Core element effects on dislocation nucleation in 3C–SiC: Reaction pathway analysis

Sun, Yu; Izumi, Satoshi; Sakai, Shinsuke; Yagi, Kuniaki; Nagasawa, Hiroyuki

doi:10.1016/j.commatsci.2013.05.055

Cited by 11 publications

(15 citation statements)

References 34 publications

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“…As estimated in this study, the local equilibrium concentration of Y at the surface is approximately C eq s = 46% when the concentration of bulk is assumed to be C b = 18.2% (10YSZ). Under this equilibrium condition, our MD results predict that the oxygen diffusion coefficients at 46 atom% Y-segregated surface (D oxy s, 46 ) is approximately equal to that at 18.2 atom% YSZ bulk (D oxy b,18.2 ). In addition, as shown in Fig.…”

Section: Oxygen Diffusion At Surfacementioning

confidence: 80%

“…The intermediate images are provided by connecting the two endpoints by linear interpolation. The convergence is determined when the potential force on each replica vertical to the path becomes less than 1.0 × 10 −5 eV/Å [45,46]. The activation energies E i→j for cation hopping from the ith layer to the jth layer have been computed for the top six layers denoted as i(= 1, .…”

Section: Cation Defect Migration Energymentioning

confidence: 99%

“…This analysis is performed using an NEB method [44], which we have previously applied to the barrier measurement of defect nucleation in various solid systems [45,46]. The input to the NEB method is an initial estimation of the energy pathway composed of a string of 13 images.…”

Section: Cation Defect Migration Energymentioning

confidence: 99%

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Atomistic study of segregation and diffusion of yttrium and calcium cations near electrolyte surfaces in solid oxide fuel cells

Sun

Hara

2015

Journal of the European Ceramic Society

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Segregation behaviors of yttrium (Y) and calcium (Ca) cation dopant species near zirconia (1 1 1) surfaces have been investigated utilizing atomistic simulations. The results reveal that surface segregation of both species can be achieved when the density of cation and oxygen vacancies near the surface is relatively high compared to the bulk. Comparing Y with Ca, the local equilibrium concentration at the surface of Ca is estimated to be lower than that of Y; however, Ca is kinetically much easier to diffuse from bulk to the surface than Y. The analysis of in-plane cation and oxygen diffusion at Y-or Ca-rich surfaces shows that the cation diffusivity is enhanced with increasing Ca-concentration at the surface, whereas oxygen diffusivity is inhibited. This tendency is more remarkable than that of the Y-rich surface, suggesting that Ca segregation has a greater negative impact than Y segregation on electrolyte performance in solid oxide fuel cells.

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Section: Oxygen Diffusion At Surfacementioning

confidence: 80%

Section: Cation Defect Migration Energymentioning

confidence: 99%

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Atomistic study of segregation and diffusion of yttrium and calcium cations near electrolyte surfaces in solid oxide fuel cells

Sun

Hara

2015

Journal of the European Ceramic Society

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“…Increase of defect atoms occurs almost at the same time in each sub-lattice, but, after the pop-in (d > 3.06 nm), the number of defects atom of C is more than the number of defects atom of Si. This difference is caused by the fact that the dislocation core is different in Si and C [13]. Nevertheless, both distribution of defect atoms (those shown in Fig.…”

Section: Structure Analysis By Cnamentioning

confidence: 96%

Molecular Dynamics Study on Ductile Behavior of SiC during Nanoindentation

et al. 2016

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In order to clarify the plastic deformation mechanism of silicon carbide in cubic phase (3C-SiC), molecular dynamics (MD) simulations are performed on the nanoindentation using a spherical indenter. Transition from elastic deformation to plastic deformation has been confirmed by the phenomenon called pop-in in the load-displacement curves during nanoindentation. Dislocations on {1 1 1} slip planes are found during indentation. In order to analyze internal defects, common neighbor analysis (CNA) is slightly modified so that it is suitable for the analysis of slips of zinc-blend structure. In our method, the CNA is applied separately to sub-lattice of Si or C in the same SiC. By this method, structural changes are confirmed in a region with the shape of square pyramid when the pop-in behavior occurs. By measuring the atomic distances along the region of misalignment, it was confirmed that there is certainly atomic sliding by crystalline slip. Furthermore, it is found that, with increase of loading, dislocation loops spread along {1 1 1} slip planes.

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“…Therefore, atomic simulation with more atoms based on empirical potential is needed. Sun et al (2013) showed that the Si-core dislocation has lower activation energy and may result in athermal strains during glide-set partial nucleation from sharp corners. This conclusion agrees with the previously-mentioned experimental data.…”

Section: Introductionmentioning

confidence: 99%

Reaction pathway analysis for differences in motion between C-core and Si-core partial dislocation in 3C-SiC

Yang

Izumi

Muranaka

et al. 2015

Mechanical Engineering Journal

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Reaction pathway analysis was carried out to investigate the activation energy barriers of Shockley partial dislocation mobility in 3C-SiC. For each partial dislocation, there are two types of dislocations according to which kind of atom, Si or C, comprises the core edge of the dislocation line. In this paper, the partial dislocation is simulated by Vashishta potential functions. Moreover, the activation energy of kink pair nucleation and kink migration are investigated by reaction pathway analysis. The dependence of the activation energy on the driving shear stress is also discussed. The results show that during kink migration, 30° partial dislocations have a lower activation energy barrier than 90° partial dislocation. And, C-core partial dislocations have a higher activation energy barrier than Si-core dislocations for both degrees of partial dislocations during kink migration and nucleation. This conclusion is consistent with the experimental result that Si-core dislocations migrate more readily than C-core dislocations. Furthermore, we found that partial dislocations with larger distance between the dangling bond atoms along the dislocation line have higher activation energy barriers. Based our calculation results, we propose new models to account for the morphological differences in the dislocation lines.

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Core element effects on dislocation nucleation in 3C–SiC: Reaction pathway analysis

Cited by 11 publications

References 34 publications

Atomistic study of segregation and diffusion of yttrium and calcium cations near electrolyte surfaces in solid oxide fuel cells

Atomistic study of segregation and diffusion of yttrium and calcium cations near electrolyte surfaces in solid oxide fuel cells

Molecular Dynamics Study on Ductile Behavior of SiC during Nanoindentation

Reaction pathway analysis for differences in motion between C-core and Si-core partial dislocation in 3C-SiC

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