Molecular-dynamics computations based on a simple tight-binding interatomic potential fitted to hcp zirconium confirm the Burgers mechanism for the temperature-dependent hcp-bcc phase transition. In our model the transverse ${\mathrm{T}}_1$ [110]-bcc N-point phonon, which is involved in the transition, is unstable in the quasiharmonic approximation but stable at high temperatures. In addition, we calculate the vibrational entropy difference Δ${\mathrm{S}}_{\mathrm{vib}}$ between the two phases. The small value of Δ${\mathrm{S}}_{\mathrm{vib}}$ proves the importance of the electronic contribution to the total ΔS in the case of Zr.

• Received 14 September 1989

DOI:https://doi.org/10.1103/PhysRevLett.63.2244