Self-diffusion of Ti interstitial based point defects and complexes in TiC

Sun, Weiwei; Ehteshami, Hossein; Kent, Paul; Korzhavyi, Pavel A.

doi:10.1016/j.actamat.2018.11.056

Cited by 19 publications

(10 citation statements)

References 50 publications

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“…According to our DFT calculations, the formation energy for the aforementioned defect complex is ~4.44 eV, which is much lower than the formation energy of the Ti interstitial, ~9.46 eV. In addition, our DFT shows that the migration barrier for this Ti defect complex in bulk TiC x is ~0.85 eV, which is consistent with the previous DFT calculations performed by Sun et al ( 38 ), ~0.93 eV. We found that this migration barrier for Ti defect complex in TiC x is dramatically reduced to ~0.07 eV at the interface region (approximately within a distance of three atomic layers from the interface).…”

Section: Resultssupporting

confidence: 91%

“…The displaced Si and Ti interstitials are expected to form interstitial-V C complexes in TiC x . Specifically, previously published DFT calculations ( 38 ) have reported that the existence of V C can significantly reduce the formation energy of Ti interstitials in TiC x , and have shown that Ti interstitials in TiC x prefer to exist as a defect complex, involving two V C and one Ti dumbbell interstitial. According to our DFT calculations, the formation energy for the aforementioned defect complex is ~4.44 eV, which is much lower than the formation energy of the Ti interstitial, ~9.46 eV.…”

Section: Resultsmentioning

confidence: 99%

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Enhancing the phase stability of ceramics under radiation via multilayer engineering

Zhang

et al. 2021

Sci. Adv.

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In metallic systems, increasing the density of interfaces has been shown to be a promising strategy for annealing defects introduced during irradiation. The role of interfaces during irradiation of ceramics is more unclear because of the complex defect energy landscape that exists in these materials. Here, we report the effects of interfaces on radiation-induced phase transformation and chemical composition changes in SiC-Ti3SiC2-TiCx multilayer materials based on combined transmission electron microscopy (TEM) analysis and first-principles calculations. We found that the undesirable phase transformation of Ti3SiC2 is substantially enhanced near the SiC/Ti3SiC2 interface, and it is suppressed near the Ti3SiC2/TiC interface. The results have been explained by ab initio calculations of trends in defect segregation to the above interfaces. Our finding suggests that the phase stability of Ti3SiC2 under irradiation can be improved by adding TiCx, and it demonstrates that, in ceramics, interfaces are not necessarily beneficial to radiation resistance.

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Section: Resultssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Enhancing the phase stability of ceramics under radiation via multilayer engineering

Zhang

et al. 2021

Sci. Adv.

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“…Kong et al 22 revealed that the carbon vacancy is the dominant defect in hexagonal WC. Carbide TiC was chosen by Sun et al 23 to calculate the self‐diffusion of Ti interstitial‐based point defects and complexes. Razumovskiy et al 24 focused on a description of a complex vacancy behavior of the group IVb substoichiometric TMCs TiC, ZrC, and HfC carbides and found a strong tendency toward vacancy clustering in the carbides.…”

Section: Introductionmentioning

confidence: 99%

Intrinsic defects, Mo‐related defects, and complexes in transition‐metal carbide VC: A first‐principles study

et al. 2020

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“…The model of intrinsic point defects that may exist in TMCs normally contains vacancies, substitutions (antisite) and interstitials. Interstitial defect includes octahedral interstitial and tetrahedral interstitial defects depending on the specific structure [32][33][34][35]. Figure 1 shows the models to investigate the effect of all different point defects on Mo 2 C crystal structure, including models with one atom vacancy (Mo vacancy (V Mo ) and C vacancy (V C )), and one atom substitution (Mo substitution (S Mo ) and C substitution (S C )), as well as one atom tetrahedral interstitials (Mo interstitial (I Mo ) and C interstitial (I C )).…”

Section: Resultsmentioning

confidence: 99%

“…Among all the publications related to Mo 2 C, detailed studies on different types of defects in Mo 2 C are limited, which is relevant to both engineering and energy applications. One effective approach is through first-principles calculations, which has been used in studying defects in TMCs, such as monocarbides, including TiC, ZrC and HfC [32][33][34][35]. In this work, supercell structure of Mo 2 C was used to investigate the effects of vacancy, substitution and interstitial defects at different lattice sites.…”

Section: Introductionmentioning

confidence: 99%

Insight into Point Defects and Complex Defects in β-Mo2C and Carbide Evolution from First Principles

et al. 2022

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In this paper, first principles method was adopted to investigate the point defects, Vanadium-related defects and defect combinations (vacancy (V), substitutional (S) and/or interstitial (I)) in molybdenum β-Mo2C and explore the use of first principles calculation data in analysing the link between different carbides and the effects of doping elements. Supercell models with different defect types were established and optimized, and the formation energy data of defects was developed. The structure evolution during the optimization process is analysed in detail to establish the main characteristics of changes and the relevant electronic properties. The data for different types of intrinsic defects and combined defects complexes was developed and key results is analysed. The results show that carbon vacancy (VC) is stable but does not inevitably exist in pure β-Mo2C. Interstitial site II is a very unstable position for any type of atoms (Mo, V and C), and analysis of the structure evolution shows that the atom always moves to the interface area near the interstitial site I between two layers. In particular, a C atom can expand the lattice structure when it exists between the layer interfaces. One type of the defects studied, the substitution of Mo with V (designated as ‘SV-Mo’), is the most stable defect among all single point defects. The data for defect complexes shows that the combination of multiple SV-Mo defects in the super cell being more stable than the combination of other defects (e.g., ‘VMo+IC’, ‘SV-Mo+VC’). The data with increasing SV-Mo in (Mo, V)2C system is developed, and typical data (e.g., formation energy) for Mo-rich carbides and V carbides are correlated and the potential of the data in analysing transition of different carbides is highlighted. The relevance of using first principles calculation data in the studying of V-doping and the complex carbides (V- and Mo-rich carbides) evolution in different materials systems and future focus of continuous work is also discussed.

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Self-diffusion of Ti interstitial based point defects and complexes in TiC

Cited by 19 publications

References 50 publications

Enhancing the phase stability of ceramics under radiation via multilayer engineering

Enhancing the phase stability of ceramics under radiation via multilayer engineering

Intrinsic defects, Mo‐related defects, and complexes in transition‐metal carbide VC: A first‐principles study

Insight into Point Defects and Complex Defects in β-Mo2C and Carbide Evolution from First Principles

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