PhD Student Chris Moore Publishes New HEA Paper

Chris’ High Entropy Alloy Research

Christopher Moore, a 2nd year PhD student with the Nuclear Futures Institute has published a paper titled “Hydrogen accommodation in the TiZrNbHfTa high entropy alloy”.

High entropy alloys (HEAs) and their hydrides are a new type of material and this paper works to provide a better understanding of how these high entropy alloy systems behave at the atomic level.

Using density functional theory to model the effect of vacancies on interstitial positions, the phase transformations that occur at high hydrogen concentration and the hydride decomposition temperature range lead to the work being published in Acta Materialia, a high impact scientific journal.

Hydrogen Storage in HEAs

Hydrogen storage materials are highly sought after and materials such as high entropy hydrides which allow for a release of hydrogen over a range of temperatures, could offer significant benefits in terms of efficiency and safety. With this in mind, understanding ways in which we can predict the hydrogen release for given compositions will allow us to determine favourable systems before they are even synthesised.

A graph to show hydrogen interstitials distribution in a high entropy alloy
The decomposition temperature range of the high entropy alloy hydride and the effect on dissolution temperatures for interstitials “trapped” by adjacent vacancies

The trend observed in the figure above is consistent with a release of hydrogen from the structure over a temperature range compared to the single release temperature expected in a standard alloy or metal. This, along with the other interesting properties that HEAs are known to possess, indicates the potential for these materials in a range of applications and environments.

Applications of High Entropy Alloy Hydride Systems

One potential application of these high entropy alloy hydride systems is in fusion technology, as a radiation shielding material, due to their proposed resistance to radiation damage and their potential capacity to moderate and reduce neutron radiation damage to critical components. As a result, this work was completed with the support of the Key Essential Skills Scholarship program, part of the European development fund, and in partnership with Tokamak Energy, a leading private company focused on the production of commercially viable fusion reactor by 2030.

This paper was supported by Tokamak Energy.

Read Chris’ paper as an open access article here.