A funded 3-year UK PhD studentship is available in the research group of Dr Mary Taylor [1] and Dr David Collins [2] at the School of Metallurgy and Materials at the University of Birmingham, with a stipend of up to £21,000 per year. This includes a top-up contribution from Rolls-Royce.
An innovate recent finding at the University of Birmingham was that the heating stage of a heat treatment plays a significant role in the formation of the dominant oxide developed on the surface of a nickel-base superalloy. It was discovered that by selecting the appropriate heating rates, oxides can form with beneficial protection characteristics. Three oxidation domains were identified for the current turbine disc alloy, RR1000, which are approximated as: ≥40oC min-1 leading to Cr2O3 formation, 5oC min-1 leading to a protective NiCr2O4 formation, and ≤5oC min-1 resulting in non-protective oxidation. It is hypothesized that it is the quantity of the precursor oxide that dictates the subsequent oxidation reactions [3]. The scientifically exciting find has motivated us to broaden our study into different alloy systems, which forms the basis for this PhD.
This PhD project focuses on revealing the oxidation behaviour of a developmental Rolls-Royce alloy that will be used in the next generation of gas turbines. New understanding will build on the expertise previously gained on the oxidation behaviour of superalloys, and more recently, the role of heating rates. This project will form part of a broader study which aims to reveal the sensitivity of superalloys to heat treatment conditions, both during manufacture and in-service. An important aspect of this project is the role of minor alloying additions on the resultant oxidation behaviour, particularly the influence to phases formed and the interaction with the microstructure of the base alloy. The effect of a wide range of surface treatments, known to influence oxidation, will be also be examined. The interaction between localised deformation near the surface of the alloy, and the growing oxide kinetics, for example, is not well understood. Linking this to microstructure would represent a step-change in our understanding of our ability to control surface protection. The overall aim of the project will be to produce algorithms that will predict various aspects of the oxidation behaviour that will be incorporated into Rolls-Royce lifing models. If successful, this will be used to propose heat treatments for the alloy to generate the precursor oxides under highly controlled conditions during the production stages.
This project will suit a candidate with a keen interest in using and developing high resolution characterisation techniques. This will include, but will not be limited to, TEM, FIB, EBSD and SEM. The group has also recently been allocated beam time at the Diamond Light Source to perform a high resolution synchrotron diffraction experiment to study the structures of the oxides formed in these alloys; this exciting opportunity will be incorporated into this PhD project. There will be scope for the successful candidate to tailor the project to suit their own interests and strengths.
The successful applicant must hold a first degree (minimum upper second class) in Materials Science, Physics, Mechanical Engineering or related discipline. Experience in electron microscopy and/or diffraction techniques will be advantageous. Applications should be made via the University of Birmingham online application system [4], including a full CV, a covering letter that describes your experience and suitability for the PhD, and the names of two people who can provide a letter of reference.
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