https://doi.org/10.1140/epjb/e2016-70218-0
Regular Article
A first-principle study on the phase transition, electronic structure, and mechanical properties of three-phase ZrTi2 alloy under high pressure*
1 College of Science, Hohai University,
1 Xikang Road,
Nanjing
210098, P.R.
China
2 College of Harbour Coastal and
Offshore Engineering, Hohai University, Nanjing
210098, P.R.
China
3 College of Mechanics and Materials,
Hohai University, 1 Xikang
Road, Nanjing
210098, P.R.
China
a
e-mail: xlyuan@hhu.edu.cn
b
e-mail: mi-anxue@163.com
Received:
10
April
2016
Received in final form:
9
July
2016
Published online:
14
November
2016
We employed density-functional theory (DFT) within the generalized gradient approximation (GGA) to investigate the ZrTi2 alloy, and obtained its structural phase transition, mechanical behavior, Gibbs free energy as a function of pressure, P-V equation of state, electronic and Mulliken population analysis results. The lattice parameters and P-V EOS for α, β and ω phases revealed by our calculations are consistent with other experimental and computational values. The elastic constants obtained suggest that ω-ZrTi2 and α-ZrTi2 are mechanically stable, and that β-ZrTi2 is mechanically unstable at 0 GPa, but becomes more stable with increasing pressure. Our calculated results indicate a phase transition sequence of α → ω → β for ZrTi2. Both the bulk modulus B and shear modulus G increase linearly with increasing pressure for three phases. The G/B values illustrated good ductility of ZrTi2 alloy for three phases, with ω<α<β at 0 GPa. The Mulliken population analysis showed that the increment of d electron occupancy stabilized the β phase. A low value for B '0 is the feature of EOS for ZrTi2 and this softness in the EOS is representative of pressure induced s-d electron transfer.
Key words: Solid State and Materials
Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjb/e2016-70218-0
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2016