Understanding Irradiation Stability of Ti-CON Precipitates in Vanadium Alloys

Supervision and International Collaborations: You will be based at the University of Birmingham and will be co-supervised by the industrial partner Tokamak Energy Ltd. (https://tokamakenergy.com/). This project will involve multi-national collaborators, and so you will have a unique opportunity to work with renowned industrial experts and with world-recognized institutes such as Oak Ridge National Lab, University of Tennessee, University of Michigan in the US, and University of Paris-Saclay in France. You will work in a diverse, inclusive, friendly and collaborative environment that nurtures excellence and innovation. You will be given proper mentorship to develop transferable skills so that you have a successful post-PhD career.

Background:

Successful fusion energy demonstration depends upon availability of high-performance materials that can withstand the harsh fusion operating conditions. These include a simultaneous presence of elevated temperatures, high neutron doses, corrosive liquids and thermo-mechanical stresses including very high magnetic fields. For fusion first-wall/blanket concepts utilizing liquid lithium, vanadium (V) alloys based on V-Cr-Ti ternary system are regarded worldwide as the leading candidates. This is because V alloys have excellent compatibility with liquid lithium. Further, V alloys have other desirable properties such as non-ferromagnetic nature, high thermal conductivity, low thermal expansion coefficient, low activation, and good high-temperature creep strength up to 700-750 °C. Advanced V alloy variants derive their high temperature creep strength by titanium oxy-carbonitride (Ti-CON) nanoprecipitation under thermal ageing. The susceptibility of thermally formed Ti-CON particles to irradiation is currently unknown – which is essential to be quantified to predict V alloy’s performance. Further, Ti-CON phase may also form under irradiation, well below the temperatures needed for thermal ageing. While Ti-CON produced by thermal ageing is beneficial to high-temperature properties, Ti-CON due to irradiation is deleterious because it is attributed to severe irradiation embrittlement. A key missing gap is understanding of the mechanisms that control Ti-CON precipitation in V alloys under combined presence of high temperature and fusion-relevant irradiation conditions, which is what this study aims to establish.

The Project:

This study will evaluate the Ti-CON nanoprecipitation phenomenon in V-Cr-Ti alloys using irradiation experiments over a wide range of temperatures and advanced microstructure characterization. Two specific questions to be studied are:

(i) Understanding the mechanisms of radiation-induced precipitation (RIP) of Ti-CON in V-Cr-Ti alloys.

(ii) Understanding the susceptibility of pre-existing Ti-CON nanoprecipitates in V-Cr-Ti alloys to irradiation-induced degradation, such as ballistic dissolution.

The specific material to be studied is V-4%Cr-4%Ti, a composition previously down-selected by the U.S. Fusion Materials programme.

Who we are looking for:

A first or upper-second-class degree in an appropriate discipline: materials science and engineering, nuclear/chemical/mechanical/aerospace engineering, physics, plasma-physics, condensed-matter physics. No prior experience is mandatory. Some exposure to microstructural characterisation, fission/fusion basics would be advantageous.

A self-motivated, inquisitive, genuine and driven individual.

Contact:

Please contact Prof. Arunodaya (Arun) Bhattacharya – a.bhattacharya.1@bham.ac.uk and/or Dr. Samara M. Levine – Samara.Levine@tokamakenergy.com to informally discuss your motivation. Include the following: CV and transcripts.