Are Nanophase Grain Boundaries Anomalous?

Stern, E. A.; Siegel, R.W.; Newville, Matthew; Sanders, P.G.; Haskel, D.

doi:10.1103/physrevlett.75.3874

Cited by 113 publications

(66 citation statements)

References 19 publications

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“…The pair-distribution functions, nearest-neighbor coordinations, and bond-angle distributions in the interfacial regions of n-SiC are found to be similar to those of bulk amorphous SiC. These results are consistent with neutron and X-ray diffraction measurements, and also with electron microscopy studies [49].…”

Section: Nanophase Silica and Silicon Carbidesupporting

confidence: 79%

Multiresolution algorithms for massively parallel molecular dynamics simulations of nanostructured materials

Kalia

Campbell

Chatterjee

et al. 2000

Computer Physics Communications

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Section: Nanophase Silica and Silicon Carbidesupporting

confidence: 79%

Multiresolution algorithms for massively parallel molecular dynamics simulations of nanostructured materials

Kalia

Campbell

Chatterjee

et al. 2000

Computer Physics Communications

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“…structure is similar to that in coarser-grained materials [20][21][22][23][24][25][26][27][28][29][30], while others proposed a frozen 'gaslike' structure of the grain boundaries in which the atomic arrangement at interfacial region lacks short-or long-range order [31][32][33]. In nanocrystalline solids a large fraction of atoms are located near grain boundaries.…”

Section: Nanostructurementioning

confidence: 92%

Nanocrystalline materials and coatings

Tjong

Chen

2004

Materials Science and Engineering: R: Reports

842

345

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In recent years, near-nano (submicron) and nanostructured materials have attracted increasingly more attention from the materials community. Nanocrystalline materials are characterized by a microstructural length or grain size of up to about 100 nm. Materials having grain size of $0.1 to 0.3 mm are classified as submicron materials. Nanocrystalline materials exhibit various shapes or forms, and possess unique chemical, physical or mechanical properties. When the grain size is below a critical value ($10-20 nm), more than 50 vol.% of atoms is associated with grain boundaries or interfacial boundaries. In this respect, dislocation pile-ups cannot form, and the Hall-Petch relationship for conventional coarse-grained materials is no longer valid. Therefore, grain boundaries play a major role in the deformation of nanocrystalline materials. Nanocrystalline materials exhibit creep and super plasticity at lower temperatures than conventional micro-grained counterparts. Similarly, plastic deformation of nanocrystalline coatings is considered to be associated with grain boundary sliding assisted by grain boundary diffusion or rotation. In this review paper, current developments in fabrication, microstructure, physical and mechanical properties of nanocrystalline materials and coatings will be addressed. Particular attention is paid to the properties of transition metal nitride nanocrystalline films formed by ion beam assisted deposition process. #

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“…The intergrain regions could also be amorphous in nature, which would clearly produce an attenuation of the EXAFS signal and a reduction of the peak amplitudes in the Fourier transform. However, the qualitative effect in EXAFS is the same as that produced by the simple reduction of crystallite size, and care has to be taken over the sample preparation and measurement procedures as on the EXAFS analysis to separate the two effects, 29,32 as illustrated in the current controversy over the level of disorder in the intergrain regions in the case of nanocrystalline metals. [32][33][34][35] In this respect, Qi et al reported in their EXAFS study of nanocrystalline YSZ that the cation-cation (Zr-Zr) coordination number is reduced due to the large number of cations near the surface (with fewer nearest neighbors) when the grain size decreases.…”

Section: A Xanes: Qualitative Analysismentioning

confidence: 99%

XANES and EXAFS study of the local order in nanocrystalline yttria-stabilized zirconia

et al. 2013

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The local order around Zr and Y atoms of nanocrystalline yttria-stabilized zirconia (YSZ) powders with different grain sizes has been investigated by x-ray absorption spectroscopies. The samples were prepared by means of mechanical alloying with or without subsequent sintering treatment and also by milling commercial YSZ. Our study is motivated by the interest in the electrical properties of grain boundaries and the controversy about the level of disorder in the intergrain regions in nanocrystalline YSZ. The x-ray absorption near edge structure (XANES) analysis indicates that the local order of all the sintered samples is independent of the grain size. This is confirmed by the analysis of the extended x-ray absorption fine structure, which points out also that, in contrast to that found in sintered samples, the local order around the cation in the samples milled without further sintering treatment extends only to the first coordination shell. Finally, the results of ab initio Zr K-edge XANES calculations lead us to conclude that the observed changes of the shape of the white line are not related to a phase transformation but reflects the short-range order present in the as-milled samples.

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Are Nanophase Grain Boundaries Anomalous?

Cited by 113 publications

References 19 publications

Multiresolution algorithms for massively parallel molecular dynamics simulations of nanostructured materials

Multiresolution algorithms for massively parallel molecular dynamics simulations of nanostructured materials

Nanocrystalline materials and coatings

XANES and EXAFS study of the local order in nanocrystalline yttria-stabilized zirconia

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