Elastic Constants of Single Crystals of the bcc Transition Elements V, Nb, and Ta

Bolef, D. I.

doi:10.1063/1.1735933

Cited by 218 publications

(36 citation statements)

References 18 publications

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“…The lattice parameters are 2.89 Å for NiAl and 3.04 Å for V, which are in good agreement with previous studies [47][48][49][50]. Elastic constants are a basic mechanical quantity describing the stiffness of the material when strains are applied.…”

Section: Bulk Propertiessupporting

confidence: 90%

The Adhesive Properties of Coherent and Semicoherent NiAl/V Interfaces Within the Peierls-Nabarro Model

Linghu

Wang

et al. 2016

Crystals

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Abstract:The work of adhesion and the interface energy of NiAl/V coherent interface systems have been investigated using first-principles methods. The adhesion of the Ni-terminated interface is larger than the Al-terminated interface. The difference in charge density and the density of states show that the Ni-terminated interface is dominated by metallic bonds, and the Al-terminated interface is dominated by metallic and covalent bonds. To account for the effects of misfit dislocations on the semicoherent interfaces, the Peierls-Nabarro model combined with generalized stacking fault energy is employed to determine the interface energy. It is found that misfit dislocations can reduce the adhesion of the interface, and the reduction increases with the maximum of the restoring force.

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Section: Bulk Propertiessupporting

confidence: 90%

The Adhesive Properties of Coherent and Semicoherent NiAl/V Interfaces Within the Peierls-Nabarro Model

Linghu

Wang

et al. 2016

Crystals

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“…The incident energy was 55 meV and the detector coverage allowed for momentum transfers between 0.5 and 9 A ÿ1 at zero energy transfer. The FWHM energy resolution was 1:1 meV at 40 meV positive energy transfer, increasing to Reference [13]. VOLUME 93, NUMBER 18 2:8 meV at the elastic line.…”

mentioning

confidence: 71%

Negative Entropy of Mixing for Vanadium-Platinum Solutions

Delaire

Swan-Wood²,

Fultz³

2004

Phys. Rev. Lett.

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The phonon densities of states for pure vanadium and the solid solutions V-6.25% Ni, Pd, Pt were determined from inelastic neutron scattering measurements. The solute atoms caused a large stiffening of the phonons, resulting in large, negative vibrational entropies of mixing. For V-6.25%Pt, the negative vibrational entropy of mixing exceeds the conventional positive chemical entropy of mixing. This negative total entropy of mixing should extend to lower concentrations of Pt, and the effect on the bcc solvus line is discussed. The experimental data were inverted to obtain interatomic force constants by using a Born-von Ká rmán model with an iterative optimization algorithm. The stiffening of bonds responsible for the decrease of entropy was found to occur mainly in first-nearest-neighbor solute-host bonds, and correlates in part with the solute metallic radius. DOI: 10.1103/PhysRevLett.93.185704 PACS numbers: 64.75.+g, 61.12.-q, 63.70.+h Mixing creates structural disorder, so the entropy of a mixed system is expected to be larger than an unmixed system. The well-known configurational entropy of mixing in the point approximationis always positive (c is concentration, 0 < c < 1). Its contribution to the free energy F E ÿ TS therefore promotes solubility at higher temperatures, and, in equilibrium with a second phase of lower entropy, the solubility limit of a solid solution should increase with temperature. This is typically observed, but exceptions are noteworthy, including unexplained cases where solid solubility decreases over a range of temperature, termed ''retrograde'' solubility. Experimental and theoretical investigations have shown that differences in vibrational entropy play an important role in the relative thermodynamic stabilities of solid phases [1][2][3][4][5]. There is now a widespread interest in better understanding the effects of vibrational entropy on phase diagrams, an active topic of ab initio investigations. Here we show, to our knowledge for the first time, a negative entropy of mixing at rather low solute concentrations, caused by the entropy of atomic vibrations. The thermal stability of structurally ordered states and disordered states is thereby reversed.Although the solubility of Ni in the body-centered cubic (bcc) V-rich phase is qualitatively consistent with the entropy of Eq. (1), the elements below Ni in the periodic table, Pd and especially Pt, have similar phase diagrams but show a much weaker temperature dependence of solubility in bcc V [6]. Owing to its incoherent neutron cross section and cubic crystal structure, vanadium is the ideal element for measuring a phonon densityof-states (DOS) by inelastic neutron scattering [7], as are V-rich bcc solid solutions. From the phonon DOS the vibrational entropy and other phonon thermodynamic functions can be obtained, at least at low temperatures. Previous studies of resonance modes of heavy solutes in vanadium suggest important effects on phonon thermodynamics [8][9][10][11].Alloys were prepared by arc melting under a highpurity ar...

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“…Similar effects have been seen by other investigators (7,8). In such eases, the frequency of the largest peak was recorded.…”

Section: Measurement Of the Sound Velocitiessupporting

confidence: 88%

Elastic properties of magnesium silicide

Whitten

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Elastic Constants of Single Crystals of the bcc Transition Elements V, Nb, and Ta

Cited by 218 publications

References 18 publications

The Adhesive Properties of Coherent and Semicoherent NiAl/V Interfaces Within the Peierls-Nabarro Model

The Adhesive Properties of Coherent and Semicoherent NiAl/V Interfaces Within the Peierls-Nabarro Model

Negative Entropy of Mixing for Vanadium-Platinum Solutions

Elastic properties of magnesium silicide

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