Elastic anisotropy, vibrational, and thermodynamic properties of U{sub 2}Ti intermetallic compound with AlB{sub 2}-type structure under high pressure up to 100 GPa

Journal Article · Sat Mar 28 00:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4916334· OSTI ID:22399368

Yang, Jinwen ^[1]; Gao, Tao ^[1]; Liu, Benqiong; Sun, Guangai; Chen, Bo ^[2]

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1. Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China)
2. Key Laboratory of Neutron Physics, Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China)

Structural, elastic anisotropy, dynamical, and thermodynamic properties of U{sub 2}Ti have been studied by employing density functional theory and density functional perturbative theory. The optimized lattice parameters a, c, unit volume V, bulk modulus B, and bond lengths d{sub U-U}, d{sub U-Ti} of U{sub 2}Ti are in favorable agreement with the available experimental data and other theoretical values. The elastic constants under pressure were obtained using “energy-strain” method. The polycrystalline modulus, Poisson's ratio, brittle/ductile characteristics, Debye temperature and the integration of elastic wave velocities over different directions, and hardness under pressure are also evaluated successfully. The anisotropy of the directional bulk modulus and the Young's modulus is systematically predicted for the first time. It turns out that U{sub 2}Ti should be stabilized mechanically up to 100 GPa, this compound just possesses slightly elastic anisotropy at zero pressure; however, the anisotropy becomes more and more significant with the increasing pressure. In particular, the phonon dispersion curves and phonon density of state under pressure are reported for the first time. The Raman and infrared-active phonon modes at Γ point are further assigned. Our results indicate that U{sub 2}Ti is also stable dynamically up to 100 GPa. Additionally, within the calculated phonon density of states, the thermodynamic properties are predicted.

• OSTI ID: 22399368
• Journal Information: Journal of Applied Physics, Vol. 117, Issue 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM BORIDES
ANISOTROPY
BOND LENGTHS
DEBYE TEMPERATURE
DENSITY FUNCTIONAL METHOD
DENSITY OF STATES
HARDNESS
INTERMETALLIC COMPOUNDS
LATTICE PARAMETERS
PHASE DIAGRAMS
PHONONS
POLYCRYSTALS
PRESSURE DEPENDENCE
PRESSURE RANGE GIGA PA
STRAINS
THERMODYNAMIC PROPERTIES
TITANIUM
URANIUM
YOUNG MODULUS