Experimental Micromechanical Characterisation Research Group

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Welcome to the home pages of the Experimental Micromechanical Characterisation Research Group, including Dr Ben Britton and team.

We are a group of researchers specialising in materials science and engineering, primarily of metallic alloys and ceramic / metallic composites.

Our core focus is on understanding the properties and performance of materials in difficult and interesting environments, through development and use of tools that characterise the performance of microstructural components within materials.

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 Group 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.

If you are interested in joining the team - why not check out the available opportunities?

News:

08/05/2017 - The Engineering Alloys Theme (our parent research grouping at Imperial) won an Imperial College President's Award for best Research Team. Ben also won an President's award as an Outstanding Early Career Researcher.

04/05/2017 - New paper on studying fine scale microstructure in Ti alloys - studied with transmission Kikuchi diffraction (TKD)

Tong, V., Joseph, S., Ackerman, A., Dye, D. and Britton, T.B. "Using transmission Kikuchi diffraction to characterise α variants in an α+β titanium alloy"

http://onlinelibrary.wiley.com/doi/10.1111/jmi.12569/full

03/05/2017 - Congratulations to Vivian on graduating today! Her PhD focused on studying zirconium for nuclear applications. Vivian also won a prize for the best PhD in Materials Characterisation in the Department - very well done!

29/03/2017 - Alex talks about his journey into a PhD and shows off some of his neat card tricks - https://www.youtube.com/watch?v=mi6GHZjqU0k

26/03/2017 - Three papers from our work are now available online:

We perform micromechanical testing (in the computer) to explore the role of the beta phase in titanium alloys. Lovely work from Patrick Ashton who visited our labs from The University of Galloway:

Ashton, P.J., Jun, T.S., Zhang, Z., Britton, T.B., Harte, A.M., Leen, S.B., and Dunne, F.P.E. "The effect of the beta phase on the micromechanical response of dual-phase titanium alloys" International Journal of Fatigue (2017)

http://dx.doi.org/10.1016/j.ijfatigue.2017.03.020

Vivian has formed some VERY BIG GRAINS in zirconium and shed some light on their formation:

Tong, V. and Britton, T.B. "Formation of very large ‘blocky alpha’ grains in Zircaloy-4" Acta Materialia (2017)

https://www.sciencedirect.com/science/article/pii/S1359645417301817

Finally, Jun Fionn and Ben have written a review of their work in the "Nickel Campaign" - a three year programme of work to understand fatigue crack initiation in Ni alloys

Jiang, J., Dunne, F.P.E., and Britton, T.B. "Towards predictive understanding of fatigue crack nucleation in Ni-based superalloys" JOM (2017)

http://dx.doi.org/10.1007/s11837-017-2307-9

12/01/2016 - Pre-print of collaborative HexMat work on transmission kikuchi diffraction (TKD) of dual phase titanium alloys now on ArXiv (it is also under review with a Journal)

Vivian Tong, Sudha Joseph, Abigail K. Ackerman, David Dye, T. Ben Britton Using transmission Kikuchi diffraction to characterise α variants in an α + β titanium alloy

http://arxiv.org/abs/1701.03014

28/10/2016 - New paper on twins in HCP alloys. Blog write up here.

Guo, Y., Abdolvand, H., Britton, T.B., and Wilkinson, A.J. Growth of {

} twins in titanium: A combined experimental and modelling investigation of the local state of deformation Acta Materialia (2016)

http://dx.doi.org/10.1016/j.actamat.2016.12.066

20/10/2016 - New paper on deformation in Ni-based superalloys, an excellent joining of experiment and simulation. Blog write up here.

Guan, Y., Chen, B., Zou, J., Britton, B., Jiang, J. and Dunne, F.P.E.

Crystal Plasticity Modelling and HR-DIC measurements of Slip Activation and Strain Localisation in Single and Oligo-crystal Ni Alloys under Fatigue International Journal of Plasticity (accepted)

http://dx.doi.org/10.1016/j.ijplas.2016.10.001

03/10/2016 - Welcome to Alex, who joins the group as a PhD candidate. Alex will be developing new HR-EBSD analysis approaches.

29/09/2016 - Vivian successfully defended her thesis today! Subject to a few minor corrections, she'll soon be Dr Tong - well done! Many thanks to Prof John Wheeler (Liverpool) and Dr Luc Vanderperre (Imperial) for examining her.

23/09/2016 - Ben attended the Recent Appointees in Materials Science conference - story here.

For older news - view the archive

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.

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