Correlative statistical microstructural characterisation of precipitates in ni-based alloys for nuclear power applications
File(s)
Author(s)
Bilsland, Chris
Type
Thesis
Abstract
Within in the nuclear industry stress corrosion cracking (SCC) is a significant issue that limits the lifetime of components in contact with coolant water. SCC is a threat when there is a combination of a susceptible microstructure, environment, and stress. Therefore, development of new material processing methods for alloys may provide an opportunity to address SCC risk through engineering of tailored microstructures. In the literature the factors that result in SCC are often investigated independently, considering the precipitate distribution and grain boundary misorientation character with techniques that target these individually. In this thesis a method will be developed that combines EBSD and EDS data in order to target both distributions simultaneously. This will be applied to Inconel 625 that has been processed via hot isostatic pressing and wrought processing in order to understand the impact that the processing method has had on the microstructural factors of SCC. This was supported by statistical analysis of the precipitate distributions to reveal trends in chemistry by location within the
microstructure.
With the development of this data processing approach, it allows for the analysis of large samples sizes and importantly number of precipitates. This has enabled the determination of minimum sample sizes to demonstrate the statistical significance of the chemical variation in the precipitates by location and also the impact the processing method has on these distributions. Higher spatial resolution techniques such as transmission electron microscopy can be further employed to support the analysis of chemistry of the precipitates identified.
microstructure.
With the development of this data processing approach, it allows for the analysis of large samples sizes and importantly number of precipitates. This has enabled the determination of minimum sample sizes to demonstrate the statistical significance of the chemical variation in the precipitates by location and also the impact the processing method has on these distributions. Higher spatial resolution techniques such as transmission electron microscopy can be further employed to support the analysis of chemistry of the precipitates identified.
Version
Open Access
Date Issued
2022-06-13
Date Awarded
01/03/2023
License URL
Advisor
Britton, Ben
Pedrazzini, Stella
Sponsor
Engineering and Physical Sciences Research Council
Rolls-Royce (Firm)
Publisher Department
Materials
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)