skip to main content

DOE PAGESDOE PAGES

This content will become publicly available on January 28, 2019

Title: First-principles study of the α- ω phase transformation in Ti and Zr coupled to slip modes

Here, we present first-principles density functional theory calculations to study the α-ω phase transformation in Ti and Zr and its coupling to slip modes of the two phases. We first investigate the relative energetics of all possible slip systems in the α and ω phases to predict the dominant slip system that is activated during a plastic deformation under an arbitrary load. Using this and the crystallographic orientation relationships between α and ω phases, we construct low energy α/ω interfaces and study the energetics of the slip system at the interface between α and ω to compare to the slip systems in the bulk phases. We find that for a particular crystallographic orientation relationship, where (basal) α ∥ (prismatic–II) ω, and [a] α ∥ [c] ω , the slip at the interface is preferred compared to its bulk counterparts. This implies that the plastically deformed α/ω phase with this orientation relationship prefers to retain the interface (or coexisting phases) than transforming back to the pure phase after unloading. This is consistent with the observation that the ω-phase is retained in samples loaded in flyer plate experiments or under high-pressure torsion. Furthermore, calculation of the energy barrier for α to ωmore » phase transformation as a function of glide at the α/ω interface shows significant coupling between the α-ω phase transformation and slip modes in Ti and Zr.« less
Authors:
 [1] ;  [1] ;  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
LA-UR-17-28452
Journal ID: ISSN 0021-8979
Grant/Contract Number:
AC52-06NA25396; ASC
Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 123; Journal Issue: 4; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Material Science
OSTI Identifier:
1477717
Alternate Identifier(s):
OSTI ID: 1418727

Kumar, Anil, Bronkhorst, Curt A., and Lookman, Turab. First-principles study of the α-ω phase transformation in Ti and Zr coupled to slip modes. United States: N. p., Web. doi:10.1063/1.5007074.
Kumar, Anil, Bronkhorst, Curt A., & Lookman, Turab. First-principles study of the α-ω phase transformation in Ti and Zr coupled to slip modes. United States. doi:10.1063/1.5007074.
Kumar, Anil, Bronkhorst, Curt A., and Lookman, Turab. 2018. "First-principles study of the α-ω phase transformation in Ti and Zr coupled to slip modes". United States. doi:10.1063/1.5007074.
@article{osti_1477717,
title = {First-principles study of the α-ω phase transformation in Ti and Zr coupled to slip modes},
author = {Kumar, Anil and Bronkhorst, Curt A. and Lookman, Turab},
abstractNote = {Here, we present first-principles density functional theory calculations to study the α-ω phase transformation in Ti and Zr and its coupling to slip modes of the two phases. We first investigate the relative energetics of all possible slip systems in the α and ω phases to predict the dominant slip system that is activated during a plastic deformation under an arbitrary load. Using this and the crystallographic orientation relationships between α and ω phases, we construct low energy α/ω interfaces and study the energetics of the slip system at the interface between α and ω to compare to the slip systems in the bulk phases. We find that for a particular crystallographic orientation relationship, where (basal)α ∥ (prismatic–II)ω, and [a]α ∥ [c]ω , the slip at the interface is preferred compared to its bulk counterparts. This implies that the plastically deformed α/ω phase with this orientation relationship prefers to retain the interface (or coexisting phases) than transforming back to the pure phase after unloading. This is consistent with the observation that the ω-phase is retained in samples loaded in flyer plate experiments or under high-pressure torsion. Furthermore, calculation of the energy barrier for α to ω phase transformation as a function of glide at the α/ω interface shows significant coupling between the α-ω phase transformation and slip modes in Ti and Zr.},
doi = {10.1063/1.5007074},
journal = {Journal of Applied Physics},
number = 4,
volume = 123,
place = {United States},
year = {2018},
month = {1}
}

Works referenced in this record:

Generalized Gradient Approximation Made Simple
journal, October 1996
  • Perdew, John P.; Burke, Kieron; Ernzerhof, Matthias
  • Physical Review Letters, Vol. 77, Issue 18, p. 3865-3868
  • DOI: 10.1103/PhysRevLett.77.3865

Projector augmented-wave method
journal, December 1994

From ultrasoft pseudopotentials to the projector augmented-wave method
journal, January 1999

Electron-energy-loss spectra and the structural stability of nickel oxide: An LSDA+U study
journal, January 1998
  • Dudarev, S. L.; Botton, G. A.; Savrasov, S. Y.
  • Physical Review B, Vol. 57, Issue 3, p. 1505-1509
  • DOI: 10.1103/PhysRevB.57.1505

Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set
journal, July 1996

Special points for Brillouin-zone integrations
journal, June 1976
  • Monkhorst, Hendrik J.; Pack, James D.
  • Physical Review B, Vol. 13, Issue 12, p. 5188-5192
  • DOI: 10.1103/PhysRevB.13.5188

Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set
journal, October 1996