First-principles phase transition and equation of state of titanium

Hao, Yanjun; Zhang, L.; Chen, Xiangrong; Li, Yinghua; He, Hongliang

doi:10.1016/j.ssc.2008.02.012

Cited by 28 publications

(20 citation statements)

References 27 publications

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“…These transition pressures are a little lower than those of the results of Hao et al 12 We also found that the ␦ phase is stable between 104-144 GPa using BM3 EOS, as shown is Fig. 6͑b͒, which is very close to the results of Kutepov et al 12 However, our direct VASP calculations show that the ␦ phase is not stable in the whole pressure region and becomes bcc when relaxed at high pressures. Thus, one has to be very careful in using any EOS fitting in predicting the phase transition sequence of Ti.…”

Section: Resultssupporting

confidence: 89%

“…5, we can also obtain a metastable phase transition ␣ → ␤ at 63 GPa, which is comparable to the extrapolated value 50 GPa from the experimentally determined phase diagram. 25 Our 0 K phase transition sequence is different from the results by Kutepov and Kutepova 15 and Hao et al 12 Kutepov and Kutepova 15 predicted that the ␦ phase is stable between 106-136 GPa while Hao et al 12 showed that the ␦ phase is stable between 134.9-160.8 GPa using the Vinet EOS fitting, although Kutepov and Kutepova 15 did not mention how they calculated the pressure. To explore the origin of the differences, we used Vinet EOS to fit our calculated E-V data of all the phases using data in the whole pressure range.…”

Section: Resultscontrasting

confidence: 72%

“…The phase has the lowest energy at its equilibrium volume, consistent with most theoretical predictions. 9,12,15 Our calculations show that there is a small interval of stability for ␥, while ␦ is not stable in the entire volume region. This result is in agreement with the work of Verma et al 9 but contrary to the calculations of Kutepov and Kutepova.…”

Section: Resultsmentioning

confidence: 71%

“…However, EOS fitting can be a significant source of error when the free-energy difference between phases is small. This could be a reason why the ␦ phase is stable in some predictions 12,15 while unstable in others 9 since ␤, ␥, and ␦ phases have very similar free energies in the phase transition regions.…”

Section: Introductionmentioning

confidence: 99%

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Density-functional study of the pressure-induced phase transitions in Ti at zero Kelvin

et al. 2009

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The pressure-induced stable and metastable phase transitions of Ti at 0 K were studied by first-principles density-functional calculations. With the pressure from the equation of state fitting or extracted directly from first-principles calculations, we predicted that the 0 K phase transition sequence of Ti is ␣ → → ␥ → ␤, which is different from the theoretic predictions in the literature. We also found that the ␦ phase is not stable under hydrostatic compression. The obtained stable ͑␣ → → ␥ → ␤͒ and metastable ͑␣ → ␤͒ phase transition pressures are in a good agreement with the experimental results. We found that the equation of state based on different fitting schemes can introduce significant errors in predicting the transition sequence of Ti. Our calculations also show that only under −8.0 GPa, the ␤ phase exhibits magnetism. However, it is energetically not stable with respect to the ␣ and phases at low pressures.

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Section: Resultssupporting

confidence: 89%

Section: Resultscontrasting

confidence: 72%

Section: Resultsmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

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Density-functional study of the pressure-induced phase transitions in Ti at zero Kelvin

et al. 2009

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“…In our previous work, 18 we only obtained the phase transition and EOS of ␣and -Ti by using the Debye model. But in the present work, we describe a systematical investigation of the high pressure behaviors of Ti, including accurate structural and elastic properties, the phase diagram, and thermal EOS.…”

Section: Introductionmentioning

confidence: 99%

Theoretical investigation of the high pressure structure, lattice dynamics, phase transition, and thermal equation of state of titanium metal

Zhao-Yi

Zhang

et al. 2010

Journal of Applied Physics

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Resonant frequency analysis of Timoshenko nanowires with surface stress for different boundary conditions J. Appl. Phys. 112, 074322 (2012) Giant domain wall response of highly twinned ferroelastic materials Appl. Phys. Lett. 101, 141913 (2012) Electromechanical instabilities of thermoplastics: Theory and in situ observation Appl. Phys. Lett. 101, 141911 (2012) Mechanical properties and local mobility of atactic-polystyrene films under constant-shear deformation J. Chem. Phys. 137, 124902 (2012) Effect of macroscopic relaxation on residual stress analysis by diffraction methodsWe report a detailed first-principles calculation to investigate the structures, elastic constants, and phase transition of Ti. The axial ratios of both ␣-Ti and -Ti are nearly constant under hydrostatic compression, which confirms the latest experimental results. From the high pressure elastic constants, we find that the ␣-Ti is unstable when the applied pressures are larger than 24.2 GPa, but the -Ti is mechanically stable at all range of calculated pressure. The calculated phonon dispersion curves agree well with experiments. Under compression, we captured a large softening around ⌫ point of ␣-Ti. When the pressure is raised to 35.9 GPa, the frequencies around the ⌫ point along ⌫-M-K and ⌫-A in transverse acoustical branches become imaginary, indicating a structural instability. Within quasiharmonic approximation, we obtained the full phase diagram and accurate thermal equations of state of Ti. The phase transition -Ti→ ␣-Ti→ ␤-Ti at zero pressure occurs at 146 K and 1143 K, respectively. The predicted triple point is at 9.78 GPa, 931 K, which is close to the experimental data. Our thermal equations of state confirm the available experimental results and are extended to a wider pressure and temperature range.

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First Principles Investigation of Cold Curves of Metals

Eidelstein

Barzilai²,

Curtarolo

et al. 2020

Israel Journal of Chemistry

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The rapid development of better high pressure experimental techniques combined with efficient and accurate density functional calculations of the structural properties of materials provide a new avenue to promote the study of materials at high pressures, which is currently based mostly on simple phenomenological modelling. The progress of experimental results into higher-pressure regimes represents a challenge to the phenomenological approaches, which can be addressed by carefully considered ab initio calculations. We present cold curves of several elements, calculated using different approximations of DFT and compare them with available experimental data. The comparison shows good agreement both in simple single phase and complex multi-phase cases. It suggests that DFT may be used to extrapolate high pressure behaviour of materials beyond the currently possible pressure range, with a robust estimate of the accuracy of the extrapolation based on various DFT implementations.

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First-principles phase transition and equation of state of titanium

Cited by 28 publications

References 27 publications

Density-functional study of the pressure-induced phase transitions in Ti at zero Kelvin

Density-functional study of the pressure-induced phase transitions in Ti at zero Kelvin

Theoretical investigation of the high pressure structure, lattice dynamics, phase transition, and thermal equation of state of titanium metal

First Principles Investigation of Cold Curves of Metals

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