Adventure in Alloy Design

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• Dr Katerina Christofidou from the University of Cambridge Rolls-Royce UTC
• Tuesday 08 January 2019, 14:00-15:00
• Metallurgy and Materials, 2C30.

If you have a question about this talk, please contact Andrew Morris.

As jet engines are continuously evolving to provide improved efficiencies combined with reduced environmental and acoustic emissions, new high temperature superalloy compositions tailored to these new service conditions are required. However, alloy design is a complicated task necessitating an in depth understanding of component requirements, physical metallurgy, the effects of chemistry on a multitude of properties as well as the impact of manufacturing and processing on the underlying material microstructures. In this seminar, two examples at different stages of the alloy development process will be presented; the design of a polycrystalline Ni-based superalloy for turbine disc applications, and the development and understanding of high γ′ fraction superalloys manufactured through laser powder bed fusion methods. In the first instance, experimental results of the microstructural stability and alloy properties will be discussed, in particular as relating to the effect of Nb additions in Ni-based superalloys comprising elevated concentrations of Co. In addition, the use of synchrotron and neutron diffraction methods in obtaining valuable insights for alloy design will be presented with regards to obtaining the γ/γ′ lattice misfits at elevated temperatures as well as in understanding how the load partitioning to the two different phases may be affected as a function of temperature and alloy chemistry. Furthermore, the additive manufacturing example will be used to illustrate the challenges faced at the early stages of alloy development and the importance of a thorough understanding of the material through different stages of post-processing. Experimental results, using SEM -EDX, EBSD , XRD, STEM and RUS , showing the microstructural evolution of alloy CM247LC and a no-carbon variant will be presented and the implications towards future alloy development will be discussed.

This talk is part of the School of Metallurgy and Materials Colloquia series.

This talk is included in these lists:

• Metallurgy and Materials, 2C30
• School of Metallurgy and Materials Colloquia

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