Vacancy-cluster and off-lattice metal-atom diffusion mechanisms in transition metal carbides

Salehin, Rofiques; Tang, Xiaochuan; Thompson, Gregory B.; Weinberger, Christopher R.

doi:10.1016/j.commatsci.2021.110713

Cited by 6 publications

(1 citation statement)

References 31 publications

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“…For example, the C vacancy migration energy is 4.00 eV in TaC and 3.79 eV in TiC. In addition, vacancy clusters containing one metal vacancy surrounded by six carbon vacancies has the lowest formation energy in group IVB carbides, whereas the vacancy clusters with the lowest formation energy in group VB carbides only contain metal vacancy surrounded by wo carbon vacancies 28 . Both factors will contribute to fewer and smaller vacancy clusters in TaC, and thus the suppressed bubble formation.…”

Section: Resultsmentioning

confidence: 99%

Effects of transition metal carbide dispersoids on helium bubble formation in dispersion-strengthened tungsten

Saefan

Liu

Lang

et al. 2023

Sci Rep

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The formation of helium bubbles and subsequent property degradation poses a significant challenge to tungsten as a plasma-facing material in future long-pulse plasma-burning fusion reactors. In this study, we investigated helium bubble formation in dispersion-strengthened tungsten doped with transition metal carbides, including TaC, ZrC, and TiC. Of the three dispersoids, TaC exhibited the highest resistance to helium bubble formation, possibly due to the low vacancy mobility in the Group VB metal carbide and oxide phases. Under identical irradiation conditions, large helium bubbles formed at grain boundaries in tungsten, while no bubbles were observed at the interfaces between the carbide dispersoid and tungsten matrix. Moreover, our results showed the interfaces could suppress helium bubble formation in the nearby tungsten matrix, suggesting that the interfaces are more effective in trapping helium as tiny clusters. Our research provided new insights into optimizing the microstructure of dispersion-strengthened tungsten alloys to enhance their performance.

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Section: Resultsmentioning

confidence: 99%