Phase transition and elastic constants of zirconium from first-principles calculations

Abstract

Using the projector augmented wave (PAW) within the Perdew-Burke-Ernzerhof (PBE) form of the generalized gradient approximation (GGA), we investigate the effect of hydrostatic pressure on the structures of zirconium metal at zero temperature. We obtain the [Formula: see text] transition at around 26.8 GPa, which is in excellent agreement with the experimental values. We also find that the ω phase is most stable at 0 K and 0 GPa. This conclusion is supported by first-principles calculations of Schell et al and Jona et al. The elastic constants of ω-Zr under high pressures are calculated for the first time. We find that the compressional and shear wave velocities increase monotonically with increasing pressure and the results are in good agreement with the available experimental data. The pressure dependences of three anisotropies of elastic waves are also presented.

Computations of Ultrasonic Parameters in Alloys

“…Published theoretical/experimental data on the elastic constants for the chosen alloys are not available for comparison. Comparison for the present values to theoretical/experimental studies of pure metals, as shown in Table 1, demonstrates that results obtained from the present investigation are higher than those of the pure metals as reported by other investigators [24,25]. The obtained values of the SOEC and TOEC are of the same order as previous experimental and theoretical studies of other metallic alloys and metals [19,21,[26][27][28].…”

Density functional study of the phase diagram and thermodynamic properties of Zr

“…By comparing the enthalpies of a-, x-and b-Zr, we found that the stable phase is a-Zr at zero pressure and temperature. The a-Zr transforms to x-Zr and then to b-Zr occurs at 0.98 GPa and 31.6 GPa at zero temperature, which agree with the theoretical results [35][36][37][38]. The transition pressures at high temperature will be discussed subsequently in the P-T phase diagram section.…”

Evidence for the antiferromagnetic ground state of Zr2TiAl: a first-principles study

“…They are widely used in aerospace industry due to their light weight, static strength, stiffness and oxidation resistance. [1,2,3,4,5,6,7] This especially concerns their aluminides, Zr 3 Al and Ti 3 Al, which are important in high temperature applications. [8,9,10,11,12] Titanium rich and zirconium ternary aluminides can be obtained by mixing Zr 3 Al and Ti 3 Al.…”