Anisotropic elastic and thermodynamic properties of the HCP-Titanium and the FCC-Titanium structure under different pressures

Publikationen: Beitrag in FachzeitschriftArtikelForschung(peer-reviewed)

Autoren

  • P. D. Hao
  • P. Chen
  • L. Deng
  • F. X. Li
  • J. H. Yi
  • Daniel Şopu
  • J. M. Tao
  • R. Bao

Organisationseinheiten

Externe Organisationseinheiten

  • Kunming University of Science and Technology
  • Erich Schmid Institute of Materials Science of the Austrian Academy of Sciences, Leoben
  • Technische Universität Darmstadt

Abstract

Stress induced phase transformation from hexagonal close-packed titanium (HCP-Ti) to face-centered cubic titanium (FCC-Ti) is believed to be a reason for the pronounced work hardening of carbon nanotube-reinforced titanium (CNT/Ti) composites prepared by high-pressure torsion (HPT). Here, the correlation between the phase transformation from the HCP-Ti to the FCC-Ti structure in Ti and the improved mechanical properties of CNT/Ti composite is revealed by investigating the structural transformation mechanism, the stability, electronic properties, anisotropic elasticity and thermodynamics of the FCC-Ti and HCP-Ti crystals under pressure of 0-15GPa by means of first-principles calculations and comparing with the experimental findings. The results show that the formation enthalpies δHTi, the bulk modulus B, the shear modulus G and the Young's modulus E of the FCC-Ti and HCP-Ti structures gradually increase with increasing pressure, and the hybridization between the electronic orbitals of the atoms becomes stronger. The Young's modulus of the cubic FCC-Ti structure shows strong anisotropy along the [0 1 0] and [1 10] directions, while the HCP-Ti structure exhibits an obvious anisotropy of E in the (1 0 0) crystal plane. The thermodynamic stability of the HCP-Ti and FCC-Ti structures decreases under high pressure. The different relative stability of the two structures results in a high propensity of structural transformation from the HCP-Ti to the FCC-Ti structure. A large number of FCC-Ti structures are prepared, which can effectively improve the mechanical properties of CNT/Ti composites. Our results may help to better understand the phase transition from HCP-Ti to FCC-Ti under high pressure, and may reveal the structure-property relationship of CNT/Ti composites.

Details

OriginalspracheEnglisch
Seiten (von - bis)3488-3501
Seitenumfang14
FachzeitschriftJournal of Materials Research and Technology
Jahrgang9.2020
Ausgabenummer3
DOIs
StatusElektronische Veröffentlichung vor Drucklegung. - 22 Feb 2020