Elastic constants and volume changes associated with two high-pressure rhombohedral phase transformations in vanadium

TL;DR

This study uses ab initio calculations to analyze the elastic properties and volume changes during high-pressure phase transitions in vanadium, revealing minimal volume change and elastic discontinuities.

Contribution

It provides detailed computational insights into the elastic and volume properties of vanadium's high-pressure phases, which were previously characterized experimentally.

Findings

Volume change is no more than 0.15% during phase transitions.

Elastic moduli show minimal discontinuity across transitions.

Results are relevant for dynamic high-pressure experiments.

Abstract

We present results from ab initio calculations of the mechanical properties of the rhombohedral phase (beta) of vanadium metal reported in recent experiments, and other predicted high-pressure phases (gamma and bcc), focusing on properties relevant to dynamic experiments. We find that the volume change associated with these transitions is small: no more than 0.15% (for beta - gamma). Calculations of the single crystal and polycrystal elastic moduli (stress-strain coefficients) reveal a remarkably small discontinuity in the shear modulus and other elastic properties across the phase transitions even at zero temperature where the transitions are first order.