PhD Studentship: Evaluation of weld deposited novel iron based hard facings

Nuclear power plants are complex engineering structures with a multitude of different components required to make them operate. One area that rarely hits the headlines, but it fundamental to the operation of the plant is tribological components, i.e. parts that are in contact and in relative motion to each other resulting in friction and wear. In a nuclear power plant, these components operate in a particularly aggressive environment. Unlike, for example, an internal combustion engine where lubrication is provided by highly optimised oils, in a nuclear power plant the lubricant is just superheated water. The water provides limited lubrication and indeed makes matters worse as it is corrosive. Traditionally, there has only been one material that can survive this highly hostile environment: cobalt based alloys called Stellite hard facing alloys. However, there is a big problem with these alloys. The radiation from the reactor results in the formation of cobalt-60 radioisotope when cobalt atoms are exposed to a neutron flux; cobalt-60 is one of the principle root causes of the dose received by site workers and also contributes to radioactive waste.

The obvious answer to this problem is to remove the cobalt from the hard facing. Thus, the next generation of nuclear power plants will require new alloys to replace the traditionally used cobalt-based hard facings. To meet the requirements of the new plants, the new alloys must be capable of being available in a number of manufactured forms and have wear characteristics equivalent to the cobalt base alloys.

In this project will explore some exciting new opportunities in new iron-based hard facing alloys. These will be manufactured through a new process route, namely, a new powder-based weld deposition technique. The new hard facings will be extensively characterised through the latest electron microscopy techniques. The wear behaviour will be investigated using the extensive suite of test instruments at Sheffield University. This will be augmented by tests at a special autoclave facility at Rolls-Royce.

The outputs of the project will be to provide microstructural understanding of the alloys during the weld deposition process and then relate the weld microstructures to their tribological performance and provide detailed mechanistic understanding of the wear mechanisms involved. This will provide a major step forward in bringing these alloys into service for the next generation nuclear power plants.

Funding Notes

The project will be run as an iCASE studentship sponsored by Rolls-Royce. Tuition Fees will be paid at UK/EU rates for 2017/2018. A maintenance stipend of £17,400 per annum will also be paid. Applications from International students CANNOT be accepted for this project due to the criteria set out by the funding body.

To be eligible, you must be a U.K. citizen who has been resident in the UK for at least 3 years prior to starting the degree. Under exceptional cases, EU applicants may be considered.

References

Students with a First or Second High Upper Class Degree in Material Science and Engineering/ Chemistry / Physics or Mechanical Engineering or a closely related subject are invited to apply. Candidates should have a background in experimental research.
Demonstrated ability of independent academic research and contribution to scientific publications will constitute an added advantage.