Lattice Dynamics of bcc Zirconium

Abstract

We have studied the lattice dynamics of bcc Zr at 1400 K. We find that (a) the [111] longitudinal branch plunges rapidly to low frequencies in the vicinity of $q=\frac{2}{3}\mathrm{}\left[111\right]\mathrm{}$ indicating a nautral inclination for this metal to undergo a structural transformation to the $\omega$ phase, (b) the [110] longitudinal branch is anomalous at the zone boundary, and (c) the condition of elastic isotropy is satisfied to within experimental error. Temperature-dependent elastic peaks were observed in the vicinity of the reciprocal lattice points of the $\omega$ phase.