Elasticity and lattice vibrational properties of transparent polycrystalline yttrium–aluminium garnet: Experiments and pair potential calculations

Djémia, Philippe; Têtard, Florent; Bouamama, Kh.; Charron, Eric; Tétard, D.; Rabinovitch, Y.

doi:10.1016/j.jeurceramsoc.2007.02.216

Cited by 12 publications

(6 citation statements)

References 31 publications

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“…The elastic constants c 11 , c 12 , and c 44 are 349, 116, and 116 GPa, respectively; and the elastic modulus and bulk modulus are 291 and 193 GPa, respectively. Our results are in better agreement with the experimental ones when compared to those obtained from atomic simulations . The calculated static dielectric constant is 3.4 for YAG and the direct band gap is 4.3 eV.…”

Section: Resultssupporting

confidence: 88%

Mechanism of Intrinsic Point Defects and Oxygen Diffusion in Yttrium Aluminum Garnet: First‐Principles Investigation

Liu

Wang

et al. 2012

J. Am. Ceram. Soc.

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Formation of intrinsic point defect in yttrium aluminum garnet (YAG) is comprehensively investigated using first‐principles calculations. We showed that the defect formation energies of intrinsic point defects closely depend on the possible values of chemical potentials of Y, Al, and O. Both YAl16(a) anti‐site defect, oxygen vacancy VO, and interstitial Oi might be the preferred defect species when chemical potentials of Y, Al, and O vary in different areas. The O‐related defects are also important intrinsic point defects in YAG and deserve to be further examined. The oxygen self‐diffusion are investigated and we found that energy barrier of oxygen diffusion is enhanced and decreased by neighboring YAl16(a) and AlY anti‐site defects, respectively. The results are used to explain the mechanism of experimental observations that Al2O3 excess speeds up oxygen diffusion and that Y2O3 excess suppresses oxygen diffusion in YAG.

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Section: Resultssupporting

confidence: 88%

Mechanism of Intrinsic Point Defects and Oxygen Diffusion in Yttrium Aluminum Garnet: First‐Principles Investigation

Liu

Wang

et al. 2012

J. Am. Ceram. Soc.

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“…The shear modulus, bulk modulus, and Young's modulus of YAG, YAP, and YAM are summarized in Table , together with experimental data of YAG and computational data of YAP for comparison . The presently calculated elastic moduli of YAG and YAP are well consistent with those reported in references.…”

Section: Resultssupporting

confidence: 79%

Theoretical Prediction of Elastic Stiffness and Minimum Lattice Thermal Conductivity of Y₃Al₅O₁₂, YAlO₃ and Y₄Al₂O₉

et al. 2012

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Combining Clarke's model with first‐principles calculation of average sound velocity, the minimum lattice thermal conductivities (κmin) of Y3Al5O12 (YAG), YAlO3 (YAP) and Y4Al2O9 (YAM) are predicted to be 1.59, 1.61, and 1.10 W·(m·K)−1, respectively. The weak Y–O polyhedra provide “weak zones” that scattering phonons and lead to the low κmin of ternary Y–Al–O compounds. In addition, the extremely low κmin of YAM is attributed to its higher levels of local disorder of crystal structure and weaker chemical bonding compared with those of YAG and YAP. Inspired by theoretical predictions, dense and phase‐pure YAM is synthesized and the experimental thermal conductivity is only 1.56 W·(m·K)−1at 1273 K. Finally, YAM is highlighted as a potential thermal barrier material for its low thermal conductivities at temperatures from 473 to 1273 K.

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“…Recent works have demonstrated that yttrium aluminates are promising candidates for TBCs due to their superior high temperature stability, and mechanical and thermal properties [5,6]. At high temperatures, yttrium aluminum garnet (i.e., Y 3 Al 5 O 12 , YAG) is stable with Al 2 O 3 [5], which is the thermally grown oxide formed on Ni-based superalloys.…”

Section: Introductionmentioning

confidence: 99%

Theoretical prediction on mechanical and thermal properties of a promising thermal barrier material: Y4Al2O9

Zhou

Xiang

et al. 2015

J Adv Ceram

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Abstract:The mechanical and thermal properties of Y 4 Al 2 O 9 were predicted using a combination of first-principles and chemical bond theory (CBT) calculations. Density functional theory (DFT) computations were performed for the structural, mechanical, and thermal properties, and the results were confirmed by chemical bond theory. Based on the calculated equilibrium crystal structure, heterogeneous bonding nature has been revealed, i.e., Al-O bonds are stronger than Y-O bonds. Low second-order elastic constants c 44 , c 55 , and c 66 demonstrate the low shear deformation resistance. Low G/B ratio suggests that Y 4 Al 2 O 9 is a damage tolerant ceramic. Y 4 Al 2 O 9 shows anisotropy in elastic behavior based on the discussion of direction dependence of Young's modulus. The hardness is predicted to be 10.2 GPa from calculated elastic moduli. The thermal expansion coefficient (TEC) calculated by chemical bond theory is 7.51×10 6 K 1. In addition, the minimum thermal conductivity of Y 4 Al 2 O 9 is estimated to be 1.13 W·m 1 ·K 1, and the thermal conductivity decreases with temperature as 1305.6/T.

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Elasticity and lattice vibrational properties of transparent polycrystalline yttrium–aluminium garnet: Experiments and pair potential calculations

Cited by 12 publications

References 31 publications

Mechanism of Intrinsic Point Defects and Oxygen Diffusion in Yttrium Aluminum Garnet: First‐Principles Investigation

Mechanism of Intrinsic Point Defects and Oxygen Diffusion in Yttrium Aluminum Garnet: First‐Principles Investigation

Theoretical Prediction of Elastic Stiffness and Minimum Lattice Thermal Conductivity of Y₃Al₅O₁₂, YAlO₃ and Y₄Al₂O₉

Theoretical prediction on mechanical and thermal properties of a promising thermal barrier material: Y4Al2O9

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Elasticity and lattice vibrational properties of transparent polycrystalline yttrium–aluminium garnet: Experiments and pair potential calculations

Cited by 12 publications

References 31 publications

Mechanism of Intrinsic Point Defects and Oxygen Diffusion in Yttrium Aluminum Garnet: First‐Principles Investigation

Mechanism of Intrinsic Point Defects and Oxygen Diffusion in Yttrium Aluminum Garnet: First‐Principles Investigation

Theoretical Prediction of Elastic Stiffness and Minimum Lattice Thermal Conductivity of Y3Al5O12, YAlO3 and Y4Al2O9

Theoretical prediction on mechanical and thermal properties of a promising thermal barrier material: Y4Al2O9

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Theoretical Prediction of Elastic Stiffness and Minimum Lattice Thermal Conductivity of Y₃Al₅O₁₂, YAlO₃ and Y₄Al₂O₉