Thermoelastic properties of random alloys from first-principles theory

Huang, Lunmei; Vitos, Levente; Kwon, S. K.; Johansson, Börje; Ahuja, Rajeev

doi:10.1103/physrevb.73.104203

Cited by 55 publications

(35 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The calculations based on this effect do not reproduce the temperature range over which the effects are measured for C 44 of bcc niobium. 34 Our results show that the additional smearing of electronic features by phonons at high temperature ͑broaden-ing the electron states themselves, rather than just their occupations͒ are important to understand the temperature dependence of phonons and elastic constants in these materials. The adiabatic EPI induces a significant additional smearing, in some sense increasing the effective temperature.…”

Section: A Elastic Moduli and Phononsmentioning

confidence: 99%

“…Firstprinciples electronic structure calculations identified the effect of band filling on the bulk modulus and shear moduli in V and Nb alloys, in agreement with experimental alloying trends. [34][35][36][37][38][39][40] However, previous interpretations considered only the smearing of electron occupation numbers by the Fermi-Dirac distribution at high temperature. The calculations based on this effect do not reproduce the temperature range over which the effects are measured for C 44 of bcc niobium.…”

Section: A Elastic Moduli and Phononsmentioning

confidence: 99%

“…[34][35][36][37] Anomalous temperature dependencies have been reported for elastic constants of bcc Nb-and V-based alloys, in particular for the shear constant C 44 . [38][39][40][41] For pure V, C 44 softens normally below about 500 K, then stiffens from 500 K to about 1600 K, and finally reverts to a normal softening above 1600 K to melting.…”

Section: A Elastic Moduli and Phononsmentioning

confidence: 99%

See 2 more Smart Citations

Electron-phonon interactions and high-temperature thermodynamics of vanadium and its alloys

et al. 2008

View full text Add to dashboard Cite

Inelastic neutron scattering was used to measure the phonon densities of states ͑DOSs͒ for pure V and solid solutions of V with 6 to 7at% of Co, Nb, and Pt, at temperatures from 10 K to 1323 K. Ancillary measurements of heat capacity and thermal expansion are reported on V and V-7at%Co and used to help identify the different sources of entropy. Pure V exhibits an anomalous anharmonic stiffening of phonons with increasing temperature. This anharmonicity is suppressed by Co and Pt, but not by isoelectronic Nb solutes. The changes in phonon frequency with alloying and with temperature both correlate to the decrease in electron density of states ͑DOS͒ at the Fermi level as calculated using density functional theory. The effects of both temperature and alloying can be understood in terms of an adiabatic electron-phonon interaction ͑EPI͒, which broadens sharp features in the electron DOS. These results show that the adiabatic EPI can influence the phonon thermodynamics at temperatures exceeding 1000 K, and that thermal trends of phonons may help assess the strength of the EPI.

show abstract

Section: A Elastic Moduli and Phononsmentioning

confidence: 99%

Section: A Elastic Moduli and Phononsmentioning

confidence: 99%

Section: A Elastic Moduli and Phononsmentioning

confidence: 99%

See 1 more Smart Citation

Electron-phonon interactions and high-temperature thermodynamics of vanadium and its alloys

et al. 2008

View full text Add to dashboard Cite

show abstract

“…Nowadays, CPA is the most effective alloy theory for calculating electronic structure in multi-component random solid solutions [24][25][26][27][28], despite of the single-site nature of the CPA limiting its applicability to system with insignificant short-range order and local lattice relaxation effects. It has been proven that using the EMTO-CPA method can obtain the structural energy differences related to the lattice distortion in complex alloys of arbitrary number of components and compositions [29][30][31][32][33][34].…”

Section: Methodsmentioning

confidence: 99%

Ab Initio Predicted Alloying Effects on the Elastic Properties of AlxHf1−xNbTaTiZr High Entropy Alloys

Tian

2015

Coatings

View full text Add to dashboard Cite

Abstract:Using ab initio alloy theory, we investigate the equilibrium bulk properties and elastic mechanics of the single bcc solid-solution AlxHf1−xNbTaTiZr (x = 0-0.7, 1.0) high entropy alloys. Ab initio predicted equilibrium volume is consistent with the available experiment. We make a detailed investigation of the alloying effect of Al and Hf on the equilibrium volume, elastic constants and polycrystalline elastic moduli. Results imply that the partial replacement Hf with Al increases the stability of the bcc phase and decreases the ductility of the AlxHf1−xNbTaTiZr HEAs. The inner ductility of Al0.4Hf0.6NbTaTiZr is predicted by the calculations of ideal tensile strength.

show abstract

“…The temperature dependence of the elastic constants was calculated for T =7000 K as described in Ref. [26].…”

Section: Computational Detailsmentioning

confidence: 99%

Thermo-physical properties of body-centered cubic iron–magnesium alloys under extreme conditions

Kádas

Ahuja

Johansson

et al. 2011

Solid State Communications

Self Cite

View full text Add to dashboard Cite

This is an author produced version of a paper published in Solid State Communications. This paper has been peer-reviewed but does not include the final publisher proof-corrections or journal pagination. AbstractUsing density functional theory formulated within the framework of the exact muffin-tin orbitals method, we investigate the thermo-physical properties of body-centered cubic (bcc) iron-magnesium alloys, containing 5 and 10 atomic % Mg, under extreme conditions, at high pressure and high temperature. The temperature effect is taken into account via the Fermi-Dirac distribution of the electrons. We find that at high pressures pure bcc iron is dynamically unstable at any temperature, having a negative tetragonal shear modulus (C ′ ). Magnesium alloying significantly increases C ′ of Fe, and bcc Fe-Mg alloys become dynamically stable at high temperature. The electronic structure origin of the stabilization effect of Mg is discussed in details. We show that the thermo-physical properties of a bcc Fe-Mg alloy with 5% Mg agree well with those of the Earth's inner core as provided by seismic observations.

show abstract

Thermoelastic properties of random alloys from first-principles theory

Cited by 55 publications

References 39 publications

Electron-phonon interactions and high-temperature thermodynamics of vanadium and its alloys

Electron-phonon interactions and high-temperature thermodynamics of vanadium and its alloys

Ab Initio Predicted Alloying Effects on the Elastic Properties of AlxHf1−xNbTaTiZr High Entropy Alloys

Thermo-physical properties of body-centered cubic iron–magnesium alloys under extreme conditions

Contact Info

Product

Resources

About