Ni superalloys utilised in gas turbine hot sections are mature, and their temperature capability is the limitation to improving engine efficiency and reducing CO2 emissions. The Co superalloys demonstrate higher temperature capabilities and are a potential replacement. Successful alloy development will boost the EU economy by increasing the competitiveness of Rolls-Royce (UK’s largest exporter), and invigorate multi-disciplinary research across the ERA. Other gas-turbine technologies will require research and development due to higher operating temperatures, such as ceramic coatings and mechanical design of turbomachinery.
Superalloys are strengthened by fine coherent ordered γ′ particles that hinder dislocation motion through the γ matrix. The γ/γ′ interface has an associated interface width, and the importance of this width in governing microstructural evolution (coarsening) and associated loss in creep strength is debated. It has recently been shown that the interface width can be controlled with alloying additions. In this proposal, interface widths will be systematically altered across a range of Co-Ni-Al-W-Cr superalloys, measured by atom-probe tomography, and coarsening experiments performed to determine if this width is the rate-controlling mechanism during coarsening. Interpretation will be aided by development of a coarsening model. Coarsening will be related to mechanical properties by performing creep tests on samples with different microstructures, and an extensive TEM study is proposed.
The supervisors, Prof. Seidman, Prof. Voorhees, and Dr. Stone, are world leaders in their respective fields at world leading Universities, Northwestern University and Cambridge University. The application discusses the development of the researcher to ensure his future success on his return to the ERA and a strong outreach proposal that will publicise the Marie Curie program to the general public and develop scientific interest for pre-university students.
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