Experimental and Theoretical Understanding of Rhenium Precipitation in Tungsten for Nuclear Fusion Applications
Nuclear fusion promises unlimited supplies of low-carbon energy but major technological challenges must be overcome before this becomes a reality. Many of these are to do with the materials which must survive in the extreme environment of a reactor including tungsten which is destined to be used in plasma-facing components. Under such conditions, rhenium is formed in tungsten via transmutation reactions due to neutron irradiation leading to the formation of tungsten-rhenium precipitates with detrimental consequences for the material. This project will combine experiments and computer modelling to better understand this phenomenon and thus help develop fusion as a promising sustainable energy source.
The Microscopes and Ion Accelerators for Materials Investigations (MIAMI) facility at the University of Huddersfield offers the opportunity to simulate the radiation damage and high temperatures experienced by materials in a nuclear reactor whilst observing their microstructure directly on the nanoscale. This is achieved using ion beams which allow atomic displacements and the introduction of gases akin to those induced by neutrons to be achieved without incurring the risks and challenges of radioactivity. In a similar way using computer modelling of nuclear materials, a toolkit of techniques has been used to model microstructural features and explore their behaviour under irradiation using classical molecular dynamics by the Computational Materials and Minerals Group at Huddersfield. This allows even shorter timescales and smaller length scales to be explored and thus complement the capabilities of experiments performed using the MIAMI facility.
Rhenium (Re) phases have been observed to nucleated in tungsten-rhenium (WRe) alloys under irradiation below the solubility limit of Re where normally it might be expected that Re would remain in solution. Research using MIAMI has already successfully recreated the nuclear reactor conditions which give rise to this  and complementary modelling techniques developed at Huddersfield  are ideal to simulate what happens in the atomic collision cascades and at the boundaries of precipitates –both of which are thought to be key to this fascinating phenomenon.
This project will see the successful candidate first undertake training and perform experiments using the MIAMI-2 system to reproduce and extend the work already done in this area at Huddersfield to explore how WRe alloys behave as functions of temperature, composition and ion beam parameters. The conditions explored and the microstructures identified in the experimental work will then be modelled using classical computational techniques, including molecular dynamics simulations to capture the mechanisms driving the radiation damage processes. This complementary work will provide a deeper understanding of the experimental results on an atomic scale taking advantage of the world-class capabilities developed at Huddersfield in this multi-disciplinary project.
Candidates should have a undergraduate (or higher) degree in engineering, the physical sciences, materials science or a related field with a good materials background. Prior knowledge of computational techniques would be advantageous but is not required.
This PhD position is EPSRC funded and is only available to UK permanent residents. Stipend of £15,245 per annum, incrementing each year.
Funds are also available for travel to national and international conferences/workshops to present work and meet other researchers from around the world.
 RW Harrison, et al. Intermetallic Re phases formed in ion irradiated WRe alloy Journal of Nuclear Materials 514 (2019) p123
 AR Symington, et al. Defect segregation facilitates oxygen transport at fluorite UO2 grain boundaries Philos. Trans. Royal Soc. A 377 (2019) p16