Serrated Yielding in Nickel-based Superalloys

Falls under general theme: Materials engineering - metals and alloys

Nickel-base superalloys are employed in critical components of aeroengines due to their excellent high-temperature strength and toughness. However, mechanical instabilities, such as the Portevin-Le Chatelier effect (serrated yielding) can be responsible for premature failures during engine overspeeding. This project is aimed at understanding and predicting mechanical instabilities in advanced Nickel-based superalloys using microstructural characterisation and physics-based modelling. The mechanisms of serrated yielding will be investigated at a micron- and nano-scale using electron microscopy and atomic-scale characterisation to search to study possible elemental segregation. Deformation models will be defined and validated to quantify the nature of serrations (in terms of serration amplitude and strain to first serration) at different deformation conditions and for different initial microstructures.