Understanding high strain rate deformation in hexagonal close-packed alloys
File(s)
Author(s)
Fang, Ning
Type
Thesis
Abstract
This thesis focuses on gaining insight into the high strain rate deformation mechanisms of Zircaloy-4 using micropillar testing. Single crystal micropillars were subjected to displacement-controlled compression testing at varying strain rates, with slip behaviour analysed using slip trace and the distribution of strain. This enables systematic exploration of the slip strength and strain rate sensitivity of basal, prismatic and pyramidal slip systems in single slip system deformation. A model to predict the strain rate sensitivity of different slip systems to verify the experimental results was introduced, which was further developed to predict the strain rate sensitivity of textured polycrystalline HCP materials. The micropillar-based experimental results were refined using digital image correlation and crystal plasticity finite element modelling to calibrate "digital twin" experiments, to understand the mechanisms of different deformation and hardening behaviour at varying strain rates. Overall, this thesis aids the understanding and prediction of the mechanical properties of Zircaloy-4, and similar materials, under extreme service conditions better.
Version
Open Access
Date Issued
2023-05-31
Date Awarded
01/09/2023
License URL
Advisor
Britton, Ben
Giuliani, Finn
Publisher Department
Materials
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)