The structural stability, elastic constants and electronic structure of Al–Sr intermetallics by first-principles calculations

The lattice parameters, structural stability, mechanical properties, hardness and electronic structure of WCoB with Cr alloying were investigated by using first-principles calculations. The Cr atom was selected to replace 0, 1, 2, 3, 4 Co atoms in WCoB crystal and 0, 1, 2 Co atoms in W2CoB2 crystal. The calculated cohesive energy and formation enthalpy showed that all structures can retain good structural stability with different Cr doping content. The calculated mechanical properties showed Cr doping will decrease the shear modulus, Young’s modulus, bulk modulus and hardness, but increase the ductility. The larger number of valence electrons of Cr led to the increasing of bond covalence and population. According to the electronic structures analysis, the nonmetal–metal hybridization and metal–metal interactions contributed to relatively high toughness.

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First-Principles Investigation of Structural Stability, Mechanical, Anisotropic, and Thermodynamic Properties of CeT2Al20 Intermetallics

Zeitschrift für Naturforschung A ◽

10.1515/zna-2018-0265 ◽

2018 ◽

Vol 73 (12) ◽

pp. 1157-1167 ◽

Cited By ~ 1

Author(s):

He Ma ◽

Xiaoyou Li ◽

Wei Jiang ◽

Xudong Zhang

Keyword(s):

High Temperature ◽

Thermodynamic Properties ◽

Thermodynamic Parameters ◽

Structural Stability ◽

Elastic Constants ◽

First Principles ◽

Elastic Moduli ◽

Formation Enthalpy ◽

First Principles Calculations ◽

Acoustic Velocities

AbstractFirst-principles calculations were carried out to explore the structural stability, elastic moduli, ductile or brittle behaviour, anisotropy, dynamical stability, and thermodynamic properties of pure Al and CeT2Al20 (T = Ti, V, Cr, Nb, and Ta) intermetallics. The calculated formation enthalpy and phonon frequencies confirm that these intermetallics satisfy the conditions for structural stability. The elastic constants Cij, elastic moduli B, G, and E, and the hardness Hv indicate these intermetallics have higher hardness and the better resistance against deformation than pure Al. The values of Poisson’s ratio (v) and B/G indicate that CeT2Al20 intermetallics are all brittle materials. The anisotropic constants and acoustic velocities confirm that CeT2Al20 intermetallics are all anisotropic, but CeV2Al20, CeNb2Al20, and CeTa2Al20 are nearly isotropic. Importantly, the calculated thermodynamic parameters show that CeT2Al20 intermetallics exhibit better thermodynamic properties than pure Al at high temperature.

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First-Principles Calculations of the Elastic Properties of the Nickel-Based L12 Intermetallics

MRS Proceedings ◽

10.1557/proc-408-557 ◽

1995 ◽

Vol 408 ◽

Author(s):

D. Iotova ◽

N. Kioussis ◽

S. P. Lim ◽

S. Sun ◽

R. Wu

Keyword(s):

Electronic Structure ◽

Total Energy ◽

Ab Initio ◽

Elastic Properties ◽

Elastic Constants ◽

First Principles ◽

Anisotropy Factor ◽

Full Potential ◽

First Principles Calculations ◽

Linear Muffin Tin Orbital

AbstractThe elastic constants of the L12-type ordered nickel-based intermetallics Ni3X (X = Mn, Al, Ga, Si, Ge), have been calculated by means of ab initio total-energy electronic structurecalculations based on the full-potential linear-muffin-tin-orbital (FLMTO) method. Theorigins in the electronic structure of the variation of the elastic constants, bulk and shearmoduli are investigated across the series, and the effects of the anisotropy of bonding chargedensity on the shear anisotropy factor and the degree of ductility is discussed.

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