Modelling environmentally assisted cracking in Ni-based superalloys

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Ni-based superalloys are extensively used in aero-engine applications, such as gas-turbine discs or blades, due to their high strength and creep resistance. However, oxygen diffusion into the material at elevated temperatures can lead to in a complex failure process known as environmentally-assisted cracking (EAC). With aircraft engine manufacturers driven to increase operating temperatures in excess of 700 oC due to fuel efficiency demands and the need to reduce emissions, EAC in these alloys is becoming increasingly prevalent and is now the major limitation to their use in aero-engine applications. EAC involves many competing mechanical and chemical processes, and a better understanding of these processes is essential to predicting the life of currently used alloys as well as the development of new EAC-resistant materials.The aim of this PhD project will be to investigate how changes in composition and microstructure affect the susceptibility of Ni-based superalloys to EAC. EAC susceptibility is strongly influenced by the rate of uptake of elemental oxygen, the affinity of the material to grow oxides and relaxation mechanisms to accommodate stresses that build up in the material. The student will develop computational models for these highly interrelated processes, and will apply these models to investigate EAC behaviour in newly developed alloys and how they compare with more standard alloys and microstructures currently used.Candidates for this position should have a degree in Materials Science, Physics or related discipline with strong computational skills. Experience is materials modelling is helpful but not essential, however candidates are should be enthusiastic about using mathematics and computers to model materials behaviour. This PhD position will be sponsored by Rolls-Royce. There will be opportunities to spend time at Rolls-Royce and contribute to neutron and synchrotron diffraction experiments led by other university partners. As well as developing excellent computational modelling skills, the PhD student will acquire expertise in advanced Ni-based superalloys and how they are used in aero-engines.