Prediction of structural, electronic and elastic properties of Y2Ti2O7 and Y2TiO5

Jiang, Yong; Smith, J. R.; Odette, G.R.

doi:10.1016/j.actamat.2009.10.061

Cited by 104 publications

(38 citation statements)

References 31 publications

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“…Otherwise, the materials are expected to deform in a ductile manner with a low G/B value. This relation has been extensively accepted and applied not only to metal but also to high-strength materials [25,26,27]. In principles, the covalent materials (such as diamond and c-BN) have the highest hardness but they are obviously brittle with a larger Pugh modulus ratio.…”

Section: Model and Resultsmentioning

confidence: 99%

Modeling hardness of polycrystalline materials and bulk metallic glasses

et al. 2011

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Though extensively studied, hardness, defined as the resistance of a material to deformation, still remains a challenging issue for a formal theoretical description due to its inherent mechanical complexity. The widely applied Teter's empirical correlation between hardness and shear modulus has been considered to be not always valid for a large variety of materials. Here, inspired by the classical work on Pugh's modulus ratio, we develop a theoretical model which establishes a robust correlation between hardness and elasticity for a wide class of materials, including bulk metallic glasses, with results in very good agreement with experiment. The simplified form of our model also provides an unambiguous theoretical evidence for Teter's empirical correlation.

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Section: Model and Resultsmentioning

confidence: 99%

Modeling hardness of polycrystalline materials and bulk metallic glasses

et al. 2011

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“…Extensive a Author to whom correspondence should be addressed; Electronic mail: lianj@rpi.edu experimental and theoretical efforts are currently underway in order to understand the scientific principles that govern the phase stability of Y-Ti-O nanoclusters upon radiation and thermal annealing. 13 17 The analysis of electronic structures including density of state, valence electron charge density and electron localization function (ELF) indicated strong ionic features for oxide bonds with some degree of covalency in the Ti-O bonds.…”

Section: Introductionmentioning

confidence: 99%

First principles investigation of structural, electronic, elastic and thermal properties of rare-earth-doped titanate Ln2TiO5

et al. 2012

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Systematic first-principles calculations based on density functional theory were performed on a wide range of Ln2TiO5 compositions (Ln = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy and Y) in order to investigate their structural, elastic, electronic, and thermal properties. At low temperature, these compounds crystallize in orthorhombic structures with a Pnma symmetry, and the calculated equilibrium structural parameters agree well with experimental results. A complete set of elastic parameters including elastic constants, Hill's bulk moduli, Young's moduli, shear moduli and Poisson's ratio were calculated. All Ln2TiO5 are ductile in nature. Analysis of densities of states and charge densities and electron localization functions suggests that the oxide bonds are highly ionic with some degree of covalency in the Ti-O bonds. Thermal properties including the mean sound velocity, Debye temperature, and minimum thermal conductivity were obtained from the elastic constants

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“…Our results from a careful study of the frequency of detecting orthorhombic Y 2 TiO 5 or fcc Y 2 energies of these phases have been evaluated to be À36.9 eV per formula unit of Y 2 Ti 2 O 7 (À3560 kJ mol À1 ) and À27.7 eV per formula unit of Y 2 TiO 5 (À2670 kJ mol À1 ), respectively [51]. This suggests ultimately that the formation of Y 2 Ti 2 O 7 should be thermodynamically favoured over Y 2 TiO 5.…”

Section: Discussionmentioning

confidence: 99%

Effect of Ti and Cr on dispersion, structure and composition of oxide nano-particles in model ODS alloys

et al. 2015

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a b s t r a c tThree model ODS alloys (Fe-0.3Y 2 O 3 , Fe-0.2Ti-0.3Y 2 O 3 and Fe-14Cr-0.2Ti-0.3Y 2 O 3 ) were prepared by ball milling and then hot extrusion to study the effect of Ti and Cr on the size, distribution, crystal structure and composition of the nano-oxide particles. All alloys were characterized by high resolution transmission electron microscopy (HRTEM), atom probe tomography (APT) and synchrotron-X-ray diffraction (S-XRD) to determine the distribution, structure and composition of the oxide nanoparticles samples. The median particle sizes were 9.6 nm, 7.7 nm and 3.7 nm for the Fe-Y 2 O 3 , Fe-Ti-Y 2 O 3 and Fe-Cr-Ti-Y 2 O 3 alloys, respectively, so the presence of Ti resulted in a significant reduction in oxide particle diameter and the addition of Cr gave a further reduction in size. In the Fe-0.3Y 2 O 3 alloy, the particles are found to be bcc Y 2 O 3 , whereas in the other two alloys (Fe-Ti-0.3Y 2 O 3 and Fe-Cr-Ti-Y 2 O 3 ), the oxide particles were found to be structurally consistent with both orthorhombic Y 2 TiO 5 and fcc Y 2 Ti 2 O 7 . Detailed APT studies showed Cr shells around oxide particles of all sizes in the Fe-Cr-Ti-Y 2 O 3 alloy, that a range of cluster compositions are present and that the particle chemistry varies with cluster size. We show that the addition of Cr has a strong effect on both the size and stoichiometry of the particles.

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Prediction of structural, electronic and elastic properties of Y2Ti2O7 and Y2TiO5

Cited by 104 publications

References 31 publications

Modeling hardness of polycrystalline materials and bulk metallic glasses

Modeling hardness of polycrystalline materials and bulk metallic glasses

First principles investigation of structural, electronic, elastic and thermal properties of rare-earth-doped titanate Ln2TiO5

Effect of Ti and Cr on dispersion, structure and composition of oxide nano-particles in model ODS alloys

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