the substitutional Re atoms and an interstitial Re atom (Re-W mixed dumbbell), thus decreasing the mobility of these clusters. The strong attractive interaction between a Re atom and a 112<111> interstitial dislocation loop occurs when the Re atom is located at the core of the loop, and also, their interaction distance along <111> direction is large. The mobility of the 112<111> interstitial dislocation loop decreases progressively with increasing Re concentration. (C) 2019 Elsevier B.V. All rights reserved.
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