Extreme metallurgy: melting of transition metals in the laser-heated diamond anvil cell - Oliver Lord

Oliver Lord -  Bristol University

Jeudi 2 octobre 2014 à 10 h

IMPMC, Université P. et M. Curie, 4, Place Jussieu, 75005 Paris

Salle de conférence, 4^e étage, Tour 22-23, Salle 1

Abstract

For many years, there has been controversy regarding the phase diagrams of many of the transition metals. On the one hand, /ab initio/ and classical molecular dynamics and shockwave experiments tend to yield hotter, steeper melting curves for many of these materials, whereas the available static DAC data yield cooler, almost flat melting curves [1]. This has led to many exotic suggestions designed to marry the two, such as the effect of shortrange order in the liquid phase, vacancy formation, and the formation of shear induced '1-D' metallic glass. However, new results on Ni [2], Fe [3] and Ta [4], as well as preliminary data on Cu, Mo, and V suggest that the entire controversy may be an experimental artifact.
I will discuss the techniques we use to determine the melting curves of transition metals and discuss our new results in light of current theories on the phase diagrams of the
transition metals.

[1] Errandonea, /Physica B/ (2005)
[2] Lord et al., /Earth & Planetary Science Letters/ (in review)
[3] Anzellini et al., /Science/ (2013)
[4] Dewaele et al., /Physical Review Letters/ (2010)

Contact : Christian Brouder (Christian.Brouder @ impmc.upmc.fr)