First-principles energy and vibration spectrum simulations of Cr/V interacting with H in W-based alloy in a fusion reactor |
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Authors: | Song Gao Zhen-Hong Dai Quan-Fu Han Fang Ding |
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Affiliation: | 1. Department of Physics, Yantai University, Yantai, China;2. Department of Physics, Beihang University, Beijing, China;3. Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China |
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Abstract: | We perform first-principles total energy and vibration spectrum calculations to study the effect of Cr/V on the H formation and diffusion at temperature range 300–2100 K in dilute W–Cr/W–V alloy. Temperature and H chemical potential are two important factors to affect the H formation energy and migrating energy. The H formation energy referring to the static/temperature-dependent H chemical potential decreases/increases with the temperature. At each given temperature, the presence of Cr in W reduces the H formation energy, while the existence of V in W has little effect on the H formation energy. The diffusion energy barrier and pre-exponential factor strongly depend on the temperature and increase with the temperature from 300 to 2100 K. Both Cr and V additions in W has a large consequences on H migrating energy. The energy barriers at any given temperature can be reduced by ~0.05 and 0.10 eV in W–Cr and W–V alloys, respectively. The current study reveals that vibration free energy plays a decisive role in the formation energy and migrating energy of H with the temperature, while the thermal expansion energy has little influence on the H formation energy and migrating energy with the temperature. |
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Keywords: | Tungsten-based alloys fusion reactor hydrogen formation and diffusion temperature and H chemical potential first-principles calculations |
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