Performance Characterisation of Lean Duplex Stainless Steel Microstructure for Radwaste Storage and Product Store Application [Sponsor: Sellafield Ltd.; Fully funded]
This PhD is part of the EPSRC Centre for Doctoral Training in Materials for Demanding Environments [M4DE CDT]; it is sponsored by Sellafield Ltd. and will commence September 2018.
Lean duplex stainless steels combine excellent strength with good corrosion resistance, which is achieved by increasing the Mn content on the expense of lowering the Ni content of these alloys, compared to standard duplex grades. Changes in metallurgy ultimately affect the corrosion and stress corrosion cracking resistance, and it is therefore important to understand microstructure behaviour during exposure to demanding environments. Lean duplex stainless steels are now proposed for structural application in product stores and radwaste storage container, with information about microstructure performance in chloride-containing atmospheric environment simply lacking. This makes the prediction of lifetime difficult, and the project therefore aims to address this knowledge gap by elucidating the microstructure corrosion response of different lean duplex microstructures (parent, welded) during exposure to atmospheric environments. Results obtained in this project will provide information for safety case.
Key aim of the project is to better understand mechanisms associated with the corrosion performance of welded grade 2101 duplex stainless steel microstructure in chloride containing atmospheric environments, relevant to radwaste storage in sea-atmosphere. A range of different weld microstructure will be simulated and assessed with state-of-the-art characterisation techniques, including Electron backscatter diffraction (EBSD), Digital Image Analysis (IA) and Correlation (DIC), Scanning Kelvin Probe Force Microscopy (SKPFM), and Scanning Electro-chemical Microscopy (SECM), with the aim to correlate microstructure characteristics to local corrosion performance. Corrosion rates of individual microstructure phases will be obtained, in-situ, as a function of environmental exposure parameters, with the corrosion product development characterised by surface analytical techniques. Corrosion mitigation strategies on basis of environmental control and cathodic protection under atmospheric exposure conditions will also be explored..
About industrial sponsor
Sellafield Ltd. is responsible for safely delivering decommissioning, reprocessing and nuclear waste management activities on behalf of the Nuclear Decommissioning Authority (NDA). As part of this mission Sellafield Ltd. stores a range of waste and product materials pending decisions on their future management. This work is part of a wider programme of on-site and university based research to ensure safe management and storage of products.
This project is funded by EPSRC, the University of Manchester and our Industry partners. Funding is available to UK candidates. EU candidates are also eligible for certain projects. The successful candidates will have their fees paid in full and will receive an enhanced maintenance stipend.