Deformation and stress corrosion cracking in Ni alloys

Alloys are selected for their excellent corrosion resistance and good mechanical properties at elevated temperatures in these difficult environments. Yet work must be done to understand SCC as factors such as microstructure, mechanical properties, and residual stresses impact performance. We will study methods of measuring localised residual stresses and microstructural evolution during their fabrication and use.

Metals are widely used for load bearing applications in complex environments, such as within a nuclear reactor complex. To extend life of the reactor and extend nuclear power capabilities in sustainable energy generation, we must understand their performance over long times in these harsh environments. Complex shape forming and machining are used to match and link them to other components. In these processes, plastic strain and residual elastic stresses are introduced which can impact on their performance over time. One mode of failure is stress corrosion cracking. In order to predict the incubation period for crack initiation and growth, it is necessary to measure the degree of plastic strain in materials and assess other microstructural factors.

Alloys are selected for their excellent corrosion resistance and good mechanical properties at elevated temperatures in these difficult environments. Yet work must be done to understand SCC as factors such as microstructure, mechanical properties, and residual stresses impact performance. We will study methods of measuring localised residual stresses and microstructural evolution during their fabrication and use. This will involve experimental tools such as digital image correlation, mechanical testing, X-ray diffraction and electron backscatter diffraction, as well as use of modelling tools such as the finite element method. The work will help develop an optimised post-weld heat treatment method for the Alloy 600 to Alloy 600 welds, among others, quantifying the influence of the post-weld heat treatments on the residual stress, and as a result, the SCC susceptibility of the welds.

Applicants should have or expect to obtain a good first or upper second class degree (or equivalent) in Materials Science, Physics, Chemistry or Engineering. This project is well suited to a self-motivated student, with a keen interest in mechanics and characterisation techniques. You should also have excellent communication skills including proven ability to write in English.

The project is part-funded by Rolls-Royce Nuclear UTC. For those meeting the criterion of having been ordinarily resident in the UK for three years the studentship will cover tuition fees plus the standard maintenance stipend of £15,863 per annum.