Temperature‐dependent thermodynamic properties of refractory metals: Nonempirical study

1996 ◽  
Vol 104 (22) ◽  
pp. 9075-9078 ◽  
Author(s):  
Genady Davidov ◽  
David Fuks ◽  
Simon Dorfman
Keyword(s):  
Thermodynamic Properties ◽  
Refractory Metals ◽  
Temperature Dependent ◽  
Nonempirical Study

First-Principles Investigation of Phase Stability, Elastic and Thermodynamic Properties in L12 Co3(Al,Mo,Ta) Phase

2017 ◽  
Vol 898 ◽  
pp. 438-445
Author(s):  
Qiang Yao ◽  
Tong Lu ◽  
Qiong Wang ◽  
Yan Wang ◽  
Yu Hong Zhu
Keyword(s):  
Thermodynamic Properties ◽  
Phase Stability ◽  
First Principles ◽  
Linear Thermal Expansion ◽  
Temperature Dependent ◽  
Shear Moduli ◽  
Young’S Moduli ◽  
High Temperature Alloys ◽  
Temperature Dependences ◽  
Significant Temperature

First-principles calculations have been performed to investigate the phase stability, elastic, and thermodynamic properties of Co3(Al,Mo,Ta) with the L12 structure. Calculated elastic constants showed that Co3(Al,Mo,Ta) is mechanically stable and possesses intrinsic ductility. Young’s and shear moduli of polycrystalline Co3(Al,Mo,Ta) were calculated using the Voigt-Reuss-Hill approach. It was found that the shear and Young’s moduli of Co3(Al,Mo,Ta) were smaller than those of Co3(Al,W). States density indicated the existence of covalent-like bonding in Co3(Al,Mo,Ta). Temperature-dependent thermodynamic properties of Co3(Al,Mo,Ta) could be described satisfactorily using the Debye-Grüneisen approach, including entropy, enthalpy, heat capacity and linear thermal expansion coefficient, showing their significant temperature dependences. Furthermore the obtained data could be employed in the modeling of thermodynamic and mechanical properties of Co-based alloys to enable the design of high temperature alloys.

scholarly journals First-principles study on electronic, optic, elastic, dynamic and thermodynamic properties of RbH compound

2015 ◽  
Vol 6 ◽  
pp. A6 ◽  
Author(s):  
Sinem Erden Gulebaglan ◽  
Emel Kilit Dogan ◽  
Mehmet Nurullah Secuk ◽  
Murat Aycibin ◽  
Bahattin Erdinc ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Band Gap ◽  
Lattice Constant ◽  
First Principles ◽  
Density Functional ◽  
Temperature Dependent ◽  
Functional Theory ◽  
Salt Structure ◽  
Elastic Lattice ◽  
Good Agreement

We performed first-principles calculations to obtain the electronic, optical, elastic, lattice-dynamical and thermodynamic properties of RbH compound with rock salt structure. The ground-state properties, i.e., the lattice constant and the band gap were investigated using a plane wave pseudopotential method within density functional theory. The calculated lattice constant, bulk modulus, energy band gap and elastic constants are reported and compared with previous theoretical and experimental results. Our calculated results and the previous results which are obtained from literature are in a good agreement. Moreover, real and imaginary parts of complex dielectric function, reflectivity spectrum, absorption, extinction coefficient and loss function as a function of photon energy and refractive index with respect to photon wavelength were calculated. In addition, temperature dependent thermodynamic properties such as Helmholtz free energy, internal energy, entropy and specific heat have been studied.

Insight into the Structural, Electronic, Elastic, Mechanical, and Thermodynamic Properties of XReO3 (X = Rb, Cs, Tl) Perovskite Oxides: A DFT Study

2019 ◽  
Vol 74 (9) ◽  
pp. 827-836 ◽  
Author(s):  
Song Zhao ◽  
Zhongbin Wei ◽  
Sajad Ahmad Dar
Keyword(s):  
Thermodynamic Properties ◽  
Density Functional ◽  
Local Density ◽  
Perovskite Oxides ◽  
Generalized Gradient ◽  
Temperature Dependent ◽  
Functional Theory ◽  
Melting Temperatures ◽  
Generalized Gradient Approximation ◽  
Insight Into

AbstractIn the present work, perovskite oxides XReO3 (X = Rb, Cs, Tl) have been reported using density functional theory (DFT) for structural, electronic, mechanical, elastic, and thermodynamic properties. Structural optimization has been carried out using local density approximation (LDA) and generalized gradient approximation (GGA) in the scheme of Perdew, Burke, and Ernzerhof. Electronic properties have been calculated using GGA, and all the three materials were found to have metallic nature. From the elastic constants, all the three compounds were found mechanically stable in cubic structure. Poisson’s ratio (ν), Cauchy’s pressure (C12–C44) and Pugh ratio (B/G) present the ductile nature of RbReO3 and TlReO3, whereas CsReO3 was found to establish a brittle nature. These compounds were found to have an elastically anisotropic nature. The calculated melting temperatures were found to be 2851 ± 300, 2814 ± 300, and 2924 ± 300 K, respectively, for XReO3 (X = Rb, Cs, Tl). Using quasi-harmonic Debye approximation, we have calculated the pressure- and temperature-dependent variation in cell volume, bulk modulus, Debye temperature, and specific heat capacity.

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