Cold dwell fatigue can occur under cyclic loading where the maximum tensile load is maintained for a given duration. The phenomenon is called “cold” dwell fatigue because it is prevalent at room temperature but fades out above 200°C. It has been discovered that this loading regime can lead to a large knock-down in fatigue life in certain titanium alloys, when there is strong crystallographic texture heterogeneity in the material. Cold dwell fatigue was found to be the cause of several relatively recent failures of aero engines, which experienced Ti-64 front fan-hub ruptures https://www.youtube.com/watch?v=KEli6jXRlzI) and is therefore a high priority for aircraft manufactures to better understand the risks this phenomenon might pose to other airframe components, which can have different microstructures and loading regimes.
The aim of this project will be to use advanced materials testing and characterization techniques and modelling to understand the sensitivity of Ti64 materials with heterogeneous textures to damage accumulation around stress concentrations and during crack propagation, under dwell fatigue loading conditions.
This will involve running high fidelity in-situ cyclic loading tests, while employing a digital image correlation technique to measure the plasticity that occurs locally within the microstructure, using model materials that have been sourced with different types of texture heterogeneity. The results of such experiments will be compared to crystal plasticity simulations, using modelling tools being developed in the LightForm research group (https://lightform.org.uk).
Academic background of candidates
Applicants are expected to hold, or be about to obtain, a BSc, BEng, MSc, or MEng in Materials Engineering, Materials Science of Metallurgy.
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If you have any questions about the application process, please contact the PGR Admissions Team ([Email Address Removed]).