Bcc-superalloys: Engineering Resilience to Extreme Environments

Nuclear fusion, Generation IV fission reactors and aerospace gas turbines are critical to our future energy generation and transportation. Their operation at high temperatures necessitates construction from a variety of advanced materials. In order to withstand these extreme environments materials require high melting points, high temperature strength and environmental resistance, and, for nuclear, irradiation resistance. There are strong environmental and economic incentives to yet further increase the temperature capability of the materials used, in order to improve efficiency to reduce fuel use, as well as for improve performance, design life and safety. However, while iterative improvements are being made year on year the temperature gains are becoming ever harder to realise. In this proposal a step change in temperature capability is sought by the realisation of a new class of body-centred-cubic (bcc, an atomic crystal structure) superalloys based on (1) Tungsten, (2) Titanium, and (3) Steel, for the extreme environments of nuclear fusion and gen IV fission reactors as well as aerospace gas turbine engines.

I will create a close network of industrial, national and international academic partners, that will enable translation of these advanced materials from concept through to scale-up. The collaborations will be split across the bcc-superalloys Work Packages: (WP1) Tungsten, bringing in Culham Centre for Fusion Energy (CCFE), and ANSTO Sydney, toward nuclear fusion and Gen IV fission; (WP2) Titanium, brining in TIMET and Rolls Royce, for aero-engines, as well as ETH Zurich for thin film based alloy discovery; (WP3) Steel, bringing in Rolls Royce, for gas/steam turbines, and the Max-Planck-Institut für Eisenforschung (Iron Research, MPIE) Dusseldorf for advanced characterisation and steels expertise.

Bcc superalloys comprise a metal matrix, where the atoms are arranged in a bcc crystal structure, which are reinforced by forming precipitates of high strength ordered-bcc intermetallic compounds (e.g. TiFe or NiAl). This has parallels to the strategy used in current face-centred-cubic (fcc) nickel-based superalloys. However, changing the base metal's crystal structure, and therefore also the reinforcing intermetallic compound, represents a fundamental redesign and necessitates the development of new understanding. The key advantage of using a bcc refractory-metal-, titanium-, or steel- based superalloy is their increased melting point(s), which give the possibility of increased operating temperatures, as well as greatly reduced cost for the case of steels. However, the change in crystal structure requires a fundamentally new design strategy. While the limited investigations into bcc superalloys have indicated that they have attractive strength, and creep resistance, they have been held back by their low ductility. During this fellowship, I will thoroughly investigate multiple ductilisation strategies on bcc-superalloys to advance their technology readiness level (TRL) and so remove the current barrier to their commercialisation.

Investigation of the systems will be undertaken by myself, the 2 Research Fellows (RF), technician, and PhD students allowed for by the programme, as well as staff time from the project partners (CCFE, TIMET, Rolls Royce, ANSTO, ETH Zurich and MPIE). The PhD students will undertake alloy development between: WP1 on Tungsten alloys 50% supported by CCFE, WP2 on Titanium, two students, one 50% by TIMET and a second 50% by Rolls Royce, with a fourth school funded by UoB on WP3 industrially supervised by Rolls Royce. The two 2 RFs and technician would work in alloy development and characterisation alongside these students, but also perform more detailed investigations, with one RF focussed on irradiation damage mechanisms, and the second RF on deformation mechanisms, both using advanced microscopy and micromechanics on which the related students would be progressively trained.

This fellowship seeks significant improvements in the efficiencies of gas and steam turbines used for air transport and energy generation, and performance of nuclear fusion/fission reactors. Improvements in efficiency would reduce fuel consumption and polluting emissions alongside reducing the cost of air transport and energy, providing wide societal benefits. This research is aligned to the long-term research interests of key UK companies CCFE, Rolls-Royce and TIMET for whom it would offer significant competitive advantage, with concomitant creation of high value manufacturing jobs across the whole of the UK economy, rather than just in the south-east.

This research will be disseminated through peer review journal publications and conference presentations and through outreach to UK industry at workshops, IOM3 meetings and company visits. Quarterly meetings with Rolls-Royce and TIMET will ensure the steel/titanium alloys align with engineering and scale up requirements, and the progress of new tungsten alloys discussed with CCFE and EURO-Fusion partners.

Exploitable IP will be patented and licensed jointly with the industrial partners and through University of Birmingham Enterprise. For alloy development IP it is critical to involve industrial partners both at the end application (e.g. Rolls-Royce and CCFE) and primary production (e.g. TIMET). Firstly this is to demonstrate the need, secondly, to ensure that the innovative material can be produced in a practical and cost-competitive manner capable of displacing the existing materials. TIMET and Rolls-Royce have well established routes for the commercialisation of new materials and long-term cooperative agreements with UoB. Onward research grants (e.g. Innovate UK) will also be sought to support this academically, alongside further industry co-funded PhDs, leveraging government funds to deliver impact.

Another impact will be training of new materials engineers, through the promised PhD funding (UoB, CCFE, Rolls-Royce and TIMET) and MSc students. Metallurgists are in great demand from UK job creators (e.g. Firth Rixson, Tata, JLR, BMW-Mini, TIMET, Siemens, EDF, Safran, Hitachi, Airbus, etc, and Rolls-Royce), as well as UK government and infrastructure (rail, BAE systems, MOD, etc). This supply gap has been met by cross-training scientists/engineers from other disciplines and by immigration, which given the UK's recent societal shift there is a need for the UK to internally grow highly qualified engineers.

Throughout the fellowship the research will regularly be disseminated through peer reviewed papers toward high impact journals. The work will also be presented at the major international conferences in the field (TMS, US, Gordon Research Conference in Physical Metallurgy), focussed EU/UK conferences (Beyond Nickel-Based Superalloys, Nuclear Materials and Intermetallics), UK-specific meetings (UK Nuclear Academics meeting) as well as CDT- and programme-grant specific large workshops.

Societal impact will be maximised through outreach targeting four groups:
1) Ages 12-16, encouraging STEM uptake, at local secondary school visits, via UoB and CCFE, and at science festivals, e.g. New Scientist Live.
2) Ages 16-18, encouraging enrolment in science and engineering degrees, utilising the widening participation programme at UoB on underrepresented groups, and engaged audiences at Pint of Science, Café Scientific and university open days.
3) Public of all ages, will be engaged to promote Science & Engineering and nuclear energy. At festivals, events and talks as mentioned, and the BlueDot festival with CCFE, working with the Henry Royce Institute engagement officer based at UoB, and to seek media engagement via the UoB and CCFE press offices and Science Media Centre.
4) Public policy, will be influenced via the annual UK Nuclear Academics Meetings, BEIS and Parliamentary secondments, UK AMR programme and UK GIF representation.