Developing MAX phase coatings for nuclear fusion (materials strand project)

Supervisor/s – Dr Phillip Frankel, Dr Rob Harrison & Prof Sarah Haigh (University of Manchester).

Background: MAX phases are a range of layered structures which have the general formula: Mn+1AXn, where n = 1 to 4, M is an early transition metal, A is an A-group (mostly IIIA and IVA) element and X is either carbon and/or nitrogen. This class of materials possesses an extensive chemical and structural diversity including in an intriguing combination of high thermal stability, machinability, corrosion resistance and irradiation-related physical properties, depending on the composition and structural configuration [1,2,3]. The diversity of MAX phase compositions lends itself to the goal of synthesising designer materials optimised for fusion applications. Indeed, the discovery and characterisation of low activation, radiation-hard MAX phases with promising mechanical properties would represent an important step in developing suitable plasma facing component armour for future fusion energy devices.

Recently, new MAX phase ceramics in the (Ta,Ti)3(Al,Si)C2 system were designed, synthesised and characterised using ‘low activation’ elements where possible, for potential use in future nuclear fusion applications [4]. Thermal analysis and proton irradiation trials of (Ta,Ti)3AlC2 phases produced promising results in relation to the materials’ expected response to fusion-relevant environments.

Project: This project will build on these encouraging results to look at the effect of replacing Al with increasing amounts of Si and/or Ga (both elements with lower expected activation than Al in a fusion environment). Initial successful proton irradiations of various (Ta,Ti)3(Al,Si)C2 phases have been performed and the first step in this project will be characterisation of these irradiated materials which is expected to generate the successful student a publication in a relatively short time. Additionally, the student will work with Asst. Prof. Maxim Sokol at TAU in Israel to perform synthesis, characterisation and irradiation testing of the (Ta,Ti)3GaC2 MAX phase materials as this would represent the discovery of an entirely new, low activation, MAX phase. The work will be complemented by physical property measurements to correlate chemical and structural data with the materials’ mechanical properties.

The student will be trained in a suite of state-of-the-art materials characterisation techniques at Manchester including X-ray diffraction, high-resolution transmission and scanning electron microscopy and various mechanical property measurement tools. They will have opportunities to get involved in materials synthesis and to perform irradiations at the University of Manchester’s Dalton Cumbrian Facility, and/or the MIAMI in situ ion irradiation facility in Huddersfield, in order to investigate the response of MAX phases to simulated nuclear fusion environments. The results of these experiments, along with the optimisation of bulk material attributes such as composition, phase purity and microstructure, will then guide the development of radiation-hard MAX phase coatings for future nuclear fusion applications.

Image above: Structural characterisation of a new composition of MAX phase (Ta,Ti)3AlC2. (a, b) scanning electron microscopy images of the material, (c) atomic resolution scanning transmission electron microscopy showing the atomic layer structure corresponding to the schematic shown far left. Scale bars (a-c) are 25 µm, 5 µm and 0.5 nm.

[1] M.W. Barsoum & M. Radovic, Annu. Rev. Mater. Res., 2011, 41, 195–227, https://doi.org/10.1146/annurev-matsci-062910-100448
[2] G. M. Song et al. Scr. Mater., 2008, 58, 13–16, https://doi.org/10.1016/j.scriptamat.2007.09.006
[3] M. W. Barsoum & T. El-Raghy, J. Am. Ceram. Soc., 1996, 79, 1953–1956, https://doi.org/10.1111/j.1151-2916.1996.tb08018.x
[4] Rigby et al. RSC Adv., 2021,11, 3110-3114, https://doi.org/10.1039/D0RA09761F

The project will be mainly based in Manchester, but there is the opportunity for travel to perform irradiation experiments at the in situ microscopy ion irradiation facility in Huddersfield as well as at Dalton Cumbria Facility. Additionally students are encouraged to attend national/international conferences and to engage in collaborations with other groups (nationally and internationally).

This project is offered by The University of Manchester. For further information please contact: philipp.frankel@manchester.ac.uk, Sarah.haigh@manchester.ac.uk, r.w.harrison@manchester.ac.uk

This project may be compatible with part time study, please contact the project supervisors if you are interested in exploring this.