We are a group of researchers specialising in materials science and engineering, primarily of metallic alloys and ceramic / metallic composites.
We are fascinated by materials used in difficult and interesting environments and development of exciting new microstructural characterising techniques.
Our work is primarily experimental, using novel techniques such as high angular resolution electron backscatter diffraction (HR-EBSD) and high spatial resolution digital image correlation (HR-DIC) to track strain and stress at the local scale. We use these to understand microstructural mechanisms and inform models to predict component performance. We also have a number of computational group members, using dislocation dynamics and crystal plasticity methods to understanding materials deformation. Finally, we develop new image processing algorithms to improve our characterisation tools.
We are based within the Engineering Alloys Theme in the Department of Materials, at Imperial College London. The Department hosts a large range of sophisticated experimental kit that we use regularly. We also develop and maintain a number of software analysis tools that aid our experimental understanding of real alloy performance.
Why Micromechanical Characterisation?
Micromechanics is the understanding of mechanics in heterogeneous structures, for us this is within context of microstructure. This is fundamental for creative innovation and design of new materials, as well as management of existing alloys in complex environments. Issues within these environments can span a range of time and lengthscales. Therefore the only solution to generate new insight is through fundamental mechanistic understanding of the influence of microstructure on the performance of these alloys.
In our group we gain this insight typically with a range of experiments, complemented with high fidelity models and simulations, to get to the heart of understanding failure and damage mechanisms in many extreme loading conditions.
This approach enables clear understanding of the behaviour of microstructural components within real materials. With this in hand, we can open up informative and useful discussions with our range of industrial and scientific partners on how to best manufacture or operate components in 'high-risk high-value' applications ranging from jet engines for aerospace, nuclear fuel cladding, and pipe and drill components for oil & gas.
EBSD characterisation of large scale mechanically deformed samples, where we are interested in the heterogeneous nature of slip, twinning and damage to enhance life prediction of engineering components.
Twinning in Zr - from Vivian Tong's work
Twins are highlighted as red lenticular objects using EBSD analysis. The location and frequency of the formation of these twins is controlled by microstructure and mechanical behaviour.
Micro-mechanical testing using in-situ deformation in the SEM. The activation of individual slip systems can be targeted using careful experimental design. Here we are exploring the load relaxation of a fixed displacement load-hold in order to understand dwell fatigue.
Micro-pillar compression of Ti624X - from Terry Jun's work
The deformation of small micropillars (1-5 microns wide) combined with in-situ testing is enable us to probe the local strain rate sensitivity of engineering alloys used in industrial components.