Evaluation of the structure and properties for the high-temperature phase of zirconium from the atomistic simulations

• Published in: Computational materials science Vol. 152; pp. 51 - 59
• Main Authors: Smirnova, D.E., Starikov, S.V., Gordeev, I.S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2018
• Subjects: Diffusion; Heat capacity; Interatomic potentials; Molecular dynamics; Niobium; Phase transitions; Zirconium; Zirconium alloys; Zirconium; Molecular dynamics; Heat capacity; Diffusion; Interatomic potentials; Phase transitions; Niobium; Zirconium alloys
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2018.05.025

[Display omitted] •We applied molecular dynamics for the study of phase transitions in Zr.•We paid special attention to the unstable behavior of beta-Zr at low temperatures.•We assume a local non-cubic symmetry in beta-Zr explaining fast self-diffusion.•We report results of the deformation tests made for the models of beta-Zr-Nb alloys. We study peculiarities of phase transitions in zirconium and properties of the high-temperature β-Zr phase. To get a more detailed understanding of the structure and thermodynamic characteristics of zirconium, we perform atomistic simulations with two different interatomic potentials. Both potentials demonstrate an unstable behavior of β-Zr phase at low temperatures but explain this phenomenon by substantially different reasons. For one of the potentials, the mechanical instability takes place, and for the other potential the instability of β-Zr is purely dynamic. Review of the available experimental data shows that it is more correct to describe β-Zr through the low-temperature dynamic instability. The structure peculiarity discussed for β-Zr leads to a local non-cubic symmetry of this phase and low formation energy of the self-interstitial atoms. The latter leads to fast atomic self-diffusion that is consistent with existing data. We also perform deformation tests for the atomistic models of β-Zr-Nb alloys taking into account the studied details of α-β transition.