Imaging damage and failure mechanisms in aerospace alloys using neutrons and high energy X-rays

The aim of this project is to apply complementary neutron & X-ray techniques, supported with advanced analytical electron microscopy, to image the microstructure evolution in real time at high temperatures (500ºC and above) and during monotonic and fatigue loading, simulating service conditions inside aeroengines. This novel approach will be applied to Ni-based superalloys with different types of processed microstructures (e.g.’ and ’’ hardening alloys) and also to advanced (ultra-)high strength steels relevant to high-temperature aerospace applications. The performance of aeroengines increases with the temperature of the combustion gases and the efficiency of the transition of the combustion energy into thrust. The high-temperature performance of those structural materials depends on the presence in their microstructure of nano-sized phases and interfaces that act as effective barriers to dislocation motion. Unfortunately the optimised initial microstructures change during service at elevated temperatures, therefore impacting on the aeroengine performance and integrity. The student will use (i) wide angle scattering to monitor phase and texture evolution, stress distribution/load partitioning, (ii) small angle scattering to assess the evolution of nano-scale second phase particles (1-100nm), and (iii) imaging of standard/pre-notched samples to follow crack/microdefect evolution and the local strain fields. Neutrons will allow us to look into larger volumes of material (potentially aeroengine components) and X-rays to achieve enhanced spatial resolution, e.g. close to a crack tip, in smaller samples. Electron microscopy would support this work by looking (ex situ) into precipitate chemistry, interfaces and dislocation structures. This work would allow to validate and improve existing damage models and lifetime predictions in the aerospace industry, ultimately leading to novel and affordable components for commercial passenger aircrafts with enhanced performance-to-weight ratio, and is only possible now with the use of the latest (intense) neutron and hard X-ray sources. The student will have the opportunity to make use of the state-of-the-art electron microscopy suite at the School of Materials, and also to perform complementary neutron & synchrotron experiments at (inter-)national large-scale experimental facilities. This project is embedded within the recently established collaboration between the University of Manchester and the Beijing Institute for Aeronautical Materials (BIAM), and is fully funded via the BIAM-University of Manchester Technology Centre that focuses on the development, processing, testing and characterisation of advanced materials for aeroengine applications.