On the recently proposed martensitic-like structural transformation in V, Nb, and Ta

TL;DR

This paper critically examines recent claims of a martensitic transformation in Nb, Ta, and V, finding the effects too small to confirm such a transformation and proposing an alternative explanation involving residual hydrogen precipitation.

Contribution

The study challenges previous claims of martensitic transformation in these metals by analyzing anelastic spectra and suggesting residual hydrogen as a more plausible cause for observed anomalies.

Findings

Effects of the proposed transformation are negligible in spectra

Anomalies likely caused by residual hydrogen precipitation

No evidence supporting the martensitic transformation hypothesis

Abstract

A recent announcement [Phys. Rev. Lett. 107, 075503, (2011)], after anomalies in the thermal expansion, of a previously unknown martensitic transformation in pure Nb, Ta and V is discussed in the light of anelastic measurements on Nb samples with comparable purities. It results that the effects of the alleged transformation on the anelastic spectra would be at least three orders of magnitude smaller than in typical martensitic transformations. A possible alternative explanation for the observed anomalies is proposed in terms of precipitation of unnoticed residual H.