Pressure derivatives of the elastic moduli of BCC Ti-V-Cr, Nb-Mo and Ta-W alloys

Katahara, Keith; Manghnani, Murli H.; Fisher, E.S.

doi:10.1088/0305-4608/9/5/006

Cited by 211 publications

(96 citation statements)

References 42 publications

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“…A sample of these results for Ta is displayed in Fig. 6 and compared with available experimental data [23][24][25]. In this case, anharmonic effects are found to be small and the observed temperature dependence of the elastic moduli at ambient-pressure [23] is well described by both our quasi-harmonic and Monte Carlo methods.…”

Section: B Atomistically-informed Dd Simulations Of Plasticitymentioning

confidence: 70%

Robust quantum-based interatomic potentials for multiscale modeling in transition metals

et al. 2006

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First-principles generalized pseudopotential theory (GPT) provides a fundamental basis for transferable multi-ion interatomic potentials in transition metals and alloys within density-functional quantum mechanics. In the central bcc metals, where multi-ion angular forces are important to materials properties, simplified model GPT or MGPT potentials have been developed based on canonical d bands to allow analytic forms and large-scale atomistic simulations. Robust, advanced-generation MGPT potentials have now been obtained for Ta and Mo and successfully applied to a wide range of structural, thermodynamic, defect and mechanical properties at both ambient and extreme conditions. Selected applications to multiscale modeling discussed here include dislocation core structure and mobility, atomistically informed dislocation dynamics simulations of plasticity, and thermoelasticity and high-pressure strength modeling. Recent algorithm improvements have provided a more general matrix representation of MGPT beyond canonical bands, allowing improved accuracy and extension to f-electron actinide metals, an order of magnitude increase in computational speed for dynamic simulations, and the development of temperature-dependent potentials.

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Section: B Atomistically-informed Dd Simulations Of Plasticitymentioning

confidence: 70%

Robust quantum-based interatomic potentials for multiscale modeling in transition metals

et al. 2006

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“…28 The elasticity data at high pressure were derived from a third order finite strain equation. 29,30 It may be noted that the use of Eq.…”

Section: Resultsmentioning

confidence: 99%

Strength of polycrystalline niobium from high-pressure x-ray diffraction data: A comparison of results from line-width and line-shift analyses

Singh

Liermann

2015

Journal of Applied Physics

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High purity polycrystalline niobium was compressed in a diamond anvil cell (DAC) without any pressure transmitting medium and the pressure was increased in steps of ∼5 GPa to the highest pressure of ∼40 GPa. The diffraction pattern was recorded after each pressure increment using angle-dispersive mode with the conventional diffraction geometry, wherein the primary x-ray beam is parallel to the load axis of the DAC. The strength of niobium as function of pressure was determined using the line-width and line-shift analyses. Both eY and 2eY, where Y is the aggregate Young's modulus and e is the strain determined from the line-width analysis, have been used as the measure of strength in earlier studies. In this study, it is eY that agrees with the strength determined from the line-shift analysis of the radial diffraction data as well as the data from the conventional diffraction geometry. These results have been discussed and compared with a similar observation made earlier on strength of diamond. This study highlights the ambiguity that presently exists in choosing eY or 2eY as a measure of strength while attempting to estimate the strength from the diffraction line width analysis.

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“…[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%

“…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%

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

et al. 2008

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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.

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Pressure derivatives of the elastic moduli of BCC Ti-V-Cr, Nb-Mo and Ta-W alloys

Cited by 211 publications

References 42 publications

Robust quantum-based interatomic potentials for multiscale modeling in transition metals

Robust quantum-based interatomic potentials for multiscale modeling in transition metals

Strength of polycrystalline niobium from high-pressure x-ray diffraction data: A comparison of results from line-width and line-shift analyses

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

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