Calculation of elastic constants of 4d transition metals

Louail, L.; Maouche, D.; Roumili, A.; Sahraoui, F. Ali

doi:10.1016/j.matlet.2004.04.033

Cited by 101 publications

(39 citation statements)

References 29 publications

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“…Q ∥ and D 0∥ are the activation energy and pre-exponential factor of diffusion within the basal plane, respectively; D ⊥ /D ∥ is the diffusion anisotropy ratio; Q and D 0 are the activation energy and pre-exponential factor of bulk diffusion. The GGA for the exchange and correlation functional was chosen because it is more accurate for evaluating bulk properties such as lattice constants, elastic constants, and cohesive energies 12,13 when compared to the local density approximation (LDA). 14 Both exchange and correlation functionals underestimate the vacancy formation energy relative to experiments.…”

Section: Methodsmentioning

confidence: 99%

Diffusion anisotropy of poor metal solute atoms in hcp-Ti

Scotti

Mottura

2015

The Journal of Chemical Physics

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Atom migration mechanisms influence a wide range of phenomena: solidification kinetics, phase equilibria, oxidation kinetics, precipitation of phases, and high-temperature deformation. In particular, solute diffusion mechanisms in α-Ti alloys can help explain their excellent high-temperature behaviour. The purpose of this work is to study self- and solute diffusion in hexagonal close-packed (hcp)-Ti, and its anisotropy, from first-principles using the 8-frequency model. The calculated diffusion coefficients show that diffusion energy barriers depend more on bonding characteristics of the solute rather than the size misfit with the host, while the extreme diffusion anisotropy of some solute elements in hcp-Ti is a result of the bond angle distortion.

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Section: Methodsmentioning

confidence: 99%

Diffusion anisotropy of poor metal solute atoms in hcp-Ti

Scotti

Mottura

2015

The Journal of Chemical Physics

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“…13 These wide ranges of interesting applications have lead to much efforts that have been devoted to this fascinating material. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] In the past, a number of studies mainly focus on cubic d phase of TaN by the various methods [14][15][16][17][18][19] and also synthesized by diverse methods, [20][21][22] calculations show very high bulk modulus (above 328 GPa) and suggest that TaN is in cubic d phase with high hardness. Compared to the cubic phase, the e and h phases have not been studied deeply.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, it is essential for many practical applications, such as load deflection, thermoelastic stress, and fracture toughness. 29 Therefore, an explicit determination of its elastic properties as a function of pressure is essential, and will have important guidable significances to accelerate the synthesis of TaN.…”

Section: Introductionmentioning

confidence: 99%

Structure and mechanical properties of tantalum mononitride under high pressure: A first-principles study

Chang

Zhao

Zhou

et al. 2012

Journal of Applied Physics

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The structure and mechanical properties of tantalum mononitride (TaN) are investigated at high pressure from first-principles using the plane wave pseudopotential method within the local density approximation. Three stable phases were considered, i.e., two hexagonal phases (e and h) and a cubic d phase. The obtained equilibrium structure parameters and ground state mechanical properties are in excellent agreement with the experimental and other theoretical results. A full elastic tensor and crystal anisotropy of the ultra-incompressible TaN in three stable phases are determined in the wide pressure range. Results indicated that the elastic properties of TaN in three phases are strongly pressure dependent. And the hexagonal h-TaN is the most ultraincompressible among the consider phases, which suggests that the h phase of TaN is a potential candidate structure to be one of the ultraincompressible and hard materials. By the elastic stability criteria, it is predicted that h-TaN is not stable above 53.9 GPa. In addition, the calculated B/G ratio indicated that the e and d phases possess brittle nature in the range of pressure from 0 to 100 GPa. While h phase is brittleness at low pressure (below 8.2 GPa) and is strongly prone to ductility at high pressure (above 8.2 GPa). The calculated elastic anisotropic factors for three phases of TaN suggest that they are elastically highly anisotropic and strongly dependent on the propagation direction.

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“…The elastic constants provide valuable information about the bonding characteristic between adjacent atomic planes and the anisotropic character of the bonding and structural stability [18,19].…”

Section: Introductionmentioning

confidence: 99%

Effect of temperature dependence ultrasonic velocities and attenuation of GaP nanowires

Yadawa¹

2016

J Theor Appl Phys

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The higher order elastic constants of the hexagonal wurtzite crystal structure of GaP nanowires have been evaluated using Lennard-Jones potential model at room temperature. The ultrasonic velocity increases with the temperature along particular orientation with the unique axis of crystals. Temperature variation of the thermal relaxation time and Debye average velocities is also calculated along the same orientation. The temperature dependency of the ultrasonic properties is discussed in correlation with elastic, thermal and electrical properties. It has been found that the thermal conductivity is the main contributor to the behaviour of ultrasonic attenuation as a function of temperature and the responsible cause of attenuation is phonon-phonon interaction. The mechanical properties of GaP nanowires at low temperature are better than at room temperature, because at low temperature it has low ultrasonic velocity and ultrasonic attenuation. A particularly interesting case is GaP, which is the only (Ga, In)-V semiconductor with an indirect gap in the bulk phase, and are indispensable in modern microelectronic industries.

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Calculation of elastic constants of 4d transition metals

Cited by 101 publications

References 29 publications

Diffusion anisotropy of poor metal solute atoms in hcp-Ti

Diffusion anisotropy of poor metal solute atoms in hcp-Ti

Structure and mechanical properties of tantalum mononitride under high pressure: A first-principles study

Effect of temperature dependence ultrasonic velocities and attenuation of GaP nanowires

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